Western Washington winters are mild most of the time, which is exactly why a cold snap does so much damage here. Buildings are not designed for long stretches below freezing, pipes run through uninsulated crawl spaces and exterior walls, and a week of arctic air arrives with a few days' warning. The Insurance Institute for Business & Home Safety (IBHS) identifies burst pipes as the leading cause of property damage from winter weather. This guide covers what to do before the first hard freeze, what to do during one, and the policy conditions that decide whether a loss is paid.
Why pipes burst, and where
When water in a pipe freezes, the ice blockage itself is usually not where the pipe fails. Pressure builds between the blockage and a closed faucet or valve, and the pipe splits at its weakest point. The leak often appears only when the ice thaws, sometimes hours later and in a different room.
The pipes most at risk are the ones you see least:
Unheated spaces
Crawl spaces, attics, parking garages, mechanical rooms and exterior storage closets.
Exterior walls
Kitchen and bathroom supply lines on outside walls, especially on north-facing sides.
Vacant units and suites
Spaces between tenants where the heat has been turned down or off.
Fire sprinkler piping
Wet systems depend on building heat. Branch lines in stairwells, entries and attics freeze first.
Before the first freeze
- Service the heating system. Have boilers, furnaces and unit heaters inspected and tested before you need them. A heating failure during a freeze is how most large losses begin.
- Insulate and seal. Wrap exposed pipes in unheated areas. Seal gaps where pipes, cables and vents pass through exterior walls so cold air cannot reach the plumbing. Where insulation alone is not enough, a licensed contractor can install listed heat tracing.
- Find and label the shutoffs. Every on-site manager and maintenance tech should know where the main water shutoff and the sprinkler control valves are. Tag them, and post a simple map in the maintenance office.
- Disconnect hoses and winterize irrigation. Drain hose bibs and blow out irrigation lines. A hose left attached traps water in the faucet body.
- Clear the roof drainage. Clean gutters, downspouts, scuppers and roof drains so rain and snowmelt can leave the roof. Blocked drainage adds weight and pushes water under the roofing.
- Have the sprinkler system checked. Ask your fire protection contractor to confirm that dry-pipe systems are drained at the low points and that any antifreeze loops are tested.
- Add temperature monitoring. Low-temperature sensors in vulnerable areas, tied to your alarm monitoring or sending alerts to a phone, give you warning while there is still time to act.
Vacant units need their own plan
An empty apartment or suite is the highest-risk space in the building in winter, because no one is there to notice a problem. IBHS recommends keeping unoccupied spaces at a minimum of 55°F and making sure the temperature never falls below 40°F. For each vacant unit:
- Leave the heat on and set to at least 55°F. Do not let a departing tenant's utility account close without transferring service.
- Open cabinet doors under sinks on exterior walls so warm air reaches the pipes.
- Walk the unit on a set schedule, more often during a freeze, and keep a log.
- For a space that will be empty for a long period, consider shutting off the domestic water and draining the lines. Fire sprinkler lines are separate and must stay in service.
During a cold snap
- Send tenants a short notice: keep the heat on even when away, open cabinet doors under sinks, let a thin stream of water run from faucets on exterior walls, and report any loss of heat or water pressure right away.
- Check vacant units, mechanical rooms and garages daily.
- Keep entries and walkways treated for ice, and record when you did it. Slip-and-fall claims rise with every freeze. See our guide to slip, trip and fall prevention.
- If the power fails, heat fails with it. Know in advance which buildings have backup power and which will need the water shut off if an outage runs long.
If a pipe bursts
- Shut off the water at the nearest valve or the main.
- If water is near electrical panels or fixtures, cut power to the area before anyone enters.
- Call a water mitigation company. Drying that starts within the first day limits the damage and the risk of mold.
- Photograph and video everything before cleanup, including the failed pipe. Keep the damaged section.
- Report the claim promptly. Call us and we will help you report it to the carrier and line up the adjuster.
The coverage conditions to check now
Most commercial property policies cover sudden water damage from a burst pipe, but two conditions regularly cause trouble after a freeze loss.
Heat and freeze conditions. Many policies cover freezing losses only if you took reasonable care to maintain heat in the building, or shut off the water and drained the system. Thermostat settings, vacant-unit logs and service records are how you show that you did.
Vacancy provisions. Many commercial property policies limit or remove coverage for water damage and certain other causes of loss once a building has been vacant for a stated period, often 60 consecutive days. How "vacant" is defined varies, and a building with too little occupied space can qualify even with a few tenants in place.
Also confirm that your policy includes loss of rents (business income) for the time units cannot be occupied, and ask how water backing up through drains is treated, since that usually requires an endorsement. Whether a particular loss is covered depends on the policy's terms, conditions and exclusions, so review the wording with us before winter and not after a claim.
When to call a broker
Call us before a building or a large share of its units goes vacant, before a renovation that takes heat or sprinklers out of service, or if you are unsure how your policy treats freezing, vacancy or lost rents. Learn more on our apartment building insurance page, or read our guide to water damage prevention.