How Much Bleach to Sanitize an RV Water Tank?

How much bleach to sanitize an RV water tank varies from one cup per 40 gallons of water tank capacity to one cup per 60 gallons, depending on who you talk to. We recommend one cup per 50 gallons, just to make the math easier. Otherwise, it doesn’t really hurt your RV to add more bleach if you want to kill everything possible.

How Much Bleach to Sanitize an RV Water Tank?

Most RVers recommend 1 full cup of bleach for every 50 gallons of water tank capacity. Thus, if your water tank can hold 100-gallons of water, use 2 cups of bleach. If your tank holds 25 gallons, use 1/2 cup.

Some RVers recommend going more light at 1 full cup for every 60 gallons of water tank capacity, Others recommend more strong, at 40 gallons of capacity. It just depends on your preference, your peace of mind, and how foul your tank is.

Read our other article, “How to Sanitize an RV Fresh Water Tank“.

Will it Hurt My RV if I Use Too Much Bleach?

Not really. Because you’re only going to leave the bleach solution sit for 8 hours or more, it doesn’t affect the plastic water tank, the Pexate pipes, or the even the water pump itself. You can go with something more strong, maybe 2 cups for every 50 gallons, or 3 cups, and not hurt anything at all.

Keep in mind that bleach itself comes in a plastic jug and it often sits on a shelf for years in some households, and it doesn’t seem to hurt the jug, nor does it seem to hurt a washing machine either.

Am I Using Too Little Bleach?

Interestingly, there’s no such thing as using too little bleach when it comes to sanitizing an RV water tank.

The point is to have “safe” water in your water tank, not 100% disinfected water. It’s nearly impossible to completely kill every living organism in an RV water tank just by pouring bleach or something else into it. Instead, you just want water that won’t make you sick and is still tolerable to drink. How much bleach that will be is completely up to you.

Some RVers actually add a tablespoon of bleach to their water tank at every refill just for good measure. Bleach at this low level is perfectly safe to drink, and you probably won’t even notice it. In fact, many water districts add a light amount of bleach just to kill off pathogens at a small degree. If you swam in a swimming pool, you’ve already ingested or absorbed bleach.

If you believe your water tank is heavily polluted with bacteria and algae, then certainly use more bleach. It won’t hurt any part of your RV to do so. You should not drink this water considering how much contamination it already has. This is a case where you want to set it for several hours and drain.

Can I Use Any Kind of Bleach?

Get common household liquid bleach. Clorox Beach in a one-gallon jug (see it on Amazon) is perfect. Any brand will do as long as it’s regular household liquid bleach.

Do not get “Cleaner plus Bleach”. Do not get scented bleach.

What if You Have Too Much Algae in Your Water Tank?

In that case, you may have to remove your water tank and do a more thorough job of cleaning it by hand. It’s possible you may want to take your RV into a shop and have a new water tank put in. It’s not uncommon for full time RVers to get a new tank once every 4-5 years.

How to Test if My RV Water Tank is Clean

The best way, and easiest way, is fill a clear glass with water, hold it up to sunlight, and see what it looks like. If it looks hazy, yellow, or green, then you know its time to sanitize. Otherwise, if the water looks clear and it smells clean, it’s safe for drinking.

If the water looks white, then that just may be aerated water, caused by the water pump or air in the lines. Just let the glass of water sit for a minute to let all the bubbles disappear. Then look at it for color and give it a sniff.