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Water, Water, Everywhere!
11 Posts
February 3, 2011 – 7:13 pm

Welcome to the fun with liquids page! The information here is mostly based on my own personal experience. Working with plumbing is pretty straightforward and usually isn’t terribly dangerous, unless you gouge yourself with a screwdriver or drop a wrench on your foot. However, improperly installed or poorly repaired plumbing can lead to your RV filling with water (or other far more disgusting substances!) so it’s important to do the job right the first time. Some of the suggested RV modifications require you to be at least a little handy… Don’t undertake any project beyond your capabilities.

[size=14pt]Introduction [/size]
One of the best things about an RV is it’s ability to provide all the comforts of home even when you are miles away from civilization. Key to our comfort are simple things like running water and indoor toilet facilities. Any tent camper can tell you how much fun it is to make a 1/4 mile trek to the outhouse at 3 am in a pouring rain, or detail the joys of washing dishes at a spigot. Lucky for us, our modern RVs are equipped with complete miniaturized equivalents of the household plumbing that we all take for granted. Even small RVs have partial or complete self-containment capabilities and the basic design of the plumbing systems are pretty much the same, from a pop up camper all the way up to a big class A motorhome. Let’s take a look at a simple block diagram:
[size=14pt]Block Diagram[/size] Enlarger

See… there’s not really all that much to it after all! A couple of notes: there is a one way valve built into the city water inlet and the water pump has a one way valve built into it.. the valves are shown here separately for clarity. Some rigs have separate sewer connections for the black and gray tanks and a few rigs even have 2 different gray water tanks, but the basic system is still the same… Occasionally, a RV manufacturer will short cut good design principals and plumb the bathroom sink into the black water tank, just because it’s easier. Luckily, few rigs are plumbed in this incorrect manner… More on that later.
[size=14pt]Getting water into your RV [/size]
  Don’t open a roof vent in the rain!  There are easier ways! The easiest is to simply connect a garden hose between the nearest potable water faucet and the city water inlet on the side of your rig. This provides you with water at pressure to all the fixtures in your rig. There are a few important points to note, however!
1. First of all, you will like the taste and smell of your water a lot more if you use a hose designed for drinking water, rather than just any green garden hose.
2. It’s a good idea to have several lengths of hose, as you never know how far away that faucet will be. I have a 10 foot, a 20 foot and a 50 foot fresh water hose and use whichever one or combination of several that reach the faucet the best.
3. NEVER NEVER NEVER use your fresh water hose for any other purpose! Don’t use it to wash the car, or (God forbid!) to flush out your holding tanks! That hose needs to be treated carefully and kept as sanitary as possible. After all, you’re DRINKING this water, right?
4. RV plumbing was designed to operate at pressures of 40 to 60 psi and most can tolerate pressures up to about 100 psi. Unfortunately, unregulated city water can have pressures as high as 150 psi or more. The best bet here is to always install a pressure regulator on the line coming to your city water connection. There are inexpensive pressure regulators that simply screw onto one end of your fresh water hose and they are cheap and effective insurance.

Taking your water along for the ride.  If you won’t be having the convenience of a fresh water spigot at your destination, then you’ll have to take water with you using your rig’s fresh water holding tank. Filling the tank is as easy as hooking your fresh water hose to a nearby faucet and running water into the water tank fill opening on your rig. These fresh water fills come in many shapes and sizes…. here’s a typical example: Enlarger

Make sure that the tank drain valve, if there is one, is closed before starting to fill the tank. If your tank has a vent valve, it’s best to open it to allow the tank to fill faster. If your tank glugs, chuffs and spits water back at you when filling, then it’s likely that it has no vent or the vent is plugged or shut off somewhere. Simply slow down and let the tank fill at it’s own rate. You can make the task easier by using a little fill adapter like this… it fits on the end of the hose and then slips down into the filler. A handy little device to have. Enlarger

Another really handy device to have is a water stealer. These little homemade items allow you to hook up a hose to a faucet that has no hose threads. These little devices will allow you to fill your fresh water tank from just about any spigot or sink tap that you will find anywhere. They are cheap and easy to make and will save you a lot of headaches somewhere down the road! To use, just force the end of the appropriately sized stealer over the non-threaded spigot and secure with the worm gear clamp. Attach your hose and you’re in business. Note: these are for temporary hookups for filling a water tank and really aren’t designed to have pressure on them for long periods of time. Probably not a good idea to use as a permanent hookup! Enlarger

To make a set of your own water stealers, just hit the local hardware store and buy short sections of 3/8", 1/2" and 5/8" I.D. clear vinyl thick walled tubing and the male garden hose ends to match the hose sizes. A little work with pliers and screwdriver and you’ll have your own set of stealers!

Once the tank is full, or as full as you want it, shut off the water and stow your hose and stuff. Don’t forget to secure the fill cap and close any vents if you have them before heading down the road.

[size=14pt]Getting water to the fixtures[/size]
– If you are hooked up to a fresh water faucet, then there ain’t much to it! Hook up the hose to your city water inlet, turn on the faucet and open a faucet inside the rig to allow any air to escape. It’s a good idea to purge all the sink and tub fixtures and to make sure that the water heater is filled.

