How Much Bleach To Sanitize RV Water Tank?

The great thing about RVs is being self-sufficient and traveling to places without regular amenities. It means that you can travel at very short notice to places about which non-RV owners can only dream.

RVs have sleeping accommodation, cooking facilities and food storage, cooling, sewerage, and potable water systems.

Water that has not been consumed should only be kept in the RV water tank for a maximum of two weeks, and every six months, the RV water tanks should be bleached with 1 ounce of bleach for every 40 gallons of water; this will ensure that mold, mildew, and bacteria do not build up.

For each RV system to continue operating efficiently, you should clean and check them regularly. In particular, this applies to the RV water tank, where if you allow unused water to stay in the tank, you stand the risk of mold, mildew, or bacteria building up, which is why you need to sanitize your RV water tank thoroughly.

How Much Bleach Do You Need To Sanitize The RV Water Tank?

Of all the cleaning and sanitizing jobs that need to be completed in an RV, cleaning the RV water tank and black water system is probably the most crucial.

An RV tank filled up with water from many different places when you do not know the quality or origins of the water; must be kept in a state that cannot compromise your family’s health.

Twice a year, or more often, if the water starts tasting strange or comes out cloudy, you should sanitize the RV water tank.

There are unique formulations of liquid designed to make sure your RV water tanks remain clean and sanitized; however, regular kitchen bleach is just as, if not more effective.

Work out the capacity of your RV water tank (this usually is available in the handbook which came with your RV) and measure out 1 ounce (1 ½ tablespoon) of bleach for every 8 gallons of water. For example, if your RV has a water tank that holds fifty gallons of water, you would use 6 ¼ ounces (12 tablespoons) of bleach.

How Do You Sanitize The RV Water Tank?

The bleach must only ever be poured into the tank as part of a diluted water mix. Never run the bleach directly into an empty RV water tank. Doing so may damage the seals, gaskets, and plumbing fittings.

The following step-by-step procedure details the process to follow.

Preparation And Emptying The RV Water Tank

  1. Have everything at hand before you get started. It is tough having to stop what you are doing and rush into the house or to the store to find a missing tool.
  2. Turn off the water heater and drain the water from the RV water tank. You must switch off the RV’s water tank heater because the damage will occur if it continues to operate with no water.
  3. Once the current to the water heater is turned off, close the input valves to the water heater and open the outlet valves to allow the water to drain from the RV water heater.
  4. Shut the icemaker off and close the valve to it.
  5. Sanitise the funnel you will use to pour the “bleached” water into the RV water tank.
  6. Mix the bleach into a 10-gallon container and mix it well. Bleach is a powerful sanitizing agent, so do not be tempted to add more than the calculated amount of bleach into the RV water tank.

Filling And Cleaning The RV Water Tank

  1. If you have a 50 gallon RV water tank, pour 20 gallons of freshwater into the tank.
  2. Pour the contents of the “bleach mix” bucket into the tank.
  3. Top the tank up with fresh water until it is full. You can typically tell it is full because water will start pouring out of the overflow pipe.
  4. One at a time, turn on the faucets in the RV and run them until you smell the “bleached” water through the system; this makes sure that any organisms which may reside in the pipes are disinfected.
  5. Don’t worry about smelling the bleached water; this will go away when you finish the process.
  6. Take the RV for a drive after the bleached water has been poured into the system. The bumps in the road allow the water to splash into any nooks and crannies and ensure the whole system gets exposed to the sanitizing agent.
  7. It is recommended that you allow the bleach to do its magic overnight or for at least 12 hours.


Resetting And Refilling The RV Water Tank

  • Once the waiting period is over, empty the bleached water from the RV water tank.
  • Refill fresh water into the RV water tank.
  • As you did with the bleached water, you should now turn on all the faucets and flush the toilet to run the fresh water through the system until you cannot smell the bleach anymore. Doing so will clean out any remaining bleach from the RV water tank, and the smell will dissipate.
  • If you can still smell the bleach after flushing the system, repeat the process by emptying the RV water tank and refilling it with more freshwater.
  • If your RV water system has a filter, now is an excellent time to replace it with a new one.
  • Finally, refill your water heater if you have one (each RV water heater is a bit different, so it’s a good idea to follow the manufacturer’s directions.)

If these steps don’t remove any musky smell or odor from the water system, try starting from scratch and follow the whole process once again.

In the improbable event that there is still a problem, it is time to consult your dealer or RV specialist.

If you sanitize your water tanks regularly and you trust the water source, there is no reason why you shouldn’t use water from the system for cooking and drinking purposes. If you are not sure of the water quality from the RV park, you can always install a good quality water filter.


Sanitizing your RV water tanks is not an optional extra for people suffering from OCD; it is a necessary part of RV ownership and must be done regularly.

Using one ounce per gallon of water in the RV to sanitize the water will ensure that your water is safe and clear of any unhealthy organisms.

Good luck, and happy camping!

Check out our article on: How To Use Black Tank Flush System?

Please keep in mind that we may receive commissions when you click our links and make purchases. However, this does not impact our reviews and comparisons. We try our best to keep things fair and balanced, in order to help you make the best choice for you.

As an Amazon Associate, I earn from qualifying purchases.