RV Water Storage Tanks – What You Need To Know

RV Owners

Few things are as important as the state of your RV water storage tanks. In fact, I don’t think it’s overstating matters to say that the safety of the water you drink, and the safety of the wastewater you store and dispose of have a more direct effect on your health than just about anything else in your RV. You’ll want to clean and use your water storage tanks properly to be sure you are safe and in good health. But do not fear! You’ll learn how to do exactly that in this post.

How to install an RV water storage tank

First, you should know about the three RV water storage tanks you’re going to need – a black water tank, a gray water tank, and a freshwater tank. The black water tank holds the wastewater from your toilet. The gray water tank holds all other wastewater from your RV – water that goes down the drain in sinks and the shower. The fresh water tank, of course, holds all the water you’re going to use to drink and wash, etc. 

Begin by deciding what kind of material your holding tank should be made of. Plastic, polyethylene, and ABS are the most commonly used materials. Next, figure out where your plumbing fixtures are. Fit the black water tank directly to your toilet. Install your freshwater tanks in a central location that makes it easier to hook up to the sink, shower, and toilet. Make sure the gray water tanks are placed between the sink and shower. 

Install your tanks according to the manufacturer’s instructions. The size of your tank should be enough to supply you with water on your travels, but should also fit your measurement allotments and RV specifications. When you’re planning how to install your tanks, keep in mind how big they are. If you’re installing larger tanks than were there before, make sure you have additional support bars to support the weight and size of those tanks. 

How to sanitize RV water storage tanks

To sanitize your RV water storage tank, drain the water heater first. Release the pressure relief valve, then open the drain on the bottom left-hand corner. Locate the low-point water drains and open them so the water can completely drain. Find the freshwater tank and drain it. Use a water pump to force all of the water out. When water stops coming out of the tanks, don’t forget to turn the pump off or it could get damaged. Close all the drains once you’re done. Then, refill your tanks with a mixture of bleach and water – 1c of bleach to every 15 gallons of water. Fill your tank almost all the way, then drive around for a bit to let the water slosh into every nook and cranny it possibly can. Let the water sit in your tank, then open all the faucets and let the water drain out. You should be able to smell the bleach in the system. Leave it for at least 12 hours. Once the tank is completely drained, refill it with water, and drain it again. Continue refilling and draining the tanks until you can no longer smell bleach in the system. 

A few other things of note – you’ll want to sanitize your RV water storage tanks at least once a year. Only use white non-toxic hoses to fill your storage tanks. Other hoses may leach chemicals into your water. Bring along a garden hose for flushing your system or washing your RV, but use only the non-toxic hose to fill your tanks with the water you’ll actually use. Also, you’re going to want to buy a filtration system if you don’t already have one. The filter will keep debris out of your storage tank and can remove bacteria and even lead from your water. You can install an inline filter directly in the kitchen sink, or you can filter the water going into your RV. You’ll want to filter all of your water, not just drinking water, to be sure your showers are clean and your dishes are being washed safely. 

Refilling your tanks

Depending on how long you’re boondocking, you may need to refill your tanks. Try to figure out how many gallons of water you’ll use per day, so you can calculate when you need to refill. Portable water tanks can be useful as well if you don’t want to have to break camp to head and refill. When you do refill, use your own white hose and filter to prevent contamination. Keep your white water hose separate from any other hoses, and keep the ends locked together when it’s not in use. If possible, store it in a sealable bag. The extra few steps it takes to keep your holding tanks clean are hugely important to keep your water safe.

Dumping and flushing tanks

Eventually, you’ll need to dump and flush your holding tanks. Here’s how to do it: 

  1. Always empty the black water first. You need enough flow to empty the black water properly, so wait until it’s almost full it empties easily. Don’t forget to use gloves and check the connection to the drain before starting.
  2. Open the valve and dump the waste. 
  3. Drain the gray water next. If you only have one hose, doing this will clean the muck left by the black water. After draining the gray water, rinse the hose with clean water (but not with your white hose – keep that separate at all times!)
  4. To get your black water tank completely clean, pour some softener into the empty tank. Two cups of softener mixed with one gallon of water should do it. 
  5. Use a bacterial digestant to treat your black water. 

Treating your tanks for storage

When you’re getting ready to winterize your RV, or store it for long periods of time, drain all the water from your holding tanks. It might take a while, but the alternative is moisture trapped in the system, which causes slime, algae, mold, and other problems. 

Happy travels!

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