– If you are in a boondock or dry camping situation, you must rely on the 12V water pump in your rig to supply water under pressure to the fixtures. To get started, open a cold water faucet in the rig and turn on the pump. Having a faucet open will help the pump prime quickly. When the water is flowing nicely, close the faucet. Briefly open each faucet throughout the rig to purge out any air. Once this is done, the pump should stop running after you close the last faucet and shouldn’t run again until you open a faucet somewhere. The pump is designed to pump the system up to about 40-50 psi and then a pressure sensing switch mounted on the pump shuts the pump off until the pressure drops. You are all set… just remember that your supply of fresh water is limited and conserve it! When the tank runs out, you will hear the pump speed up and the flow of water from the fixtures will slow or stop. It’s best to turn the pump off at this point until you refill the fresh water tank. These pumps can run dry for an extended time without damage, but it’s a waste of power to just let it continue to run, so be sure to turn the pump off when the tank runs dry.

[size=14pt]We’re in hot water now![/size]
  –  Unlike the water heater in your house which requires little or no user intervention, operating the typical RV water heater requires you to pay attention to a couple of things…

1. First and most important, before lighting the water heater gas pilot or turning on any electric heating function, make SURE that the water heater tank is filled with water!!! Check to be sure that the water heater inlet and outlet lines are not bypassed with a winterization bypass kit and that water flows from the hot faucet in the sink or shower.

2. Once you’re sure, go ahead and turn on the heater. Some heaters utilize an electric heating element in addition to the standard gas burner. Some heaters require a pilot and some are Direct Spark ignition. Check the manual that came with your RV or the data plate on the water heater itself for proper lighting and operating instructions.

3. Most RV water heaters allow some adjustment of the water temperature. Gas models will have a temperature adjustment right on the gas valve. Gas/Electric units will also have a separate thermostat for the electric side, but locations and accessibility will vary. Best to consult the manual unless you like to play detective… Be careful not to set the temperature too high… it’s easy to get severely scalded by water heated beyond 140 degrees.

4. It is not uncommon to see some weepage from the pressure relief valve on the outside of the water heater when initially heating a tank of cold water. This is caused by the expansion of the heated water and indicates very high pressure within the water system. You can open a faucet briefly to relieve the pressure, but the best permanent fix for this problem (in my opinion) is to add a small expansion tank to your water system. The expansion tank will absorb the pressure fluctuations and smooth the water flow in your rig. See the Enhancements section for more info.

5. If you have a water heater that utilizes a pilot light, you may be amazed to find that the pilot will heat your water nicely all by itself. Just light the pilot and leave the gas valve in the ‘pilot’ position when you park and overnight the water will heat up and be ready for your shower in the morning. This doesn’t work well in high usage situations, but can be a real propane saver for the frugal RVer!

[size=14pt]Where does it go from here[/size]
In a non-mobile house, once the water disappears down the drain, we can forget about it. Not so in a RV…. Every drop winds up in the holding tanks and then we must at some point deal with it again. Let’s look at that block diagram again…. the waste waters from the sinks and shower are transported to the Gray Water tank through a series of pipes. Each drain has a standard plumbing trap that keeps the sewer odors from coming back up through the drain. The gray water builds up in the tank until we dump it. Similarly, the toilet dumps directly to the black water tank through a foot or lever operated valve. This valve seals off the tank when the toilet is not being flushed and keeps the odors in the tank where they belong.
In most cases, the black and gray tanks are sized slightly smaller than the fresh water tank… usually somewhere between 20 and 50 gallons each, although truly large rigs may have tanks approaching 100 gallons each. The best source of capacities information for your particular rig is either the owner’s manual or the dealer. It’s handy to know the actual capacities of your plumbing system because water weighs! It’s safe to figure about 8 lb. per Gallon for water and waste liquids and you can see how it can add up in a hurry! A 50 gallon fresh water tank, when filled, is going to add 400 lb. to the weight of your rig. Traveling with full holding tanks can add a lot of weight and easily put your rig over it’s safe operating weight. Be aware of your rig’s dry weight by weighing it fully loaded, but without fresh water or propane onboard and with empty holding tanks. Compare this weight to the unit’s GVWR.
GVWR – (dry weight) = available capacity for water and propane
Propane weighs about 5 lb. per Gallon…. Be careful not to overload your rig and always be aware that water has weight and must be considered as part of your payload!

Many RVers have discovered that when dry camping or boondocking, the gray water tank tends to fill up pretty quick while the black water tank rarely ever fills up. This makes sense, as the only source of fluids for the black tank is the very efficient RV toilet. The gray water tank has to contain the liquids from all the sinks and the shower. Strangely enough, however, most RVs have black and gray tanks that are the same size! Given the above, it seems like a lot of tank capacity is going to waste here and I decided to do something about it. I designed and installed a simple transfer pump that will move gray water from the gray water tank to the black water tank. Details on the transfer pump are included below in the Enhancements section.

