Plumbing Winterization: RV Antifreeze Method

If you choose to winterize the plumbing system yourself, you will need a few tools and supplies and approximately 2 hours of free time.

There are two methods used to winterize an RV: compressed air or RV antifreeze. The RV Antifreeze method uses RV-approved non-toxic, portable antifreeze.


  • 4-6 gallons of RV non-toxic antifreeze. DO NOT USE Automotive Anti-Freeze. Automotive antifreeze is poisonous and not for use in potable water systems.


  1. Remove the low-point drain caps for the water lines and open all the faucets and outside shower if equipped to allow the lines to drain.
  2. Open the drain valve for the fresh water tank and allow it to drain completely.
  3. Verify the water heater is turned off on both gas and electric.
  4. Remove the water heater drain plug and open the pressure relief valve to let air in the tank and allow it to drain. (If your unit is equipped with a tank-less water heater, please refer to the operator’s manual for the winterization procedure.)
  5. If you have a water filter, remove and discard the water filter cartridge. Drain the water from the base and reinstall. If equipped use the bypass tube for cartridge filters.
  6. Empty the waste water holding tanks at an approved wastewater dump station.
  7. Turn the water heater bypass valves to the bypass position. The bypass valves are located on the water lines entering the back of the water heater. Depending on the model of RV you own, you may have to remove an access panel to reach the bypass valves. The easiest way to locate the by-pass valves is to locate the water heater on the outside of the RV. The by-pass valves will be located on the backside of the water heater on the inside of the unit or in the basement storage compartment.
  8. If your RV has a residential refrigerator the ice maker water line should not be winterized with antifreeze. Simply drain the line along with the rest of the water lines, but do not add antifreeze.
  9. Install a bypass hose on the suction side of the water pump and pull directly from the anti-freeze container. Your RV dealer can provide you with the necessary hose and fittings to do this. Some RVs may be equipped with the pump by-pass. In that case, simply locate the loose end of the by-pass hose and put it in the jug of antifreeze. Turn the by-pass valve handle to align with the by-pass hose.
  10. As an alternative, if you cannot bypass the pump— use this method. Once the water has drained from the fresh water tank, close the drain valve and pour at least 4 gallons of RV non-toxic antifreeze into the fresh water tank to fill the tank enough to allow the water pump to draw the antifreeze. The use of a long funnel may be helpful.  Add more antifreeze as needed to keep the level above the minimum operating level.  It helps to slope the unit towards the suction side of the tank.
  11. After the water has drained from fresh water tank, reinstall the low point drain caps and close the faucets and any valves open in the freshwater system.
  12. Turn the water pump switch and open the cold water side of the faucets one at a time until anti-freeze comes out.
  13. Repeat Step 12 opening the hot water side of the faucets.  Remember to do the same for the outside shower or kitchen, if you have one.
  14. Flush the toilet until antifreeze begins to flow into the bowl and allow about one quart of antifreeze to go down the toilet to winterize the black tank.  Leave a small amount of antifreeze in the toilet to cover the seals.
  15. Don’t forget the outside shower or kitchen if equipped.

If equipped with a washer hookup follow these steps:

  1. If there is a washer hooked up, turn the washing machine on to the fill cycle using a cold water setting until anti-freeze appears, then repeat using a hot water setting and until anti-freeze appears.
  2. If there is no washer hooked up, open the cold and then hot valves until antifreeze appears.

Pour about one quart of RV antifreeze into each drain, p-trap, and toilet. Leave a little antifreeze in the toilet to maintain the air seal. Don’t forget the washer drain if equipped.

Once the water is removed from the water lines, water heater, and fresh water tank it’s a good idea to reinstall the drain caps and plugs and close the valves to keep critters out of the fresh water system.