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For many, the best part of camping in a recreational vehicle (RV) is the full-service plumbing contained within. There’s no doubt that the ability to wash dishes, take showers, and use the restroom are luxuries many people refuse to forgo while camping. RV plumbing works as it should most of the time, but it could end your campout when it doesn’t.

What type of plumbing do RVs use, and what do you need to know about the systems? 

Inside of a high-end RV bathroom with a sink and a shower.
RV bathroom | Getty Images

The Drivin’ & Vibin’ team tells us that modern RVs use a combination of PEX tubing to supply the potable water system and PVC piping to carry wastewater away. 

An RV’s water system starts with onboarding potable water, usually from a municipal water source which either pressurizes the water system or fills the RV’s potable water tank and uses the onboard water pump. Once the water system has water pressure, faucets, showers, and toilets work much like they do at home.

The difference between Grey Tanks and Black Tanks in RVs

Wastewater operation ultimately depends on facilities provided at the RV’s camping site. Modern RVs feature two types of onboard wastewater tanks. The “Grey Tank” holds wastewater from sink and shower drains, while the “Black Tank” holds anything that flushes down the toilet. The end of a camping trip culminates in a trip to the campground’s “Dump Station” to drain the wastewater into an approved sewage system. Some RV sites have “Full Hook-Ups (FHU) that eliminate the need for stopping at the dump station. 

Common RV plumbing problems 

The Drivin’ & Vibin’ team tells us that the most common RV plumbing problems include pressurized water system leaks and clogged wastewater tanks. 

An RVs pressurized water system involves a network of hot and cold water supply lines running to every faucet, toilet, and outside spray port. These lines contain fittings and connections prone to failure or loosening, causing water leaks as the RV bounces down the road and survives extreme temperature ranges.  

Wastewater storage tanks become clogged when misused. Unlike most household kitchen sink plumbing, most RV plumbing doesn’t have a garbage disposal, so disposing of food scraps down the sink drain is ill-advised. 

Also, there is a trade-off when it comes to flushing number-twos. Using more water when flushing helps move things along when dumping the black tank, but tank storage is limited, so using more water will fill it up faster. 

A word of caution concerning FHU operation: It’s OK to leave your grey tank valve open while on FHU, but leave your black tank valve closed until the tank is almost full, or it’s time to go. Leaving the black tank valve open allows water to seep out, leaving behind a pile of difficult-to-remove solids.

RV plumbing repair: DIY, or call a pro?


3 RV Campgrounds in the Smoky Mountains

Being your own repair person is a valuable skill for anyone, especially anyone who owns an RV. If you have to call a pro to fix every minor issue, you will have a lot of ruined camping trips and more extensive vacations in your RV. 

Some plumbing problems are minor and only require using your hand to tighten a leaking fitting. Or a clogged black tank may require pouring a bucket of hot tap water into an open toilet to flush out solids and toilet paper accumulated in a pyramid shape directly below the entry point.

Axel Addicts reminds us that special tools and skills sometimes make the job easier. Whenever you lack the proper tools or skills, calling in a pro is the right choice. 

The good news is that you are not alone. A quick search of the internet reveals many other RVers who had the same problems, often offering advice on DIY solutions or when to call a plumber.