Occasionally, a RV manufacturer will ignore good design engineering and plumb the bathroom sink and/or even the shower into the black water tank, just because it’s easier and cheaper. Beware this setup! It makes it possible to overflow your black water tank by running water in a sink or shower that common sense says is connected to the gray water tank. If your black water tank seems to fill up awfully fast, you might just be the lucky owner of one of these mis-plumbed rigs. If you suspect non-standard plumbing in your rig, the best way to check is to be at a full hookup site. Dump both tanks. Close the black tank dump valve and leave the gray tank dump valve open. Run water into all sinks and shower for several minutes and monitor the black water tank level. If water shows up in the black tank, then you have one or more sink drains plumbed to it. This doesn’t mean that you must immediately sell your RV and buy another… it just means that you are now aware of a potentially annoying and destructive "feature" and you should keep a close eye on the level in your black tank. In most correctly plumbed rigs, when you completely fill up the gray water tank, the drain water will begin to back up into the bathtub or shower, which is usually the lowest point in the gray water system. This is pretty harmless…. after all, it’s just soapy water and it’s not going to hurt anything. However, if a sink or shower is plumbed into the black tank and it becomes completely full, then what backs up isn’t going to be soapy water! Plus, it may not back up into such an innocuous place as the tub. Thankfully, this kind of problem seems to be pretty rare, so your rig is most likely correctly plumbed.

Most folks agree that the gray water tank can be dumped anytime, no matter how full or empty, and when you are hooked up to a sewer connection, the gray water dump valve can be left open at all times. This allows the water from your sinks and shower to flow directly out of the rig and into the campground sewer system. Hey, that’s easy! However, it is not a good idea to treat your black tank the same way. Black water contains a lot of … well… call them ‘solids’. RV toilets flush with very little fresh water, so these ‘solids’ are quite concentrated. If you were to leave the black water dump valve open while hooked to a  sewer connection, these solids tend to build up in your tank and then dry into a disgusting form of concrete. Over time, a black tank can become partially or completely blocked, leading to a highly nasty cleaning job or complete tank replacement. To avoid this, always keep the black water tank dump valve shut. Let the black water build up until the tank is at least 1/4 full and then dump it, rinsing with lots of fresh water. Waiting to dump the tank keeps all those ‘solids’ in suspension and the quick rush of fluid out of the tank when it is dumped helps carry most of the solids out. Whenever it’s convenient, try to dump the black tank after traveling… the motion of the rig on the road will mix up the contents nicely and help break down the ‘solids’. When parked for an extended period, I usually dump the black tank every couple of weeks if the weather is cool and more often when it’s hot. (helps keep the odors down!) The day before I plan to dump the black tank, I shut the gray tank dump valve. This allows some gray water to build up in the tank… then, when I dump the black tank, I follow it with the gray tank to flush out the hose and help carry the whole mess down the sewer pipe to wherever it ultimately ends up.

[size=14pt]Don’t put this stuff down your drains![/size]
– Grease or oil. It will congeal in the tanks and pipes and require dynamite to remove!
– Caustic cleaners or solvents. Tanks are ABS plastic and solvents can destroy them!
– Flammable liquids. Duh!!!
– Toxic wastes. More Duh!!!
– Food scraps. Even small scraps can build up in your tanks… consider a drain screen!
– Don’t flush anything down the toilet unless you’ve eaten it first!! No tampax, paper towel, bottle caps, toys, Q-tips, cotton balls, etc, etc, or you’ll be SORRY!
– Don’t use that quilted 3 ply toilet tissue you love…. Sorry! It’s best to use either an inexpensive one or two ply tissue you can get at your local food store or stick to RV toilet paper. Both work about the same, but the RV stuff is about 4X the cost! Whatever you use, it needs to disolve fully in your tank. If in doubt, always do the jar test: take a sheet or 2 of your TP, put it in a jar 1/2 full of water and give it a shake. Safe TP will dissolve readily, bad stuff won’t and shouldn’t be used in your RV!
– Toilet chemicals containing formaldehyde or any other crap that ends in "dehyde". Don’t use this stuff! It plays havoc with sewage treatment plants and septic systems alike. Don’t believe the B.S. about it being biodegradable…. it’s doom and is one of the reasons that so many public dump stations have been closing.
– Pine oil. Favorite ingredient of home-brew tank treatments, it will do long term damage to the seals on the tank gate valves, leading to expensive and disgusting repairs down the road.

This and additional related information can be found at:

11 Posts
February 3, 2011 – 7:25 pm

[size=14pt]Toilet Chemicals[/size]
I’m really gonna step WAAYYY out on that proverbial limb and talk about a very controversial subject. What to put down your toilet to help control ‘Odors’. The reason that this is such a scary topic is that absolutely everyone has a favorite toilet chemical. They are also certain that the inferior substitute you are using is nowhere near as cheap, effective, safe or easy to use as their favorite. OK, I’m joking… a little…. If you ever want to start a lively discussion around a campfire, ask what your neighbors are using for their toilet!
Personally, until recently, I rarely put any kind of chemical in my black water tank. I simply dumped my tanks more often when it was hot to avoid serious odor problems. In the winter, when cold weather reduced the odors anyway, I never bothered with chemicals at all. Most of the commercially available chemicals are bad for the environment, tough on sewer treatment plants, expensive and only marginally effective at best. I figured that it was ‘Money down the drain" and just didn’t use any of it.

