Preparing your plumbing for freezing temps in Seattle
Seattle winters are mild until they are not. When a cold snap drops below freezing for a few days, the pipes most at risk are the ones in unheated spaces: crawl spaces, garages, exterior walls and the hose bib on the north side of the house. Here is what to do before it happens.
Why freezing matters for plumbing
Water expands as it freezes. In a closed pipe that expansion has nowhere to go, so it pushes outward until a joint lets go or the pipe wall splits. The damage often does not show until the ice thaws and water pours out of the crack.
The pipes that freeze are almost always the ones in unheated or poorly insulated spaces: basements and crawl spaces, garages where the water heater lives, pipes running inside exterior walls, and anything outdoors.
Insulate exposed pipes
Foam pipe sleeves are cheap and quick to fit on any pipe you can reach in a crawl space, garage or basement. For pipes that have frozen before, heat tape or a self-regulating heat cable adds active protection. Pay particular attention to the cold supply into the water heater and any line that runs along an outside wall.
Disconnect and protect outdoor plumbing
Outdoor hose bibs are the first thing to go. Disconnect every hose, drain it and store it inside. If the hose bib has an interior shut-off, close it and open the bib to drain the stub. If it does not, an insulated faucet cover helps.
Older Seattle homes often still have standard hose bibs rather than frost-free ones. Replacing them with frost-free bibs, which put the valve seat inside the heated wall, is a small job that ends the annual worry. We do a lot of these in Magnolia and Wedgwood, where the originals are reaching the end of their life.
Keep water moving in a hard freeze
During the coldest nights, let the taps fed by exterior-wall pipes drip slightly. A trickle of moving water is much harder to freeze, and the open tap relieves pressure if ice forms anyway.
Keep the house warm and the cabinets open
Hold the thermostat steady, even when you are away, and never below about 55°F. Open the cabinet doors under kitchen and bathroom sinks on exterior walls so warm room air reaches the supply lines.
Seal drafts around pipe entries
Cold air leaking in around a pipe penetration is often what freezes that one pipe. Seal gaps around pipes where they enter the house, and around windows and doors in utility spaces, with caulk or foam.
When to call a plumber
If you have had a frozen pipe before, if the house still has galvanized or original supply lines, or if you cannot see where your pipes run, a short pre-winter inspection is worth it. We can point out the vulnerable runs, insulate them, replace standard hose bibs with frost-free ones and add shut-offs so you can isolate outdoor lines yourself next year.
Free estimates, same-day service available. Call (206) 708-3134.
Frequently asked questions
- What temperature do pipes freeze at?
- Water starts to freeze at 32°F, but pipes inside a house usually need several hours below about 20°F, or a long stretch just under freezing in an unheated space, before they freeze solid. In Seattle that means the risk is real during a multi-day cold snap, not on an ordinary frosty night.
- Should I leave a tap dripping?
- During a hard freeze, yes, for taps fed by pipes on exterior walls or in unheated spaces. Moving water is far less likely to freeze, and an open tap relieves the pressure that bursts a pipe if ice does form.
- What do I do if a pipe has already frozen?
- Turn off the main water shut-off, open the affected tap, and warm the pipe slowly with a hair dryer or warm towels, never a flame. If the pipe has split, or you cannot find the frozen section, call us. A burst pipe thaws into a flood.