A broken main line is the burst pipe homeowners notice last and cringe at first. It’s buried, it carries the full supply to the house, and fixing it usually means digging. Before getting into the repair, it helps to know which part of the line is yours.
Who is responsible for which part?
WSSC Water maintains the water main under the street and the connection up to your property line. The service line from the property line to your house, and all the plumbing inside, belongs to the homeowner. WSSC’s emergency center is at 301-206-4002. Call it if you see water bubbling in the street, or if you’re not sure which side the leak is on. If the leak is on your side, WSSC can confirm this, and you’ll need a plumber.
That’s separate from the pipes inside the building, which our page on emergency burst pipe repair covers.
Signs the main line is leaking or failing
- A sudden drop in water pressure throughout the house, not just at one tap.
- A wet, soft or unusually green patch of lawn, or water pooling in the yard without rain.
- A water bill that jumps with no change in how you use water.
- A meter that keeps turning when every fixture is off. Check it after you’ve closed everything.
- Dirty or discolored water, or the sound of running water when nothing is on.
- Cracks in a foundation, driveway or slab that are damp.
Not sure whether the leak is underground? The meter test on our Fallsmead page takes about five minutes. And if your property uses a private well and not WSSC water, the Fawcett Farms page explains what changes.
What repair involves
- Locate the leak. A plumber may use listening equipment or trace the line to pinpoint the break before digging.
- Call 811 before any digging. Maryland law requires a locate request before excavation so buried gas, electric and other utilities are marked. Plumbers who dig regularly know this, but it’s a fair thing to ask.
- Excavate and repair or replace. A short break can be cut out and repaired. A line that is old, corroded or damaged in several places is often replaced end to end.
- Test and restore. The line is pressure-tested, the trench backfilled, and surfaces restored as agreed.
Some projects can be done with less digging, using trenchless methods. Whether that fits depends on the line and the site, and it’s a question to put to the plumber.
Permits and licensing. WSSC’s plumbing code requires a WSSC-licensed plumber for water service line repairs and replacements in its service area, which includes Montgomery County. Permits are normally part of the plumber’s job. When you call around, ask: are you licensed with WSSC, and will you pull the permit?
Long driveways, big lots, longer lines
The farther the house sits from the street, the longer the service line, and the more of it there is to fail and to dig. That is one reason main line problems matter on larger properties, which you’ll find in parts of Glen Hills and Great Falls Estates. Where a driveway, patio or mature tree sits over the line, ask the plumber how restoration will be handled and who pays for it.
Cost factors
Price depends on the length of line, how deep and where it runs (under lawn is easier than under a driveway), the pipe material, whether the repair is a section or the whole line, and surface restoration. Ask for a written estimate that spells out what’s included. A burst main on a weekend or overnight will often cost more than the same job during the week.
Repair or replace the whole line?
If the break is a one-off, such as damage from digging, a repair may be all you need. If the line is galvanized steel, lead, or older poly material that has been failing, replacing it can end a cycle of repeat digs. The plumber can describe the condition after inspecting the line. If the rest of the house plumbing is also showing its age, read our page on pipe replacement and repiping. People weighing everything up usually start from the general picture of emergency pipe repair in Potomac, MD and then narrow down to the line itself.
Questions people ask
How do I know if the leak is on my side or WSSC’s side?
Can I shut off the water to my house if the main line is leaking?
Will my homeowners insurance cover a broken water line?
Does a main line repair require a permit?
Related services
Emergency Burst Pipe Repair
A split pipe or blown joint with water actively escaping.
Frozen Pipe Repair
Thawing frozen lines and fixing the splits ice leaves behind.
Pipe Replacement / Repiping
Replacing worn-out or failing pipe, in part or the whole house.
Commercial Burst Pipe Repair
Offices, retail units and multi-tenant buildings with a burst line.
A note on this guide. This page is general information, last reviewed October 2026. It can’t replace a plumber looking at your actual pipes, and Burst Pipe Fix Pros does not perform plumbing work.