Nowadays there are a number of enzyme and bacterial tank treatments on the market. These products are designed to stimulate aerobic bacterial action and break down the waste and kill the odors… kind of like having a miniature sewage treatment plant onboard. They carry an added benefit in being completely biodegradable and highly beneficial to RV park septic tanks and sewer treatment plants as well.

If you decide to stick with old fashioned toilet chemicals, please use them sparingly and avoid using any product with Formaldehyde as the active ingredient. Most home brew toilet treatments should be viewed with a skeptical eye. Don’t even consider using a home-brew remedy that has pine oil or Pine Sol in it. Pine oils will harden the seals on the dump valves and eventually cause leaks.

[size=14pt]Monitor panels[/size]
All RVs come equipped with some sort of monitor system that is supposed to tell you how much ‘whatever’ is in your tanks. These systems haven’t changed significantly in the last 30 years and most still rely on physical conductive probes inside the tanks. Here is a simplified diagram to show you how this is all supposed to work. Enlarger

For the most part, this system works pretty good for the fresh water tank and the gray water tank, but leaves something to be desired for the black tank. Most folks find that after a year or two, the sensors in the black water tank stop working. This is due to the probes getting coated with yuck in the tank and this yuck interferes with the accuracy of the monitor. There are literally dozens of expensive tank cleaning concoctions on the shelves of your local RV store and there are almost as many home-brew cleaning ideas out there… some work better than others, but nothing will fix the problem permanently. My favorite home-brew tip is to put a few gallons of clean water and a small amount of dish soap in your freshly dumped black water tank and then add a large bag of ice cubes. Drive the rig for a few hours, then dump when you arrive at your destination. The idea is that the ice cubes will scrub the insides of the tank and then melt. It’s worth a try if your monitor panel isn’t working right…
When it comes to the standard monitor systems installed in most RVs, they are just likely to be inaccurate in use. You can either put up with it, do a regular cleaning of the tank probes and hope that it helps, or invest in a replacement tank monitoring system. There are a couple of different ones out there on the market and they work without any probes inside the tank. One popular system uses capacitance and simply requires a couple of sensors be placed on the outside of the tank body. My black water tank monitor never worked, even with repeated cleaning, so I just ignored it. When the gray water tank monitor started to act up, I decided it was time for a better answer. I purchased and installed a system called Acu-gage and I have been very pleased with it.. It is amazingly accurate and linear and has worked flawlessly for more than a year.

[size=14pt]Dealing with dumping[/size]
Probably one of the least enjoyable tasks associated with RVing is getting rid of the waste water that accumulates. It’s really not so unpleasant, if you do it right.
First of all, buy good quality hoses and fittings…. the heavy duty sewer hoses cost a little more but will last a lot longer and are more resistant to springing leaks. It’s a good idea to have both a 10 foot and a 20 foot sewer hose. Equip each hose with the correct fitting to attach it to your rig’s dump connection. It is also a good idea to have at least one set of sewer adapters to connect your sewer hose to the sewer fitting in a RV park. I use the red E-Z couplers and really like them, as they simply screw into the sewer hose, needing no additional clamps. They provide a neat leak proof connection to the park’s sewer system and are quite inexpensive.

There are a number of other brands on the market as well… just pick out whichever one you like. The unused pieces can be stored in large Ziploc bags in a compartment. The flanges are removable and the elbows are designed to stay on the hose and fit either into your bumper stowage or in a custom sewer hose storage.
At the dump station or sewer connection, park the rig close enough for your dump hose to reach. Connect the hose to the rig first, then place the other end into the sewer opening in the ground. If it doesn’t want to stay put, you can place a small rock or brick against it to hold it in place. A piece of wood or a leveling block can also be used. We don’t want that end of the hose to jump out when we start to dump, now do we…. As a last resort, you can ask your spouse to hold onto it, but this is probably the least desirable solution, especially if anything goes wrong!
Pull the Black Water tank dump valve first. This way, you will dump the black water through the hose first, then follow it with the gray water to flush out the hose. Once the black water tank is empty, you should rinse out the tank with clean water. This can be done by dragging a garden hose into the bathroom and running water down the toilet, or you can use a special flushing stick through the toilet dump valve. Another possibility is to step on the small pedal to fill the toilet bowel full and then quickly flush the toilet. Do this a few times and it will rinse out the black tank to a small extent… If all this sounds like a hassle, (and it is!) check out the installable tank flushers in the Enhancements section below.
Once the black tank is empty and flushed out, close the black water dump valve. Now, open the gray water dump valve. As the gray water runs through the hose, you can shake it around a bit to help rinse out the inside of the hose, but be careful not to shake too hard and dislodge the hose from either the rig or the dump. Once the gray tank is empty, shut the valve and wait a few moments before disconnecting the hose from the rig. Disconnect the rig side first and lift the hose up so that any residual water drains into the dump fitting. Now’s the time to rinse out the sewer hose if you like, using a water hose. DO NOT use your Fresh water hose to do this!!! Most dump stations have a water faucet nearby and sometimes even a hose, but it’s a good idea to have a short section of hose of your own and only use that hose for rinsing when dumping.
Put all the caps back on. Cap off the dump connection on your rig and replace whatever cover or plug that belongs with the park sewer connection or dump station connection. Shake out your sewer hose and stow it and it’s adapters. Make sure that you rinse away any spilled waste or mess, especially at a public dump station and stow your rinsing hose and close all compartments. OK, you’re ready to go! … Now, that wasn’t so bad, was it? Oh… It’s a great idea to wash your hands at this point…. Some folks like to use disposable plastic gloves… they put them on before starting and then just discard them afterwards. I keep a small bottle of liquid soap right in the same compartment where the hoses and stuff are stowed… makes it real quick and easy!

