Service Lines and Deep Frost

Why it happens

Water service lines are buried to stay below the frost, but long, very cold stretches with little snow cover can drive frost deeper than usual. Lines under driveways and sidewalks, where snow is cleared, are most at risk because snow normally acts as insulation.

The warning signs

Pressure drops slowly over a cold day and then the water stops completely. Nothing in the house runs, even though the neighbors may still have water. That pattern points to a frozen service line or meter rather than a single pipe indoors.

What to do

Check with the city that the outage isn't on their side. Then close the main valve inside and open a faucet so you'll hear when water returns. Don't try to thaw a buried line yourself; it needs specialist equipment.

Thawing a service line

Plumbers can thaw service lines with electric thawing machines, hot water jetting or steam, depending on the pipe material. Electric thawing isn't safe for every type of pipe, so the plumber needs to know what yours is made of.

Afterward

Once water flows, check the line where it enters the house and the meter area for leaks. Ask the plumber whether insulating or relocating part of the line would help.

Get help

If the whole house is dry in a cold snap, see frozen pipe repair.

Prevention

Leaving snow on the ground over the line, rather than clearing it, helps insulate it. During an extreme cold spell, a slow drip from one faucet keeps water moving through the service line. If your line has frozen before, ask the plumber about insulation at the shallowest point.

More plumbing guides

• Winterizing a Pocatello Home
• Finding the Water Shut-Off in a Basement or Crawl Space
• Reading the Water Heater Label
• Is There a Leak? Check Your Meter
• Checking an Idaho Plumbing License