Frozen pipes in rentals: prevention before a cold snap, and the call when one bursts

A hard freeze produces the same calls every year: no water from one faucet, then water through a ceiling once the pipe thaws. Most of them can be prevented with a message to tenants and a walk around each building before the cold arrives. The rest go better when whoever answers the phone already knows the first three things to say.

Why pipes burst

Water expands as it freezes, and the American Red Cross notes that the pressure can break metal or plastic pipes regardless of their strength. The break often stays hidden while the pipe is frozen solid. It shows up when the ice melts and water flows again, which is why the flood call tends to come the morning after the coldest night, not during it.

Which pipes freeze first

The Red Cross points to pipes exposed to severe cold, such as outdoor hose bibs, pool supply lines and sprinkler lines, then supply pipes in unheated spaces: basements, crawl spaces, attics, garages and kitchen cabinets, plus pipes along exterior walls with little or no insulation. The U.S. Department of Energy adds a less obvious one: insulating heating ducts in an unheated space can make nearby pipes colder, because they lose the heat they used to get.

Use the list to mark the risky spots in each building once, in daylight. A note on the property that says “kitchen sink on the north wall, crawl space under unit 1” turns a vague freeze warning into a two-minute walk.

Before a cold snap: the tenant message

Send this a day or two before temperatures drop below freezing:

Every line in it comes from Red Cross guidance. Keeping the thermostat at the same temperature day and night costs a little more in heat and saves a much larger repair. A trickle of cold water through an exposed pipe helps keep it from freezing. And 55°F is the Red Cross floor for a home left empty in cold weather.

Before a cold snap: the building walk

• Remove and drain outdoor hoses, close the inside valves that feed outdoor hose bibs, then open the outside bibs so leftover water can drain
• Drain pool and sprinkler supply lines the way the installer directs, without adding antifreeze unless told to
• Insulate exposed pipes in garages, crawl spaces and under cabinets
• Check that crawl space vents and garage doors close
• Make sure every tenant and vendor knows where the main water shut-off is, and that it turns
• Check the heat works in vacant units, and set it to at least 55°F

The preventive maintenance checklist puts these on the fall calendar, so they happen before the first forecast instead of during it.

Vacant units and tenants who travel

Empty homes freeze first, because nobody notices the heat went out. For every vacant unit during a freeze, someone checks the thermostat and looks under the sinks at least every few days, and after any power outage. If a unit will sit empty all winter, ask a plumber whether to drain the system.

Ask tenants to tell you when they will be away for more than a few days in winter. The ask is simple: leave the heat at 55°F or higher, open the cabinet doors on outside walls and leave a number where they can be reached.

When a tenant says the water stopped

A faucet with only a trickle in freezing weather usually means a frozen pipe that hasn’t burst yet. Treat it as urgent. The Red Cross steps, in the order to say them:

1. Keep the faucet open. Water running through the pipe helps melt the ice.
2. Warm the section of pipe with an electric heating pad, a hair dryer, a space heater kept away from anything that burns, or towels soaked in hot water.
3. Never use a blowtorch, a kerosene or propane heater, a charcoal stove or any open flame.
4. Keep warming it until full water pressure comes back.
5. Check every other faucet in the home. If one pipe froze, others may have too.

If the frozen spot can’t be found or reached, or it won’t thaw, a licensed plumber goes out the same day. Ask the tenant to find the main shut-off now, in case the pipe splits as it thaws.

When a pipe bursts

• Shut off the main water valve first, then call
• If water is near outlets, fixtures or the electrical panel, keep everyone away and shut off power only if it is safe to do so
• Send a plumber, and a water mitigation company if water reached floors, ceilings or walls
• Photograph everything before cleanup, for the owner and the insurer
• Dry wet materials within 24 to 48 hours; the EPA says that in most cases mold won’t grow if they are dried in that window

After the water is off

The second day decides the cost. Wet drywall, insulation and flooring that dry within 24 to 48 hours usually avoid mold, according to the EPA. If mold does appear, the EPA says a patch smaller than about 10 square feet can usually be cleaned up as a normal job, while larger growth or heavy water damage calls for its guidance on professional cleanup. Record the shut-off time, the mitigation start time and the drying readings on the work order, so the owner and the insurer see the same timeline.

Then find out why it froze. A pipe that bursts once on an outside wall will burst again next winter unless someone insulates it or reroutes it. The post on stopping repeat repairs has a way to catch it.

Where Now Ours fits

You decide what counts as an emergency. An emergency calls and texts the first person on your on-call calendar, then your backup after 5 minutes. Ours answers tenants at any hour in your company’s name and asks the safety questions you set, such as whether water is near an outlet. The after-hours call script has the same questions if a person answers instead.