[size=14pt]Water quality issues / Filters[/size]
Traveling around the country, you will find that the taste and purity of the available water changes as much as the scenery. There are a lot of things that we can do to improve the taste and safety of the water we put into our rig. Let’s talk about the safe water issues first.

Safe water means water that won’t make you sick. Safe water is water that doesn’t have excessive bacteria, cysts, viruses,  chemicals, heavy metals or other health threatening substances dissolved in it. The easiest way to protect yourself from these nasties is to only use water from an approved city water supply or well. This isn’t a guarantee, but it does improve your chances of getting water that won’t kill you. Chlorinated water is safest and usually won’t have infectious bacteria or organic yuck in it, but you are at the mercy of the water supplier when it comes to other contaminants. Thankfully, most of the water you encounter in your travels won’t kill you or even make you sick but you can improve your odds by remembering a few simple tips:
– Only hook your hose up to a potable water source. Watch out for faucets at dump stations and heed warning signs.
– Use only drinking water safe hoses to supply water to your rig.
– Never use your drinking water hose for any other purpose.
– Stow the drinking water hose empty and connect the ends together to keep them clean.
– Don’t drag the end of your drinking water hose on the ground.
– Always let the water run for a bit at the spigot before connecting up.
– Sanitize your fresh water tank at the start of the season and drain it if it will be unused for more than 2 weeks. To sanitize the tank and the fresh water system, follow your RV manufacturers instructions or do the following:
    1. Prepare a chlorine solution using one gallon of water and 1/4 cup of Clorox or Purex household bleach (5% sodium hypochlorite solution).  Pour one gallon of solution into tank for 15 gallons of tank capacity.
    2. Complete filling of tank with fresh water.  Turn on the pump. Open each faucet and let it run until all air has been released from the pipes and entire fresh water system is filled. You should be able to smell chlorine strongly at each faucet.
    3. Allow to stand for three hours.
    4. Drain and flush the tank and system with potable fresh water.
    5. To remove any excessive chlorine taste or odor which might remain, prepare a solution of one quart vinegar to five gallons water and allow this solution to remain in tank overnight or longer.
    6. Drain tank and again flush with potable water.
– If in doubt about the quality of the water going into your fresh water tank, add a small amount of common household bleach to the water in the tank. A teaspoonful of bleach per 20 gallons of water is plenty!
– If you are really worried, buy bottled water and use it for drinking and cooking!

You can really improve the taste and enhance the safety of your drinking water by installing an under-the-counter water filter. Many rigs already have them and they may be plumbed into the cold side of the kitchen faucet or have a separate faucet for filtered water. My rig was originally plumbed with an ADC filter that dispensed through the cold side of the sink faucet. I replumbed it so that it had it’s own little faucet. This filter system is one of the better ones, as it removes cysts and bacteria as well as bad tastes and odors. The cartridges last about a year with normal use and the whole system is available from any RV supply catalog or parts store. Enlarger Enlarger

There are also excellent filters available that attach right to the water hose outside the rig. These filters come in a disposable type and a replaceable cartridge type and are fairly reasonable in price. The only problem is that they don’t seem to last as long as a dedicated under sink filter. Part of the reason is that the under sink filter only filters drinking water… these units on the hose filter ALL the water going into the rig. If the water is really nasty where you are parked, it can be real handy to have both the under counter filter and one of these hose filters so you can do a ‘double whammy’ on the water before you drink it. This double filtration will make even the most icky water semi-palatable.

For the ultimate in filtration, a Reverse Osmosis system can be purchased. Although these systems produce excellent water, they have some drawbacks when used in RVs and may not be for you. They are quite expensive and take up a lot more space than a filter. They require a fair amount of water pressure to work and also create a certain amount of ‘waste’ water. Some systems produce a gallon or two of waste water for every gallon of filtered water! In a home, that’s not a problem, as the waste water goes down the drain. In a RV, where both the supply of water and the holding tank capacities can be limited, this can make the R.O. system unusable. If you always have a water and sewer hookup, then it’s no problem… but if you like to boondock, you should probably steer clear of this type of system. Too bad, as the R.O. systems remove practically everything from the water.

