Dewinterizing An RV’s Plumbing

After being cooped up through a long, cold winter, spring blossoms and warmer weather energizes RVers. Our thoughts inevitably turn toward getting our RVs ready for takeoff.

A Toyota SUV towing a lightweight trailer on a mountain road. Photo: Bruce W. Smith.
Photo: Bruce W. Smith

Before hitting the road for that first outing, one essential task must be completed: Dewinterizing your RV. It’s necessary maintenance for RVs that have set idle over the winter months. It’s a normal aspect of owning an RV in regions of the country where temperatures dip below freezing.

Winterizing an RV water system boils down to draining water from the plumbing, water heater and holding tanks. Next, you pour non-toxic RV anti-freeze into sinks, drains, and toilet to protect susceptible plastic components. These include P-traps and low points in the lines, which can be damaged by standing water freezing during the winter.

Dewinterizing an RV’s plumbing is simply reversing everything in the winterizing process so the RV is ready for camping. We should mention this process focuses solely on dewinterizing an RV’s plumbing system. The general maintenance, checking systems, cleaning, etc. are a story for another time.

The Basics Of Dewinterizing An RV’s Plumbing

A winterizing compartment on an RV. There is a hose attached to the filler, and various levers to aid in the process. Photo: Bruce W. Smith
Photo: Bruce W. Smith

“There are basically two tasks in dewinterizing any RV,“ says master RV technician Tony Salazar of Carrier RV Service in Eugene, Oregon. “One is to refill the water system and bleed it of air, while flushing it to remove all traces of anti-freeze. The other is thoroughly checking the entire plumbing system (and water heater) to make sure there are no leaks, cracked filters, or other damage so the RV is mechanically ready for camping.”

Salazar says a first-time RV DIYer should be able to accomplish dewinterizing an RV in less than an hour.

Salazar approaches the task by closing all the low-point drain valves. He makes sure the drain plug is reinstalled in the water heater, the heater is off, and the bypass valve closed. Next, he removes the aerator screens from faucets and shower heads and closes all faucets.

This is also the time to replace the trailer or coach’s water purification filter(s). These filters are removed during the winterization process, and new are ones installed during dewinterizing.

Bleed The Water System

The next step to dewinterizing an RV is to recharge the RV’s water system. This is accomplished by hooking up to a water supply, turning on the RV’s water pump, and then turning on the water heater.  

Next, slowly open each faucet, cold and hot, one at a time, for a couple minutes to bleed out any air trapped in the lines. Start in the galley and then go to the bathroom(s). Let the water flow through the entire system until there’s no air coming out. Do the same with any exterior water fixtures.

An RV sink with running water to help bleed the system of air. Photo: Bruce W. Smith
Photo: Bruce W. Smith

Make sure the dump valve on the blackwater tank is closed, then flush the toilet multiple times to push the antifreeze out of the P-trap. Run the shower for several minutes for the same reason.

Note: This is also a good time to open the graywater tank valve open and drain the tank into the sewer. The dewinterizing process may fill it quickly as the RV’s water system is charged and flushed.

Check For Water Leaks

During this filling/flushing part of dewinterizing an RV it’s important to carefully inspect every filter and shutoff valve for leaks. This includes those at the toilet, under the sinks, at the water pump, the water filter and water heater. Don’t forget any that are located under the RV.

“I’ve had numerous customers that do the winterization themselves who miss something, and then that item becomes an issue during the dewinterizing process,” says Salazar.

“For example, they forget to drain the water filter and empty the little pre-filter feeding into the water pump. When the temperature dips below freezing, the water in those filters turns into a block of ice and cracks the filter.”

Dewinterizing an RV plumbing system is one of the simpler maintenance tasks of being an RV owner. All it requires to do properly is to pay attention. That way, a water leak won’t put a damper on your spring outings. 

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