How to Winterize a Vacant House

Water that freezes in a pipe expands and can split it, and in an empty house nobody is there to notice the leak when it thaws. There are two ways to protect a vacant house through a cold season: keep it heated, or drain the water out of the plumbing so there is nothing left to freeze. The two can also be combined.

Option 1: keep the heat on

The American Red Cross says to leave the heat on, no lower than 55°F, when you will be away in cold weather, and to keep the thermostat at the same setting day and night. State Farm, Chubb and Arlington County, Virginia, give the same 55°F floor. Insurers that write commercial vacant buildings vary: Philadelphia Insurance gives a 55°F minimum, and The Hartford says to keep interiors above 40°F to protect water-filled piping.

• If the heat runs on oil or propane, keep the tank full. HUD’s 2016 guidance for vacant FHA properties required a “keep full” contract with a local supplier where the heat had to stay on.
• Heat alone depends on the furnace and the power staying on. A temperature alert or a monitored sensor tells you if it fails.

Option 2: drain the plumbing

If the house has an automatic fire sprinkler system, PEMCO Insurance says to leave it on. Ask a sprinkler contractor before you shut off or drain any water that feeds it.

1. Shut off the water. Close the main shutoff valve, usually in the basement, near the water heater or in a utility closet. One utility, Louisville Water in Kentucky, suggests tagging the valve with a waterproof tag or ribbon so it is easy to find. HUD’s 2010 guidance for vacant FHA properties on public water had the utility shut it off at the curb.
2. Turn off the water heater. Shut an electric unit off at the breaker. Turn a gas unit to Off and close its gas valve. Drain it according to the manufacturer’s instructions.
3. Drain the lines. Open every faucet and spigot, hot and cold, and leave them open. Purdue Extension says to drain the whole system by disconnecting pipe unions or joints near the main valve, and to drain toilet tanks. A guide published by the City of Hopkins, Minnesota, recommends blowing the lines out with an air compressor.
4. Protect the traps. Water stays in every sink, tub and floor drain trap. Purdue Extension says to add propylene-glycol antifreeze to each trap, about as much as the water in it. Use only the non-toxic RV type, usually pink. Purdue warns that ethylene glycol (automotive) antifreeze is not safe in any part of a home water system.
5. Drain the appliances. Drain the washing machine and dishwasher pumps; Purdue says not to put antifreeze in them. Check the ice maker and any humidifier, and cut power or fuel to every water-using appliance.
6. Outdoor lines. The Red Cross says to close the inside valves that feed outdoor hose bibs, remove and drain the hoses, and leave the outside valve open so leftover water can expand. Drain sprinkler lines following the installer’s directions; don’t put antifreeze in them unless the directions say to.
7. Well systems. Drain the pressure tank.
8. Label it. Post a sign such as “Winterized: do not use plumbing” where anyone coming in will see it, and leave a note at the electrical panel. Winterizing has to be carefully reversed before anyone moves in.

HUD’s 2016 guidance also required a pressure test of the water lines when an FHA property first became vacant, to document their condition.

Keep checking

A winterized house still needs visits. HUD’s 2010 guidance called for checking that the sump pump works, and its 2016 guidance required re-winterizing when the first winterization stops being effective. Look for leaks, a stopped furnace and signs of entry on each visit. The Vacant Property Checklist lists what else to look at, and Estates and Long Vacancies walks through an inherited house left empty over a winter.