Quick answer
Before the first hard freeze, shut off and drain your outdoor faucets, winterize lawn irrigation, test your main water shut-off valve, and insulate pipes in garages, crawl spaces and outside walls. Then check your water heater and sump pump. Most of this fall plumbing checklist takes an afternoon, and it heads off two of the most common winter problems: burst hose bibs and frozen pipes.
Why do plumbing prep in the fall?
Most winter plumbing damage starts with something small that was easy to fix in October: a garden hose left on the spigot, an irrigation line that never got drained, or a pipe in a cold garage wall. Once water freezes inside a pipe it expands, and the pipe can split. Often you don't find out until it thaws and starts spraying.
Fall is also when you still have mild days to work outside, and when plumbers' schedules are calmer than they are in the first cold snap. The ten steps below are in the order we'd do them.
1. Shut off and drain your outdoor faucets
Outdoor faucets (hose bibs) are one of the most common things to freeze. WSSC Water's winter advice is to close the indoor shut-off valve that feeds each outdoor faucet, disconnect the hose, and drain the line.
Even a frost-free hose bib can freeze if a hose is left attached, because the hose traps water in the valve body. Take every hose off, even if your spigots are frost-free.
- Find the small shut-off valve inside, usually in the basement ceiling or a utility room near where the faucet goes through the wall.
- Close it, then open the outdoor faucet to let the line drain. Leave the outdoor faucet open for the winter so any leftover water has room to expand.
- If there's a small drain cap on the indoor valve, open it over a bucket to empty the rest of the line.
- Coil and store hoses indoors. They last longer, and they won't trap water on the spigot.
- If you can't find an indoor shut-off for an outdoor faucet, that's worth fixing. Adding one, or switching to a frost-free sillcock, is a small job.
2. Winterize your lawn irrigation system
Sprinkler lines sit shallow in the ground and freeze easily. Shut off the irrigation supply, drain or blow out the zones the way your system's installer recommends, and protect the backflow preventer, which is the brass device where the system connects to your house plumbing.
For WSSC Water customers, lawn irrigation backflow assemblies need a field test every year, with results reported at spring start-up. The test must be done by a WSSC-licensed plumber who is a certified cross-connection technician. Fall is a good time to put that on the calendar for spring.
3. Find and test your main water shut-off valve
If a pipe bursts, the main shut-off is the difference between a wet floor and a flooded basement. WSSC Water recommends knowing where yours is and making sure it works before winter.
It's usually where the water line enters the house, often on a basement wall at the front of the home. Turn it slowly closed and back open. If it won't turn, turns but doesn't stop the water, or starts to drip at the stem, don't force it. Old gate valves can break when forced. Have it replaced with a quarter-turn ball valve before you need it in an emergency.
Show everyone in the house where it is. Put a tag on it.
4. Insulate pipes in cold spots
Pipes freeze where cold air reaches them: unheated garages, crawl spaces, attics, outside walls and under sinks on outside walls. The City of Rockville recommends sealing drafts, closing off crawl spaces, and wrapping exposed pipes with insulation or pipe sleeves.
Foam pipe sleeves from a hardware store are cheap and quick. For a pipe that has frozen before, a UL-listed heat cable is an option. Follow the instructions exactly, and plug it into a properly protected outlet. Keep garage doors closed when water lines run through the garage.
5. Give your water heater a fall check
Your water heater works hardest in winter, when incoming water is coldest. A few minutes now can catch problems early.
- Look around the base for water, rust or white crust. A small drip now usually gets worse.
- Find the temperature and pressure relief valve (T&P valve) on the side or top, with a pipe running down toward the floor. If that pipe is dripping or wet, have it checked. It can mean the valve is worn, or that pressure in the tank is too high.
- Check the temperature setting. The U.S. Department of Energy recommends 120°F, which it calls safe for most people, and it saves energy. A lower setting also reduces the chance of a scald.
- If your owner's manual calls for it, drain a few gallons from the drain valve at the bottom to flush out sediment. If the valve is old and plastic, be gentle; if it won't close fully, call us rather than leave it dripping.
- For gas water heaters, keep the area around the burner and vent clear. Don't store paint, gas cans or boxes next to it.
- Note the age (it's on the label). Many tank water heaters are near the end of their life somewhere past ten years. Planning a replacement beats an emergency on a cold morning.
6. Test your sump pump
Fall rain and winter thaws are when sump pumps earn their keep. Lift the lid, slowly pour a bucket of water into the pit, and watch the pump turn on, empty the pit, and shut off.
