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How to Get Bleach Into an RV Water Tank

Bleach is a very good cleaner of the water tanks on your RV. The chemical eliminates bacteria and odors, which is perfect for keeping your drinking water safe and your other tanks as clean as possible.

There are particular methods for adding bleach to an RV water tank. We want to help you add bleach and clean as safely and effectively as possible.

Bleach can be added to your RV water tanks in a couple ways. The answer really depends on which tank you are referring to. You’ll also want to take extra care in how much bleach you are adding.

How to get bleach into your freshwater tank

Let’s do a bit of a step by step here. First, using your RV manual or your memory, you need to know how many gallons your freshwater tank holds. You’ll want to prepare a quarter cup of bleach per gallon.

  1. Turn the hot water heater off in your RV. Wait until the water within the hot water heater cools down. Empty the hot water heater into your tank. The hot water heater itself should have a release for this purpose.
  2. Locate the freshwater tank on your RV. It should be underneath one of the sides. The cap will likely be blue or white. 
  3. Prepare your sewer hose and get it near the safety cap.
  4. Remove the safety ap and slide the hose on. Allow the freshwater tank to drain
  5. Remove the hose.

Now that the tank is empty, you can begin to refill it, but add your bleach first. Many RVs will have an exterior outlet to add liquids to all your tanks. If you have this, use it!

  1. Get gloves and a funnel. Bleach is not very safe for hands and will stain clothing
  2. Place the funnel in the outlet.
  3. Pour the right amount of bleach into the funnel. It will wash into the tank.

Then drain the tank and refill it.

How to get bleach into your black water tank

You might be familiar but the black water tank refers to the tank that catches waste from the toilet. The primary method of getting bleach in there is then the toilet.

The method is very similar to your fresh water tank, only it’s inside. Bleach is to be poured in the same ratio too, so you’ll need to know the size of your black water tank.

When you have your bleach prepared, do this step by step

  1. Drain the tank using a RV park receptacle. Bleach won’t help much if it’s not drained!
  1. Wear gloves!
  2. Pour the bleach down the toilet bowl. Flush if your RV requires flushing.
  3. Wait about ten minutes

It’s also important that you don’t plunge your toilet any time soon after pouring bleach in. Bleach can splash and burn your skin and eyes.

One word of caution, especially for the black water tank: Bleach does dry out the seals within your tanks. Don’t use it very often or consistently to avoid potentially damaging the tank itself.

How to get bleach into your gray water tank

The gray water tank takes the simple run off from your sink and shower. This one is pretty easy too.

First, find out the size of your gray water tank. Use ¼ cup per gallon.

  1. Get your sewer hose ready to drain the gray water tank.
  2. Remove the gap from the gray water tank. 
  3. Put the hose on the gray water tank
  4. Release the valve on the tank to drain it.
  5. Remove the hose and replace the cap

Inside, you can pour bleach down the shower drain or sink. The sink might be easier so you can avoid just pouring bleach on the shower floor.

Let this sit for a little while. Go out and repeat the proces for draining the tank, then refill it.

Your grey water tank might also have an exterior outlet like your fresh water tank. You’ll still want to drain it, but could again use the funnel to add the bleach to the tank.

Can I add bleach via the drain for the tanks? 

This is referring to the same outlets that allow you to train your tanks. This would definitely not be the easiest way to add bleach, as most loop down. The bleach would not work it’s way up to the upper parts of the tank where it’s needed.

Can I use bleach tablets?

If they fit in the outlet or drain, you could. Be sure that you are measuring these correctly so you don’t send too much or too little bleach into the tank.

Tablets might be safer for you because you are far less likely to spill them or splash with them by accident.

Check to see if it fits in the drain though before sending – you don’t want a bleach tablet getting caught in the pipe.


In many ways, bleach can be a helpful tool to clean our your RV tanks. It’s also quite often added the same way waste and water enter the tank. If your RV has convenient outside ports for adding liquid, that’s great – especially if you are in a nice weather area.

Bleach mostly requires a bit of patience. You don’t want it to stay in your holding tank so draining the tank out before and after use is essential. 

Bleach is also amongst other cleaners you can try in your tanks. Also consider using dishwasher detergent and other less harsh chemicals. This also depends on the purpose of your clean, of course.

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