When I’m traveling, every time I stay somewhere that has tasty water, I fill a few gallon water bottles and stash them. Then, when I stop somewhere that has icky water, I just use my gallons of good water for drinking and cooking. It seems to work out pretty well for me…..

Most older RV fresh water systems are plumbed using gray polybutylene tubing. Most connections are made using barbed connectors made of either gray plastic-like materials or brass and either aluminum or copper crimp rings. This plumbing will resemble the picture below. There have been a lot of claims that polybutylene plumbing breaks down and eventually leaks, usually at the connections. I spent some time researching these claims and I’m sad to say that there appears to be a pretty good case against the gray stuff. One thing is certain: they aren’t making it anymore! It has been universally replaced by cross-linked polyethylene tubing in most newer RVs. Identified by it’s white or red color, PEX is assumed to be safe and reliable. The connections are made either with Qest fittings or the familiar crimp rings as seen below. Enlarger

While scientific evidence is scarce, it is believed that oxidants in the public water supplies, such as chlorine, react with the polybutylene piping and acetyl fittings causing them to scale and flake and become brittle. Micro fractures result, and the basic structural integrity of the system is reduced. Thus, the system becomes weak and may fail without warning causing damage to the building structure and personal property. It is believed that other factors may also contribute to the failure of polybutylene systems, such as improper installation, but it is virtually impossible to detect installation problems throughout an entire system. In most cases it takes years for polybutylene systems to fail. While it may leak within a few years of installation, the majority of leaks start to occur in the 10-15 year time frame.

Throughout the 1980’s lawsuits were filed complaining of allegedly defective manufacturing and defective installation causing hundreds of millions of dollars in damages. Although the manufacturers have never admitted that poly is defective, they have agreed to fund the Class Action settlement with an initial and minimum amount of $950 million. Homeowners with houses that were plumbed with polybutylene are eligible to receive payment to replumb their homes…. unfortunately, RVs of all types were specifically excluded from the class action lawsuit settlements. The following is excerpted from the class action settlement documentation:

A "Unit" is any real property or structure situated in the United States with PB Plumbing installed between January 1, 1978 and July 31, 1995. A "Type I Unit" is a single-family residence, and each part of a commercial or other structure occupied by a single tenant or tenant group. A "Type II Unit" means a mobile home (exclusive of recreational vehicles, boats and travel trailers).

Well, now that I’ve ruined your day, where do we go from here? One good point is that the gray stuff seems to be pretty reliable in the low water pressure environment of an RV. The other good point is that, unlike the plumbing found in houses, the plumbing in RVs is a lot more accessible. Repairs on your polybutylene piping should be done by replacing the old gray stuff with the newer PEX tubing. Qest fittings and the old style brass crimp fittings appear to be compatible with both types of tubing.

Here’s an example of some of the many shapes and connectors you might see when looking at your RV plumbing. Don’t be alarmed by all the variety… it all breaks down into a couple of sets of hardware, depending on the inner diameter of the tubing. Any good RV parts place will have a selection of PEX tubing, fittings, the crimp rings and often even a crimping tool that you can borrow or rent. This stuff is easier to work with than you might think!

These are some typical barbed connectors and fittings. To add a fitting such as a tee to an existing run of poly tubing, simply drain the tubing, cut it using a knife, saw or special tubing cutter and clean up the cut ends, removing any plastic fuzz. Then, place a copper or aluminum ring over each end of the cut tubing and then simply push the tubing onto the barbed fitting. Once it’s fully seated, slide the crimp ring up to the end of the cut tubing and apply the crimp tool to create a finished connection.

If all that sounds like too much work, then you are in luck! There are a number of different repair fittings available for the poly tubing that work on the compression principle. One of the brand names is QEST and these fittings are also available at most RV parts shops and through most RV parts catalogs. To use these fittings, simply cut the tubing, assemble the fitting according to the package directions and tighten the compression nuts. These fittings are substantially more expensive than the more simple barb and ring ones, but are very convenient and easy to use. Enlarger

This and additional related information can be found at:

11 Posts
February 3, 2011 – 7:43 pm

Most faucets used in modern RVs are similar to those used in standard housing and many share the same parts. You can find washers and repair parts for most RV faucets and fixtures if you simply take the defective part with you to the local plumbing shop. The low pressure lines used to supply water from your fresh water tank to the water pump are common vinyl tubing, available at most hardware stores. The waste plumbing is standard household black ABS fittings with very few exceptions. Sink drains, traps, connectors and drain pipes are all standard sizes and types. Replacement parts are available at most hardware stores and the piping is usually joined using ABS plastic pipe cement and standard fittings. The only departure from standard plumbing parts are RV specific items like dump gate valves and sewer hose connector fittings and some of the external drain valves and fittings. The bottom line is that RV plumbing is easy to repair and modify. If you have basic plumbing skills, you should have no problems with your RV plumbing. For those of you without basic plumbing skills, the good news is that RV plumbing is pretty reliable and it’s unlikely that you will experience many problems. The most important thing to remember is to protect your RV plumbing from freezing temperatures, and we’ll discuss that in the Winterizing section below.

