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How An RV Water System Works

People need three things to survive: shelter, food, and clean water. RVers have the luxury of traveling on even the most remote reaches of the highway with all three – assuming you picked up food at the last stop!

If you own a mid-sized motorhome or larger, it probably came from the manufacturer with fresh- and waste-water tanks included. An RV water system includes three separate tanks: drinking water, black water (sewage), and grey-water (dirty water). Besides being portable, these systems work much the same way your home water systems do, though RV tanks require more hands-on maintenance.

So let’s get into the nitty-gritty of how exactly these tanks work, and how you can keep yours working for road trips to come.

Three Separate Water Tanks

Most RVs have three separate water tanks. One of these is a reservoir full of water for drinking, bathing, and washing. The other two hold different types of wastewater that need to be dumped.

Potable Water Tank

The potable water tank is your mobile reservoir, holding fresh, clean drinking water. This is the water that your system pumps into the shower, sink faucets, and toilet.

Black Water Tank

The black water tank holds exactly what you would expect it would. It contains everything that goes down the toilet.

This tank will also hold the used shower and sink water if you don’t have a gray water tank.

This water has to be drained at a designated septic clean-out. These are located at RV campgrounds, rest stops and rest areas, RV dealerships, and some gas stations.

Gray Water Tank

The gray water tank holds used water that isn’t quite as foul as sewage water. This is the water that drains from the sinks and the shower.

This relatively clean wastewater usually contains bath and dish soap, as well as kitchen runoff like oil. This wastewater is legal to drain directly into the ground in some states, though it is important to double-check local laws before draining your tank.

How It All Connects

Most motorhome fresh water tanks have an outdoor fixture that can connect to a city water supply. Most RVs only have one hose fitting, and it is compatible with a standard garden hose. There are some RVs that have 2 hose fittings.

As you fill the holding tank with fresh water, keep an eye on the overflow tub. This will tell you when the tank is full.

Be sure to turn the overflow valve off if you are hooked up to a continuous water supply so that you don’t leak water from your pressurized system.

Water Pump

If you’re boondocking or not hooked up to continuous water, then you’ll be using your water pump. Most RV manufacturers install freshwater tanks with a 12-volt pump that pulls water from the tank on demand.

The water pump is usually hooked up to the faucet so that the pump will activate and deactivate automatically at the turn of a faucet.

Some systems are manual and require you to turn on the pump each time you want freshwater drawn from the tank while not hooked up to city water.

The line that supplies the water heater continues throughout your rig to supply hot water for cooking, bathing, and washing. A cold water line supplies flushable water to the toilet. Meanwhile, all water lines drain to the gray water tank.

Cleaning A Camper Water System

The most important benefit of having a water system onboard your RV is having access to clean drinking water. Naturally, to keep your water squeaky clean, you’re going to want to routinely maintain and sanitize your water tanks.

Let’s focus on your RV’s freshwater tank for now, since this is the most important part to keep clean. You’ll know your potable water tank is past due for a sanitation treatment if you smell a foul odor or an unusual taste from the water coming out of your faucets.

Fortunately, disinfecting your RV’s freshwater tank is one of the easiest chores. All you need is some household bleach.

Basically, all you have to do is drain your water tank, refill with a bleach solution, and drain again. Refill the tank with water to rinse the tank of any leftover bleach and drain it again. Now you should be ready to fill the tank with drinking water for your next trip.

Do I Have To Clean My Black And Grey Water Tanks?

Yes, your wastewater tanks do need to be maintained. However, they are a bit easier to maintain and do not need to be cleaned as frequently as the fresh water tank that houses your drinking water.

The process for cleaning black and grey water tanks is fairly straightforward. Essentially, what you do is empty the tanks, then pour all-purpose cleaner down the toilet and sink, followed by water. Allow this to drain, and your system should be clean.

Be sure to refer to your user manual for complete instructions specific to your rig.

In Summary

Hopefully, this article has revealed how those unseen water tanks work in your RV. Remember that they are all connected, so be sure to properly maintain each one.

Water is one of the most important resources out there, especially when you’re camping in the boondocks. Be sure you’re keeping your water tanks maintained so that you have a reliable source of water, no matter where you are.

Maintenance is fairly straightforward, but there is a lot of variety between camper models.

When in doubt, contact your manufacturer or RV dealer to be sure your RV plumbing systems are running and are squeaky clean.

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