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Family Fun RV – How To Winterize Your RV


How To Winterize Your RV

The steps listed below will familiarize you with the process of winterizing your RV, either by blowing out all the water lines with compressed air, or by replacing the water in the lines with non-toxic antifreeze. Choose the process that works best for you.

Winterization with Air

Supply list

  • A compressor capable of maintaining 100 PSI minimum output
  • City water inlet hose thread to air hose quick connector adapter
  • ½” drive ratchet with long extension and sockets
  • One gallon of non-toxic antifreeze
  • Shop towel or rags to wipe up splattered water
  • Channel Lock Pliers

Step 1: Drain the fresh water tank. To find the drain, first locate the fresh water fill. The fresh water (or potable water tank, as it is sometimes referred to) will be inside the trailer at the point of fill. Some RVs have sub-floor water tanks, but they will always be located by the water fill location. If your tank is inside your RV, the drain may be at the base of the tank (on the tank itself or at the end of a short plumbing line), on the outside of the RV below the water fill, or perhaps under the RV on a stanchion coming down through the floor.

If your tank drains slowly, you may wish to look for water line drain outs and speed up the process by opening the drains and turning on your water pump. Most pumps can move approximately 3 gallons per minute, so you can drain a 40-gallon tank in about 13 minutes.

If the water tank is in an insulated sub-floor, the drain will usually be located on the bottom of the tank under the RV. (Some tank drains are routed out through the main frame of the RV and are hidden behind the wheels.)

Step 2: Drain the Water Heater. First, turn off the 110-volt element in your water heater. To do this, switch the wall switch AND the switch on the water heater itself to the “off” position. (If you have a 1994 or newer unit, the “on-off” switch may be on the outside of the water heater, tucked under the control valve.) Next, locate the drain plug; usually on the bottom of the tank inside the water heater access door, on the outside of the RV. Using your ½” ratchet drive, remove the drain plug. The drain plug will be either plastic or metal. Be sure to use the proper size socket on the drain plug, because some drain plugs are very tight.

If your unit has a drain cock instead of a plug, it will look like an automobile radiator drain. Turn the drain CLOCKWISE to open. Next, pull the “pop-off” valve to the straight-out position. (The “pop-off” valve is the brass valve at the top of the outside face of the water heater.) This will relieve the vacuum in the water heater tank and allow it to drain.

Step 3: Drain your plumbing system. Locate your low point drains if your RV is so equipped, and open them. To find your low point drains, follow your plumbing lines through your RV. The drains will have pull- up “T” valves if they are inside the RV. Some RV’s have low point drains outside, under the unit. These outside drains will be either two 90-degree valves, or two lines with caps or plugs. Next, open all sink and shower faucets in the RV. This will allow most of the water in the system to drain.

After all lines have finished draining, turn on the water pump and run it for five minutes. This will clear out the fresh water tank-to-pump pickup line. Check to see if your water pump has a water pump filter screen mounted on the intake side of the pump. If it does, simply turn the screen housing counter-clockwise to open. The purpose of this step is to drain the screen housing. After all water is removed, re-assemble the pump screen housing. If your unit has a water filter, a winterize plug was provided at the time of purchase. Remove the filter and install the plug.

Step 4: Blow out your water system. Connect your compressor to the city water inlet with the air-to-water hose adapter. Go through your RV and close all faucets and drains, leaving only the kitchen “cold” side open. (Hang a damp wash rag or shop towel over the faucet to reduce water splattering.) When all water is blown out of that line, open the “hot” side of the kitchen faucet. Then, with both “hot” and “cold” faucets open, close the “cold” side of that faucet. Repeat this procedure for the bathroom sink, the shower, the toilet valve, and the outside shower (if your unit is so equipped). Always leave at least one faucet open, so as not to build up excessive pressure in the water system.

On units with single mixer faucets, you can simply switch from “cold” to “hot” and no other faucet has to be open during that process. To aid in holding the toilet valve open, simply open the flush valve and insert a short piece of 2” x 2” wood directly into the flush opening. Let the valve close on the 2” x 2”, and this will keep the water flush valve in the open position.

Finally, remove the water heater drain plug and blow out any water that may have collected in the bottom of the water heater. Also, re-open the low point drains and make sure no water remains down in the stanchions. Replace the water heater and drain line caps or plugs. (All drain plugs should now be tightly in place.)

Step 6: To keep the sink drain traps from freezing, pour three cups of non-toxic RV antifreeze down each drain. Be sure to do all three; the kitchen sink, the bathroom sink, and the shower drain.

Step 7: Drain the holding tanks on your RV. To de-winterize your RV, simply fill your water tank and run the water pump until water has recirculated throughout the entire water system.

Winterization with Antifreeze

Supply list

  • Two gallons of non-toxic RV antifreeze
  • Paper towels or shop rags to wipe up small spills
  • A water heater by-pass kit, on the water heater water inlet line
  • A 5’ length of ½” tasteless water hose

Step 1: Follow steps 1 through 3 from “Winterization with Air” directions

Step 2: Disconnect the fresh water inlet hose from the water pump. (This is the lead from the fresh water tank.) Connect the 5’ length of water hose to the pump where you just removed the water tank inlet line. Secure the 5’ hose with the same clamp that was used on the original hose. Place the other end of the hose in one of the two gallons of antifreeze.

Step 3: Switch the water heater by-pass valve to the “by-pass” position. (If you neglect this step, you will fill up your water heater with antifreeze, adding six to ten more gallons of antifreeze to your shopping list.)

Step 4: Turn on your water pump. Open each faucet in the RV and let the water run until it turns the pink color of the antifreeze. When you have finished this, re-connect the water hose to its original position and switch off the water heater bypass valve.

Step 5: Follow steps 6 &  7 from “Winterization with Air” directions. To de-winterize your RV, fill the fresh water tank and flush the water lines until the water runs clear.

Your RV is now winterized and you should be ready for the cold. If you have any questions, or are unable to winterize your unit yourself, our Service Department does offer this service for a nominal fee.