How to Prevent Frozen Pipes in Madison, WI

Madison winters are no joke. When temperatures drop below 20°F — which happens regularly from December through February in Dane County — unprotected water pipes can freeze within hours. A frozen pipe that bursts can release hundreds of gallons of water into your home, causing tens of thousands of dollars in damage.

The good news: frozen pipes are almost entirely preventable. Here's what every Madison homeowner needs to know before the first hard freeze.

Why pipes freeze in the first place

Water expands as it freezes. When that expansion happens inside a sealed pipe, the pressure can exceed 2,000 psi — enough to split copper or crack PVC. The pipe itself doesn't always burst at the frozen spot; the pressure wave travels through the water column and can cause a failure several feet away from where the ice formed.

In Madison homes, the most vulnerable pipes are those in exterior walls, unheated crawl spaces, garages, and attics. The age of your home matters too — older Madison houses built before the 1970s often have pipes in locations that would never be approved by modern code.

The 5 most vulnerable pipes in your Madison home

• Pipes running through exterior walls — especially on the north and west sides
• Pipes in unheated crawl spaces or basement rim joists
• Supply lines to hose bibs (outdoor faucets)
• Pipes in attached garages, especially supply to a utility sink
• Any pipe within 12 inches of an exterior foundation

How to prevent frozen pipes: the complete checklist

Before the season (October–November)

• Disconnect and drain all garden hoses — a connected hose traps water in the bib
• Shut off the interior valve to outdoor hose bibs and open the exterior bib to drain
• Insulate pipes in crawl spaces, unheated garages, and near exterior walls using foam pipe insulation (available at any Madison hardware store)
• Seal gaps around pipes where they pass through exterior walls — a can of spray foam works well
• Have your heating system serviced — a furnace failure during a polar vortex is when frozen pipes become emergencies

During cold snaps (below 20°F)

• Open cabinet doors under kitchen and bathroom sinks on exterior walls to allow warm air circulation
• Let a trickle of water run from faucets connected to vulnerable pipes — moving water resists freezing
• Keep your thermostat at 55°F minimum, even when away — never turn it off entirely in winter
• If your garage has a water supply, keep the garage door closed

If you're leaving for more than 3 days

• Keep heat at 60°F minimum
• Have a neighbor or friend check the house every 24–48 hours
• Consider shutting off the main water supply and draining pipes if you'll be away longer than a week
• Install a smart thermostat with remote monitoring — you'll get an alert if the temperature drops

What to do if a pipe freezes

If you turn on a faucet and get little or no water — especially after a cold night — you may have a frozen pipe. Act immediately:

1. Locate your main water shutoff valve and know where it is before you need it
2. If water is actively flowing from a burst pipe, shut the main valve immediately
3. Open the affected faucet — this relieves pressure as the ice melts
4. Apply gentle heat with a hair dryer or electric heating pad — never use open flame
5. Start from the faucet end and work back toward the frozen section
6. If you cannot locate the frozen section or water is not flowing after 30 minutes, call a plumber

When to call a professional

Call Madison Plumbing Pros immediately if: water is flowing from a burst pipe, you cannot locate the frozen section, the pipe is inside a wall, or you've thawed the pipe but have no water pressure. We respond 24/7 and can be at most Madison addresses within 90 minutes.