All About RV Plumbing: What you Need to Know About Parts and Fittings

Last updated on April 4th, 2019 at 11:22 am. Originally published on June 27th, 2018

Running water may seem pretty basic. And there’s no doubt about it, it’s one of the fundamental things that makes RVing such a comfortable and flexible way to travel.

Your RV plumbing system allows you to bathe, perform basic household cleanup, wash your own dishes — and, best of all, completely avoid using public toilets. But just because it’s such an essential feature of your motorhome doesn’t mean it’s intuitive, and learning some basic RV plumbing information can help you keep everything working ship shape (and avoid a costly repair bill if something minor goes wrong).

In this post, we’ll walk you through the basic parts and fittings of your RV’s plumbing system, and tell you what you need to know about how to maintain your pipes and fittings so everything goes with the flow. After all, when you’ve gotta go, you’ve gotta go — so read on to learn how to keep things moving.

How Does RV Plumbing Work?

Depending on the make, model, size, and type of RV you have, your rig may or may not have a completely self-contained plumbing system including toilet facilities, sinks, and a shower. (Some smaller models and sleepervans forego an indoor restroom to save space, for instance, a problem some campers circumvent by investing in a portable, stand-alone camping toilet.

For the purposes of this post, we’ll focus on RVs that have a comprehensive water system including both potable and waste water holding tanks, as well as a water heater.

Your RV’s water tanks live underneath the chassis, and allow you to bring a portable supply of fresh water as well as carry waste water when you’re not hooked up to city systems. In other words, your RV’s water tanks are what enable you to go off-grid for dry camping or boondocking adventures — and, in fact, it’s usually the fresh water supply that’s the limiting factor when it comes to how long you can stay out there. (Here are some smart ways to conserve water when you’re on the road… and always.)

Your potable water tank has a well-marked hose inlet connection that allows you to fill it from a city water source, or to connect for open-ended fresh water usage (such as at a hookup site at a campground). However, you shouldn’t just hook up a regular old garden hose to your fresh water tank, since they’re not food-grade and can add unpleasant tastes and odors to your supply.

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Potable water hoses are both affordable and easy to find. (Here’s a hint for when you’re at the store: they’re always white in color.) By using one, you’ll avoid adding any noxious chemicals to your drinking water, and also help keep your freshwater tank in great working order in the long run.

It’s also a good idea to use a water pressure regulator when connecting to fresh water, since too much force can wreak havoc on your RV’s sensitive plumbing system. Although many campgrounds regulate their sites’ water pressure at the source, this way, you’ll have a failsafe just in case (or if you’re filling up from a non-campground city spigot).

RV Plumbing Basics

Once water is on board your RV, it journeys back out again in a variety of ways.

In some cases, it drains down your galley sink, bathroom sink, or shower — in which case, it heads to the gray water holding tank. Gray water is dirty, used water that contains soap, food particles, and other contaminants, but not human waste. Thus, in some states, it’s not considered a biohazard and is actually legal to dump on the ground — though we still highly recommend you avoid this practice. Soap and other chemicals can devastate local plant life, and besides, it’s just plain gross.

The water you flush down your RV’s toilet goes to the black water holding tank, which, as the name implies, is the ickier of the two wastewater supplies. Black water must always be dumped into a city sewer system at a dedicated dump site, which you’ll find at most developed campgrounds.

Although dumping your tanks may seem intimidating at first, it’s actually really simple and totally mess-free if you do it right. Just invest in a quality RV sewer hose and make sure you’ve got the water lines and fittings synced up nice and tight (but not over-tightened). With the tools modern RVers have at their disposal today, dumping your tanks is basically as simple as flipping a switch.

RV Pipe Leak

In most cases, the basic knowledge of your RV’s plumbing fittings described above will be all you need to know for day-to-day operation of your rig’s water system.

But in some cases, you may discover an internal RV pipe leak that keeps things from running smoothly.

Depending on your skill level and experience with general, basic repairs — as well as the extent and cause of the damage — fixing your RV’s plumbing problem may be as simple as replacing a basic fitting, such as your fresh water inlet port or waste outlet valve. However, some of your pipes may be deep within the body of your RV, and if you’re not an expert repairman (or woman), it might be a better idea to recruit professional help. Yes, hiring an RV mechanic can be costly and time-consuming, but there are trustworthy, reliable professionals out there if you know what to look for. (Here’s our guide.)

RV Plumbing Parts

The specific plumbing fittings in your rig will vary depending on your model’s specific set-up and size, but many are the same kinds of plumbing parts you’d find in your household system. However, in an RV, the plumbing system is generally composed of PVC as opposed to metal, so make sure you purchase RV-specific parts if you need to replace something.

Looking for more information about travel trailer parts and accessories that’ll make your camping trip even easier? Check out the following posts here at the RVshare blog.

This post may contain affiliate links.

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