Burst Pipe in Pittsburgh: Here's How to Stop the Damage Fast

A burst pipe in Pittsburgh nearly always lets go on the one cellar wall the hill is not holding up. Houses on these slopes have foundations cut into the ground on the uphill side and standing free on the downhill side, so half the cellar sits in earth that never gets near freezing and the other half sits behind a single course of masonry with wind on the far side of it. Water lines were run across the whole room without much regard for which half they were crossing. When one splits, you have a few minutes that count for more than everything you do afterward.

Key Takeaways: A Burst Pipe Here Picks the Wall the Hill Does Not Cover

• The buried side of a hillside cellar holds ground temperature all winter. The exposed side tracks the air, and that is where a split starts.
• Close the water before you look for anything. Finding the break costs minutes and every one of them is arriving through the break.
• The interior valve is usually near where the service enters, which on a slope is the far corner of the cellar from the wall that froze.
• Galvanized steel is still in service in a lot of the older housing, and it splits at the threads where the wall of the pipe is thinnest.
• Rear kitchens and back porches on these lots are carried out over the slope with open air underneath, which puts supply lines in an unheated floor.
• Repeated freeze and thaw does more damage here than a single hard night, because each cycle works the same weak joint a little further open.
• Roto-Rooter is fully licensed and insured and takes calls for a burst or leaking pipe 24/7, 365 days a year.

Stopping a Burst Pipe: What to Close, and in What Order

1. Close the main valve inside the house. It sits on the incoming line near the point the service comes through the foundation. Turn it fully and leave it closed.
2. Open a low faucet. The laundry tub or an outside spigot lets the standing water in the pipes drain to a low point instead of continuing out the split.
3. Kill power to the wet area from the panel if you can reach it dry. If the water is anywhere near the panel or a socket, do not reach past it, and get the utility or an electrician to isolate the house at the meter.
4. Get the water off anything that will not survive it. Cardboard on a cellar floor collapses within the hour, and stored furniture wicks upward faster than it looks like it should.
5. Leave the heat on. Turning the furnace down to save fuel while the house is torn about is how the next section of pipe freezes behind the first.

One Cellar Wall Is Buried in the Hill, the Other Is Not

Take a house on any of the ridges above the rivers. The back of it is dug into the slope, so the rear foundation wall has several feet of earth against it and never drops far below the temperature of that ground. The front, or whichever end faces downhill, is fully out of the ground. It has windows in it, a door out to the yard, and nothing but block or brick between the cellar air and the weather.

Plumbers running supply lines a century ago clipped them to the joists straight across the room, which means a good number of houses have a copper or galvanized run that starts in the warm buried half and finishes hard against the cold exposed wall. Ice forms at the cold end. It does not burst the pipe where it forms, either. The plug grows, pressure builds in the closed length of pipe between the plug and the nearest fixture, and the failure happens at the weakest point in that trapped section, which can be several feet back toward the warm end.

Two more things follow from that geometry. Wind matters, because an exposed masonry wall with air moving across it loses heat far faster than a sheltered one, and the hillsides get plenty of moving air off the valleys. And the damage runs downhill. A cellar floor on a slope is rarely level, so water leaves the split and heads for the low corner, which is where the stored boxes and the finished part of the room usually are.

Where the Shutoff Sits When the Street Is Above the Roofline

The standard advice is to close the main and then, if that fails, the curb valve out at the street. On level ground that is two easy steps. Here it is worth knowing in advance which of your two neighbors is the street.

Water arrives from the main under the road, so on a lot below the street the service enters high on the uphill wall and the interior valve is up under the ceiling at the back of the cellar. On a lot above the street it comes in low at the front. Either way, the valve is at the point of entry, and that is usually the opposite end of the room from the exposed wall where the split happened. Walking to it through water in the dark is not the moment to be learning the layout.

The curb valve is a second problem. It sits in the sidewalk at street level, and where a house is reached by one of the city's public stairways rather than a driveway, that can be a full flight of steps away and buried under leaf litter. It also takes a long key to operate and belongs to the water utility, not to you. Find the interior valve, label it, and make sure more than one person in the house knows where it is.

Which Runs to Check Before the Next Cold Night

Walk the exposed wall with a torch and look at what is clipped to it. Anything running along that face, crossing a cellar window well, or feeding an outside spigot through it is the priority, and pipe insulation on those few feet does more good than insulating the whole cellar. Close and drain the outside spigots at the end of the season.

Then look at the back of the house. A kitchen or bathroom added out over the slope on posts or a low pier wall has a floor with open air under it, and the supply lines in that floor are effectively outdoors. Sealing the perimeter under that addition and insulating the pipes rather than the floor is the fix that holds. Old galvanized deserves attention wherever you find it, since it is thinnest at the threads and that is where it opens up.

Frequently Asked Questions About a Burst Pipe on a Pittsburgh Hillside

The back of the cellar is dug into the hill and the front wall faces the street. Which end actually freezes?

The end out of the ground. Earth against a wall is a slow, stable heat store and it keeps that side well above freezing even in a cold week. The free-standing wall follows the air within hours, and any window or door opening in it makes that faster.

Our water service comes in at the uphill end and the break is at the other end of the cellar. Do I still shut off where it enters?

Yes. The valve at the entry point closes the whole house, wherever the break is. Individual fixture stops only isolate that fixture, and a split in a run between two fixtures is not covered by either of them.

The curb valve is out in the sidewalk at the top of the public steps. Can I close that one myself?

It is better not to. That valve belongs to the water utility, needs a long key, and sits in a small pit that fills with grit and leaves. Forcing an old curb stop can break it, which turns a repair into a utility excavation. Use the interior valve, and call the utility if it will not hold.

The rear kitchen sits out over the slope on posts. Does the floor need insulating, or the pipes?

The pipes first, and the perimeter second. Insulating the floor deck alone can make things worse by cutting the pipes off from the heated room above them while leaving them open to the air below. Wrap the lines, then close in the open perimeter so the space under that addition is not a wind tunnel.

We would rather replace the whole exposed run than patch one split. How does that get costed against a repair?

Both get looked at on the same visit. A single clean split in sound copper is a straightforward repair. A run of galvanized that has opened at one thread is usually thin at the others, so replacing the length is the option that stops you doing this again next winter. Cost varies with the material, the length and how much has to be opened up to reach it, and Roto-Rooter provides on-site estimates before any work begins, so both routes are priced before you decide.

Call Roto-Rooter, Then Leave the Water Off Until Someone Looks

Reopening the valve to see whether it is still leaking is how a small repair becomes a wet ceiling. Roto-Rooter has been fixing this since 1935, works across the city and the surrounding boroughs, and can trace the run rather than guessing at the wall. You can schedule online, reach the overnight team through Pittsburgh emergency plumbing, or start at the Pittsburgh plumbers page.