A Frozen Pipe Split: Drying the Walls Before Mold Gets a Start

By John Calhoun, owner of Mold Remediation Gettysburg PA · Updated October 24, 2026

When a frozen pipe splits, shut off the water, photograph the damage, find how far the water went and get it dry within 24 to 48 hours, the window the EPA gives for preventing mold. A lot of Gettysburg houses were plumbed long before anybody insulated a wall, and January here gets cold enough to find out which pipes are exposed. The twist with a winter break is that the water usually ran somewhere you can’t see. Do that and a burst pipe is a plumbing bill and some drywall, not a mold job.

The first hour after the pipe breaks

1. Shut off the main water valve. Know where it is before you need it. The Pennsylvania Insurance Department’s winter guide puts it plainly: learn how to shut the water off if your pipes freeze.
2. Keep clear of wet electrical. If water came through a ceiling near a light fixture or ran down a wall with outlets in it, turn that circuit off at the panel if you can reach it from a dry floor. If you can’t, call an electrician.
3. Open faucets to drain what’s left in the lines.
4. Photos and video before cleanup. The Insurance Department says to photograph the damage inside and outside, call your insurer right away, and make only temporary repairs until the adjuster has looked.

Where the water went

This is where a winter break differs from a sink overflow. A pipe that split inside an outside wall, under a floor or above a ceiling sprayed or dribbled into a cavity full of insulation and wood, and gravity took it from there. Water runs along pipes, framing and wires and comes out somewhere else, sometimes a floor below.

I follow it with a moisture meter, starting where the pipe broke and working out until the readings turn normal in every direction. A thermal camera helps point to cool, damp areas, and a borescope lets me look inside a cavity through a small hole instead of tearing out a whole wall. The edge of the wet area is what sets the size of the job, so it’s worth finding on day one. More on reading the numbers is in moisture meter readings explained.

What usually stays and what usually comes out

The EPA’s water damage table for clean water is a good guide here, since a broken supply line is clean water at the start.

Sometimes opening the wall is the right answer. A foot of drywall cut out at the bottom of a wall now is cheaper than a wall full of growth in March. If the house was built before 1978 and the work disturbs painted surfaces, the EPA’s lead-safe rules apply to contractors, some of them even during the emergency and all of them once it’s over, so ask about it. Mold behind drywall covers what it looks like when drying didn’t happen in time.

Drying it, and knowing it’s dry

Air movement across the wet surfaces, a dehumidifier pulling that water out of the air, and enough heat to keep the drying going. Bigger breaks need more equipment and a plan, which is in drying out a house after water damage. Don’t close anything up, paint or reinstall baseboard until the framing reads dry. A surface that feels dry can sit over a bottom plate that’s still wet.

The Gettysburg side of a winter break

NOAA’s 1991 to 2020 normals for the Eisenhower National Historic Site station put January’s average low at about 21°F and February’s at about 22°F. That’s cold enough to freeze an exposed pipe on any long cold night. In the borough, the Census Bureau’s latest estimates put the median home’s construction year at 1942, with about 87% of homes built before 1980. Older houses have had plumbing rerouted and walls closed up over the years, so a pipe can end up somewhere cold that nobody planned.

Vacant homes are the other worry. The same Census estimates count about 12.6% of borough homes as vacant at any one time, including about 3.6% held for seasonal use. A break in an empty house can run for days. If you own one, keep the heat on, have someone check it, or shut the water off and drain the lines. The Gettysburg housing data page has the full numbers, and the borough versus township page explains why your address matters.

One thing most people don’t know

Find out where the pipe froze, not just where it broke. Ice can split a pipe a few feet from the cold spot that froze it. Fix only the split, and the same cold spot freezes the new piece next winter. The Pennsylvania Emergency Management Agency’s tips help in the meantime: open sink cabinets on outside walls, let cold water drip in a hard freeze and keep the thermostat at 55 degrees or warmer.

This is John Calhoun at Mold Remediation Gettysburg PA. If a pipe let go and you’re not sure how far the water went, I’ll bring the meter and show you the readings. The list of mold services and the overview of mold remediation in Gettysburg, PA cover the rest.