Being a born tinkerer, I made a number of changes and enhancements to the basic plumbing in my RV. Some of these modifications are presented here and it’s up to you to decide if they might be useful to you. If you install any of these mods, please be careful to do a good quality job and test each new fitting under pressure, watching for any signs of leakage. It’s a good idea to keep an eye on any new fittings for a couple of days until you are sure that they are secure and leak free.
Toilet sprayer
Some rigs come equipped with a sprayer for the toilet from the factory. Mine didn’t, so I added a standard sink sprayer and teed it off of the water supply line to the toilet. While I was down there, I also added a shut off valve to the supply line. This sprayer is useful to rinse down the inside of the bowl after use and will help to break up any… umm… well, when I was in the Navy, we called them skidmarks…  you get the idea.  🙂  The third photo shows an awfully dusty shot of the connections for the sprayer.. looks like I need to clean back there a little more often! Parts needed were a barbed shutoff valve, a barbed tee with the correct size threaded fitting for the sprayer connection, the sprayer, a broom bracket to hold the sprayer head and the necessary crimp rings. Enlarger

Built in regulator
After leaving my external water pressure regulator behind for the second time, I decided to eliminate the problem by installing a Shur Flo regulated city water inlet. This is a great little device and is easy to add to your rig. It regulates the incoming water pressure to a safe 45-50 psi and since it’s attached to the rig, it’s harder to leave behind. An added benefit; this regulator seems to flow more water than the little brass ones that you attach to the water spigot. For those of you who would rather have an external regulator, they also make one set up with hose connectors. If you are unhappy with the low flow rates you are getting through your current regulator, this would be a good replacement for you. Available from most RV parts stores through the Shur Flo catalog.

Tank flushers
This is a  very useful item and will make your life a lot easier. It’s a tank flushing system that installs permanently into the side of your holding tank and provides an external hose connection so that you can easily flush your holding tank. No more dragging a hose inside to flush your black water tank! I installed one in both my gray and black water tank and I absolutely love them! The instructions are very good and the installation is easy enough for even the moderately handy person to do. Basically, you will need to cut a small hole in the side of the holding tank and attach the flusher head using the provided screws and some silicon sealant. Then the simple hose extension is run to a convenient spot under the rig and provides the hookup point for your garden hose. Inexpensive and a real hassle saver! These flushers can be purchased from most RV stores and camping catalogs. Enlarger Enlarger

Water heater bypass
If you are in the habit of winterizing your RV with RV antifreeze, this little addition will save you gallons of the pink stuff! Some RVs have these installed from the factory, but for those of you who don’t have one, several different brands are available. What this does is allow you to completely bypass the water heater so that when you fill your water system with RV safe antifreeze, you don’t have to fill the whole water heater as well. The picture shown is a factory installed setup…. but it gives you an idea of how it works. To bypass the water heater, drain it and then close the valves on the heater inlet and outlet and open the bypass valve. Check your RV catalog…. most units are simple to install and don’t require cutting any existing plumbing and simply screw onto the existing water heater nipples. One note… if you don’t use antifreeze to winterize your rig, then there really isn’t any reason to install a bypass…. Enlarger

Pressure gauge
This is a mighty handy little item! It’s a simple pressure gauge installed inside the rig to monitor water pressure in your fresh water system. It’s very simple to do… just purchase a standard gauge that will read from 0 to 100 psi or more and add a tee anywhere in the freshwater plumbing. I added mine right next to the water heater. If you are in the habit of not using a regulator, this gauge is a real necessity. To protect your RV plumbing, you should never expose it to water pressures in excess of 100 psi and actually, you are much safer limiting the pressure to 45-55 psi. Enlarger

Gray water transfer pump
Here’s one that’s a little more involved… I noticed early on that when dry camping,  my gray water tank filled up in a few days, but my black water tank would hardly be at 1/4 full. This seemed like a waste of tank space to me, so I devised a pump setup to allow me to transfer gray water from my full gray tank to my relatively empty black tank. This is a great way to extend your stay, especially when you have a water hookup, but no sewer connection! If you are interested,  Coming Soon!
Expansion tank
This is a do it yourself version of the commercially available expansion tank setup for your RV. An expansion tank helps smooth the water flow in your RV and also allows for the expansion of  water in your water heater. If your water heater relief valve leaks or your faucets drip when your water heater is operating, then this is one for you! An added benefit is that it reduces pump cycling when operating on internal water. It’s a cheap and easy installation and you can  Coming Soon!

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Possibly the most important thing you can do to ensure the long life of your RV plumbing is to properly winterize your rig. For those of you who live in climates where it never drops below freezing, my congratulations! You can skip this section! Many of us, however, will be storing a rig in freezing temperatures during the winter months. It is critical that you take the proper precautions to protect your plumbing from freezing, or you will be faced with some nasty surprises come springtime.

