Monday, August 8, 2022


Time to de-winterize and sanitize the RV water system

By Mark Polk, RV Education 101
March is a safe time to start RV spring preparation checks for some RV owners. A good place to start is de-winterizing the RV plumbing system. Depending on how the RV was winterized, the RV water system needs to be de-winterized and sanitized. Note: Make sure the freezing temperatures are over for the season before you do.

Here is what you do

The first step is to flush all the non-toxic RV antifreeze out of the RV plumbing system. On average you used 2 to 3 gallons of RV antifreeze to winterize the unit. The best method is to flush the RV antifreeze out by running fresh potable water through the water system. You can do this through the city water inlet or the fresh water holding tank using the water pump. Open all of the faucets (hot and cold) and run fresh water through the system until it flows clear. All remnants of the antifreeze will go into the holding tanks and can be emptied at a dump station later.

Drain any RV antifreeze from the fresh water holding tank prior to adding potable water to the fresh water tank.

Properly dispose of antifreeze

Note: You need to decide the best method for draining and disposing of the RV antifreeze. Most RV antifreeze is biodegradable and safe for the environment, but you should check before disposing of it. You can drain the antifreeze into a large bucket and then properly dispose of it.   

Was the water heater bypassed when the RV was winterized? If not, you need to drain the antifreeze from the water heater too. This can be 6 or 12 gallons of antifreeze depending on the size of the water heater tank.

Drain all the antifreeze, then close all the drains.

If the hose was removed from the outside shower, reconnect it.

To remove antifreeze from the 12-volt water pump, add potable water to the fresh water holding tank, turn the pump on and open all water faucets. Run water through the system until it runs clear and then turn the pump off.

Take the water heater out of the bypass mode and connect your drinking water hose to the city water inlet. Turn the water on and open all water faucets (hot and cold). Run fresh water through the plumbing system for several minutes. Don’t forget the outside shower if equipped. It will take a couple of minutes to fill the water heater tank before water flows out of the hot water faucets.

Fill and flush the toilet. Add some additional water to the black water holding tank and treat it with a holding tank treatment so it is ready for use.

Reinstall any water filter cartridges you removed prior to winterizing the RV.

With pressure on the system, check the plumbing system for leaks.

The RV is de-winterized! Now, to sanitize the water system

At this stage of the RV spring preparation process, I like to sanitize the water system. It’s not difficult to do – just follow these simple steps.

Take a quarter cup of regular household bleach for every fifteen gallons of water that your fresh water tank holds. Mix the bleach with water in a one-gallon container and pour it into the fresh water holding tank. Note: Make sure it is regular household bleach – not all bleach disinfects.

Fill the fresh water tank completely full of potable water.

Turn the 12-volt water pump on. Open one hot and cold faucet at a time and run the water until you smell the bleach at each faucet.

Close the faucets and let it sit for at least 12 hours.

Drain the entire system and refill the fresh water tank with potable water.

Open all the faucets and run the water until you no longer smell any bleach. When all signs of bleach are gone it is safe to use your RV water system.

Tip: It’s also a good idea to use a water filter at campgrounds and keep bottled water on hand for drinking.

To learn more about de-winterizing your RV and getting it ready for camping season check out our RV Winterizing & Storing your RV video course.



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1 year ago

Rv still buried with snow; guess not time to de-winterize just yet. I don’t use the Rv pink stuff I use air to blow out lines have never had an issue with freezing lines. Pump, sink trap lines and hot water tank are drained too.

Bob P
1 year ago

There are a few false items here, I never use RV antifreeze as I blow the water out of the system for winterizing, when sanitizing the system you speak of installing the water filter then adding bleach, with our motorhome there isn’t a gravity fill for the fresh water tank. The tank is filled by turning a valve at the fresh water connector, I don’t install my new filter elements until the sanitation operation is complete, instead I add bleach into the empty filter housing, reinstall the cap and turn the valve to fill the tank and start the filling. I don’t want to contaminate my filters especially the activated charcoal final element with bleach. Just a point for the RVers who don’t have gravity fill ports.

Jerry Chandler
1 year ago
Reply to  Bob P

I was just about to post about not installing the filter till after you flush the system. Good post Bob!

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