How to Winterize your RV with Antifreeze


  • 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 on ½" tasteless water hose 

Step 1: Drain the Fresh Water Tank 

  1. To find the drain, first locate the fresh water fill 
    • The fresh water will be inside the trailer at the point of fill 
    • Some RV's 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 outside of the RV below the water fill or perhaps under the RV on a stanchion coming down through the floor 
    • 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 
  2. Open the drain and let all the water flow out 

Step 2: Drain the Water Heater 

  1. Turn off the 110-volt element in your water heater 
    1. Switch the wall switch AND the switch on the water heater itself to the "off" position 
  2. Locate the drain plug 
    1. Usually on the bottom of the tank, inside the water heater access door, on the outside of the RV 
    2. Using your 1/2" ratchet drive, remove the drain plug. 
      • 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 
    1. If your unit has a drain cock instead of a plug, it will look like an automobile radiator drain 
      1. Turn the drain clockwise to open 
      2. Pull the "pop-off" valve to the straight-out position 
      • "Pop-off" valve is the brass valve at the top of the outside face of the water heater 

Step 3: Drain You Plumbing System 

  1. Locate the 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 in 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 
  2. Open all sink and shower faucets in the RV 
    • This will allow most of the water in the system to drain 
  3. After all lines have finished draining, turn on the water pump and run it for five minutes 
  4. Check to see if your water pump has a filter screen mounted on the intake side of the pump 
    • 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: Connect the Antifreeze to the Water pump 

  1. Disconnect the fresh water inlet hose from the water pump 
  2. Connect the 5' length of water hose to the pump where you just removed the water tank inlet line 
  3. 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 5: Install By-Pass Kit 

  1. Install by-pass kit, as per directions on the kit 
  2. 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 6: Pump in Antifreeze 

  1. Turn on Pump 
  2. Open each faucet in the RV and let the water run until it turns the pink color of the antifreeze 
  3. When you have finished this, re-connect the water hose to its original position and switch off the water heater by-pass valve 

Step 7: Antifreeze Drain Traps 

  1. 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 8: Drain Holding Tanks 

  1. Dump your black tank first, then the grey tank 
    • Water in the grey tank helps flush solids and septic residue in the flexible hose line 


  1. Fill your water tank and flush the water lines until the water runs clear.
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