Warning signs: the pump hums but doesn't move water, it trips the outlet or breaker, it runs nonstop, or it's noisy. Also walk outside and make sure the discharge pipe isn't blocked by leaves or buried in mulch, and that it sends water well away from the foundation. If your pump is near the end of its life, replacing it in the fall is far better than finding out during a storm.
7. Check under every sink and around every toilet
Slow leaks hide in cabinets. With a flashlight, look for water stains, warped cabinet floors, corrosion on shut-off valves, and drips at supply lines. Turn each fixture shut-off a little to make sure it still moves.
Around toilets, look for water at the base or a rocking bowl. Both can mean a failed wax seal. Replace washing machine hoses that are cracked, bulging or more than about five years old. Braided stainless hoses are a cheap upgrade.
8. Plan for holiday cooking and guests
Kitchen drains and garbage disposals get their hardest workouts in November and December. Pour cooking grease into a can, not the sink. Keep potato peels, celery and other stringy scraps, coffee grounds, and bones out of the disposal, and run cold water while it's on.
If you have guests coming, fix the slow-draining shower or the toilet that runs now, while you have time.
9. Make a plan for trips and cold snaps
If you'll be away in cold weather, WSSC Water and the City of Rockville both say to leave the heat on and set no lower than 55°F. Rockville adds that shutting off the main water valve is another option for a long trip.
During a long cold snap, WSSC suggests letting a faucet drip while you're home to keep water moving, and opening cabinet doors so warm air reaches pipes under sinks. Rockville recommends the faucet farthest from the main valve.
10. Know what to do if a pipe freezes
- If you turn on a faucet and get little or no water in freezing weather, suspect a frozen pipe.
- Open the nearest cold-water faucet fully to relieve pressure (WSSC Water's advice).
- If you can see the frozen section, warm it gently with a hair dryer. Never use a torch, open flame or kerosene heater.
- Be ready to close the main shut-off. A pipe that froze can split and spray water as it thaws.
- If a pipe has burst, shut off the main first, then call a licensed plumber.
From our jobs
Montgomery County specifics
- Most of Montgomery County gets water from WSSC Water. Parts of Rockville are served by the City of Rockville, and many homes in the northern and western county are on private wells.
- The City of Rockville says property owners are responsible for calling a plumber to repair frozen or broken pipes on their property and inside their buildings.
- WSSC Water requires an annual field test for lawn irrigation backflow assemblies, reported at spring start-up, by a WSSC-licensed plumber who is a certified cross-connection technician.
- WSSC Water also says every hose bibb should have a vacuum breaker meeting ASSE 1011 or 1019. Many newer outdoor faucets have one built in.
Is this not for you?
Most of this checklist is homeowner work, and you don't need to hire anyone to drain a hose bib, test a sump pump or set a water heater to 120°F. Call a plumber when a valve won't turn or won't shut off, when a water heater is leaking or its relief valve is dripping, when a sump pump fails the bucket test, or when you find an active leak. If a sump pump keeps tripping an outlet or breaker, an electrician may need to look at the circuit too. For problems with a well pump or the well itself, call a licensed well contractor.
Frequently asked questions
When should I winterize my outdoor faucets in Montgomery County?
Before the first hard freeze, which usually means sometime in the fall. Don't wait for the first cold night. If you still need the hose on a warm weekend, you can always turn the indoor valve back on for a day.
Do frost-free outdoor faucets still need to be winterized?
Yes, at least partly. Always disconnect the hose, because a hose left on a frost-free faucet traps water in the valve and can split it. Shutting the indoor valve too adds protection, if your home has one.
What temperature should I keep my house at to avoid frozen pipes?
WSSC Water says to keep areas with water meters and interior pipes at or above 55°F, and to leave the heat on, no lower than 55°F, if you're away. During a deep cold snap, skipping big nighttime thermostat setbacks also helps keep pipes in outside walls warm.
Should I let my faucets drip at night?
During an extended cold snap, letting a faucet drip while you're home keeps water moving and can prevent a freeze. Choose a faucet on an outside wall, or the one farthest from your main valve. It uses very little water compared with the cost of a burst pipe.
Who pays to fix a frozen pipe, the homeowner or the water company?
Pipes on your property and inside your home are the owner's responsibility. The City of Rockville says this directly for its customers. The water utility handles its own mains and, in Rockville, frozen meters, so call your utility if you think the meter itself has frozen.
How often should I flush my water heater?
Follow your water heater's manual. Many recommend draining some water periodically to remove sediment. If you've never done it and the tank is old, have a plumber look first, because an old drain valve may not reseal.
How do I know if my sump pump is working?
Pour a bucket of water into the pit. The pump should start, empty the pit and shut off on its own. If it hums without pumping, runs constantly, or trips the outlet, have it checked before the next heavy rain.