To prepare your rig for winter storage:
1. Drain all tanks. Flush out the black water and gray water tanks and be sure to get them as empty as possible.
2. Drain water heater.
3. Drain fresh water system using low point drains if provided. Open all faucets and step on the toilet pedal as well. Get as much water out of the system as possible.

Now, you have a choice… you can either protect your fresh water piping by using a non-toxic RV approved antifreeze or you can use air pressure to blow out the remaining water in your water lines. Both methods have advantages and disadvantages. Using RV antifreeze is probably the surest method to absolutely guarantee that no pipes will freeze. Properly used, it will protect your rig well down into sub-zero temperatures. It does require a lot of flushing in the spring to get the taste out and also makes it desirable to install a water heater bypass to reduce the quantity of antifreeze used. Plus, the stuff ain’t cheap.


NEVER use any antifreeze or substance in your fresh water system unless that product is specifically labeled as non-toxic and safe for use in drinking water systems. Use only antifreeze designed specifically for RV water systems!

In order to easily pump the antifreeze throughout your water system, you can install a neat little valve that allows your pump to draw antifreeze directly from the bottle. It’s available from most any RV parts source.

Alternately, you can remove the existing hose from the inlet side of your water pump and attach a short piece of hose to reach into the antifreeze bottle.  Bypass the water heater if you can. If you have an ADC filter under the sink, install the manufacturer’s antifreeze diverter. If you have a cartridge type filter, remove the filter element and replace the cartridge holder. Run the pump and open each fixture, allowing it to flow until you see pure antifreeze. Monitor the level in the antifreeze bottle and make sure it doesn’t run dry. Remember to flush the toilet and operate the toilet sprayer if installed. Don’t forget the shower head. Depending on the size and complexity of your plumbing system, you will probably need 1-3 gallons of antifreeze. If you don’t have a water heater bypass, better add 6 or 10 gallons to that, depending on the size of your water heater! Once you have done each and every fixture in the rig, you should have full protection against freezing pipes in your freshwater system.

Instead of using antifreeze, you can use air pressure from a compressor to blow the water out of your fresh water lines. This method is cheaper than the antifreeze method and you won’t have to flush the antifreeze taste out of your water system come spring. On the down side, however, it is extremely hard to get every last bit of water out of the lines and if sufficient water collects in a low point or valve, then it may be damaged by freezing. Plus, there are portions of the water system that blowing the lines won’t clear and you must drain them manually. Still, many people prefer to use air to clear the lines, rather than deal with the antifreeze. To start with, you will need a little plug that will fit into your city water inlet and provide a fitting to connect the air compressor to. It looks like this:

Hook up your air source and set it for a max. of 60 psi. Once pressure is applied, go through the rig, starting with fixtures closest to the inlet and open them briefly, allowing the air pressure to blow the water out. Remember to flush the toilet and operate the toilet sprayer if installed. Don’t forget the shower head. Once you have done each and every fixture in the rig, you should have most of the water out of your freshwater system. Remove the air source. Now, it will be necessary to remove the outlet line and inlet line from your fresh water pump and drain them manually, as the check valve in the pump prevents the air from clearing these lines. Remove any cartridge from any under sink filter and make sure the fixture is drained. Your freshwater system should now be in good shape for the winter storage months.

Now, you need to pay attention to the other plumbing systems in the rig….
      1. Pour a small amount of RV antifreeze down each drain to protect the trap. Additional antifreeze can be poured down a sink to help keep any residual water in the gray tank from freezing.
      2. Pour a small amount of antifreeze into the black tank through the open toilet flush valve.
      3. Close the toilet flush valve and pour a dab into the toilet.
      4. If you installed a gray water transfer pump or any other optional plumbing system, be sure that they are fully drained or protected with RV antifreeze.

There are a lot more steps to winterizing your rig…. we just covered the ones relating to plumbing. Best source of additional winterizing info is your RV owner’s manual or RV dealer.

When the summer season gets ready to start, make sure that anything you disconnected is reconnected and that all hoses and water lines are visually intact and in good condition. Close any open drain valves. If you used antifreeze, flush it out according to the antifreeze manufacturer’s instructions. Now is a good time to sanitize your fresh water tank and system. Replace water filter cartridges with new ones. Refill the water heater. Apply pressure to the fresh water system and thoroughly inspect all plumbing connections and fixtures for leaks. If you did everything right at the start of the storage season, then your rig should be ready to go!

That’s It! A veritable flood of RV plumbing information! Did we get all your questions answered and concerns addressed?  I hope the above info helps you ‘stop the drip’ and keep all your RV plumbing leak free and functional!

This and additional related information can be found at:

121 Posts
January 1, 2016 – 10:49 am

The only thing I see missing is options. Like, 2nd bathroom, washer hookups, dishwasher, icemaker, aquahot (which would eliminate the water heater), but add lines going to various places in the floor for the radiator style floor heat.  But all-in-all, a very nice post here. Well written, easy to understand, crystal clear maps.

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