Frozen pipes in Salt Lake City
Salt Lake City International Airport averaged 32.1 nights a year at 20°F or colder over 1991-2020. Over 2016-2025 it averaged 16.4. Warmer winters sound like good news for pipes, and mostly they are. The catch is that a house that hasn't frozen in three years is a house where nobody drained the sprinkler line.
Nights per year at 20°F or colder, Salt Lake City airport
Why 20°F
Field tests by the Building Research Council at the University of Illinois found that uninsulated pipes in an unheated attic began to freeze when the outside temperature fell to 20°F or below. It is a rule of thumb, not a guarantee: wind, gaps in insulation and a pipe on an outside wall can freeze above it. Northern builders usually keep pipes out of unheated space, which is why the threshold matters most in houses where someone ran a line through a garage or a crawl space.
How cold, and when
- The season. Over 2016-2025 the first fall freeze at the airport came on average around October 28 and the last spring freeze around April 4.
- The hard freezes. December through February average 15.6 nights at 20°F or colder between them.
- The long ones. The longest run of days that never got above freezing was 24 days, January 3, 2004 to January 26, 2004. The record low is -30°F on February 9, 1933.
- The trend. 2024 had 7 nights at 20°F or colder and 2025 had 10, against 56 in 2013.
The benches and the canyon mouths, from the East Bench to Cottonwood Heights and Sandy's Granite foothills, run colder at night than the airport on the valley floor.
Which pipes freeze first
- Hose bibs with a hose still attached.
- Sprinkler lines and backflow preventers that weren't blown out.
- Supply lines in exterior walls, especially behind kitchen and bathroom sinks.
- Pipes in garages, crawl spaces and unheated basements.
- Lines to a swamp cooler on the roof that weren't drained in the fall.
Before a cold snap
- Drain and blow out the sprinkler system and disconnect hoses in October.
- Insulate exposed pipes in garages and crawl spaces.
- On a night forecast in the teens, open the cabinet doors on outside walls and let a faucet drip.
- Know where your main shutoff is before you need it.
- If you travel, keep the heat on and have someone check the house.
If a pipe froze
Turn off the water before it thaws if you can, open the faucet, and warm the pipe slowly with a hair dryer or a space heater you stay with. If it already split, shut off the main and call. Frozen and burst pipe cleanup.
Questions Salt Lake homeowners ask
At what temperature do pipes freeze in Salt Lake City?
Field tests by the University of Illinois Building Research Council found that uninsulated pipes in an unheated space began to freeze when the outside temperature fell to 20°F or below. Pipes can freeze above that in wind, or where insulation has gaps. In Salt Lake City, that usually means pipes in exterior walls and garages, or in a crawl space or unheated basement.
Should I let my faucets drip in Salt Lake City?
On nights forecast in the teens or colder, a slow drip on faucets fed by pipes in outside walls helps, because moving water is harder to freeze and a drip relieves pressure. Most nights in the valley don't need it.
When should I blow out my sprinkler system?
Before the first hard freeze. Over 2016-2025 the first fall freeze at the airport came around October 28 on average, earlier on the benches.