Before we get into how long to keep fresh water in RV tank, we’d like to clarify something for the newbie RV traveler that there are 3 types of RV water tanks: Gray water tanks, black water tanks, and freshwater tanks.
Freshwater tanks are what this post is mainly about. These tanks hold the water that comes out of your taps, sinks, and showers.
Freshwater is also your drinking water, so when talking about draining and clean freshwater we are referring to keeping your drinking water healthy as well.
You can also opt to buy bottled water for your trips, especially if you plan on renting, or taking a short trip.

How Long To Keep Fresh Water in RV Tank?
You can keep fresh water in an RV tank for two weeks. The two-week rule is meant for people who aren’t using their water during that time.
I like to dump our tanks after every trip, then refill them before I go back on the road so as not to really worry about it too much.
Water does get undrinkable. Water left sitting for too long can taste horrible, but more importantly, it can be unsafe and contaminated.
Water sitting dormant in a plastic tank for two weeks can grow algae, mold, and bacteria. But, if you maintain your bank the chances of matters getting extremely bad is low.
Related: Illnesses Related To Bacteria In Freshwater
How Do I Keep Water Fresh In My RV Tank?
Although it’s the least intimidating holding tank of them all, the freshwater tanks still need to be maintained.
Pay attention to the weather to prevent water stagnation. Insulate your hose during freezing cold weather and drain in really hot weather.
Keep it clean before it starts to smell but if it is already contaminated use bleach to clean the tank.
Related: How To Keep RV Fridge Cold While Driving?
How To Use Bleach To Clean Fresh Water RV Tank?
- Pour 1/4 cup of bleach per 15 gallons of water.
- Run the water until you smell bleach. Then run the water until all the bleach is gone.
- Let rest for about 24 hours
- Refill your tank and run until bleach s gone.
- Enjoy!
Additional Ways to Keep Stored Water Usable:
- Use High-Quality Water
- Get A Filter
- Use A Clean Hose
- Get Rid of Odd Odors in Your Sinks
- No Food Down The Drain
Should The RV Water Pump in My RV Be Turned On?
RV water pumps should only be turned on when you are dry camping and using water in your freshwater tank. If you are hooked up to city water or RV park water, the water pump should be turned off.
Related: Best RV Sewer Hose
How Much Water Does a Fresh Water Tank Hold?
The capacity varies in different makes and models of RVs. Modern fifth wheels and large travel trailers typically have at least 60-gallon freshwater tanks.
How Do You Know The Water Isn’t Fresh and Usable?
- Bad smelling water
- Foul tasting water
- Color change
- Clogging
- Not Properly Chlorinated
Related: How to Get Rid of Poop Pyramid
Keep It Fresh, Keep It Clean and Enjoy The Ride
Now we know How Long To Keep Fresh Water in RV Tank because you need water for drinking, cooking, washing, brushing teeth, feeding pets, and feeding plants.
So, for the best results and to avoid algae, parasites, mold, fungus, and bacteria keep your water tank clean and don’t leave your freshwater tank stagnant for over two weeks.
Simply, keep it germ-free and be happy!