Friday, December 2, 2022


It’s time to clean your fresh water tank


By Russ and Tiña De Maris

If your RV has been sitting “in the mothballs” all winter and you’re readying it for travel season, don’t neglect the fresh water tank. It only takes about one mouthful of “yecchh!” water to convince you that water can go stale. What’s to do? Well, this is the same trick we recommend when you buy an RV prior to using it.

water-742You’ll need to completely drain your fresh water holding tank, and run the water pump until all water is out of the system. If your water heater is “in the circuit” (meaning not winterized, but holding water) drain it too, using the drain cock on the heater. Of course, you’ve shut it off first.

Determine the fresh water tank’s capacity — easy if you have the rig’s owner manual. If not, locate the fresh water tank and measure it. Break down the feet and inches to decimals, i.e., a 4′ 6″ run is 4.5′. Multiply the height, width, and depth figures to come up with total cubic feet of capacity. Now multiply the capacity times 7.48051945, which is the conversion factor for cubic feet to gallons.

With gallon capacity on hand, drag out the household bleach — NOT the scented variety. In a clean container (a one-gallon cleaned juice jug is ideal) pour 1/4 cup of bleach for every 15 gallons of tank capacity. Top off the jug with clean, fresh water.

Be sure your fresh water drain valve is closed (and the water heater if applicable), and pour this bleach solution into the holding tank. Now completely fill the fresh water holding tank with clean, fresh water. At this point if you can, move your RV around the block to thoroughly swish and mix the solution in the tank.

Now turn on the water pump and pump the bleach solution through all the plumbing. You’ll know when you’ve pumped enough as you should smell the bleach solution at the fixture. Let solution stand in the plumbing and fresh water tank overnight. Next day, drain the fresh water tank (and again, water heater if applicable), and refill the fresh tank with clean, fresh water. If you’re concerned about the chlorine taste or odor, mix up a solution of 1 quart of cider vinegar for every five gallons of tank capacity and dump it in the fresh tank, repeating the same process you did for the bleach job.


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6 years ago

Is it ok to fill the hot water tank with the water and bleach solution?

6 years ago

We do the same thing. However getting the bleach mixture from the bucket to the tank can be challenging. Here is how I overcame this. I put some clean water in the tank. Then I disconnect the hose at the spigot and with a premeasured amount of bleach in a measuring cup, I pour it slowly into the hose. I hook the hose back up to the spigot and fill up the tank. I like running a bleach solution thru the hose I will use at the park.

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