Leak detection and pipe repair in Seattle: find it, fix it, document it

How can you tell if you have a hidden leak?

Seattle Public Utilities calls leaks a common cause of higher than expected water bills and says your water meter may be your most useful tool. Its test takes about half an hour:

1. Find your water meter. In Seattle it is usually in the parking strip or sidewalk at the front or side of the house. If you cannot read it yourself, SPU Utility Services can help.
2. Find the building's shutoff valve. It can be indoors or outdoors, and some buildings have more than one. SPU advises having a plumber install one if you do not have a shutoff.
3. Turn off all faucets and water-using appliances.
4. Note the position of the 1 cubic foot dial on the meter, wait 30 minutes and read it again. The readings should match.
5. If the dial moved, close the building's shutoff. If the dial stops, the leak is inside the building; check running toilets and faucets first. If it keeps moving with the shutoff closed, the leak is underground, between the meter and the shutoff.

Other signs worth investigating: damp spots, stains or warped flooring, the sound of running water when everything is off, mold or a musty smell in one area, and, according to HomeAdvisor, staining and sagging along the foundation.

What does leak detection cost?

No official source publishes Seattle leak detection prices, so these are national ranges from HomeAdvisor's 2026 guides.

HomeAdvisor says labor makes up nearly 80 percent of a burst pipe repair bill, and that an emergency call-out fee may add $100 to $300. Water damage repair is extra.

How do professionals find a leak?

A leak specialist usually starts with the same meter logic SPU describes: isolate parts of the system with valves to see where water is being lost, then narrow the location before opening anything. The goal is to open the smallest possible section of wall, floor or yard. HomeAdvisor notes that slab leak costs depend on detection fees, pipe type, the access method and the severity of damage. Ask the contractor which methods they will use and whether the detection fee is credited if they also do the repair.

Leaks in the line between the meter and the house are usually the owner's responsibility to repair. SPU's leak adjustment rules, below, treat these underground leaks separately, with an inspection before the trench is closed.

Can SPU reduce your bill after a leak?

SPU offers billing adjustments for most types of leaks, with conditions:

• The repair must be completed within sixty days after you receive the initial high bill that showed the leak.
• For an underground leak between the meter and the house, an inspection is required. Contact SPU Utility Account Services once repairs are complete to schedule it, and do not backfill or cover any repair until SPU has inspected and approved it.
• For other leaks, SPU asks for proof of repair, such as photographs, receipts or invoices, or a written explanation.
• Adjustments do not cover high use caused by theft, vandalism or negligence.

Tell your contractor about the SPU inspection before work starts, so the trench stays open until it is approved.

What permits and licenses apply?

Repairing an existing pipe inside the house is plumbing work, which L&I says requires a certified plumber when someone else does it for pay. Rerouting or replacing water lines changes the plumbing system, and Public Health Seattle and King County says codes require a permit to install, relocate or change a plumbing system. Check the company in the L&I verify tool before work starts and ask who applies for the permit.

If water is actively spreading, close the main shutoff first; our emergency checklist covers what to do and whom to call. Older homes with galvanized steel or other aging pipe can develop repeat leaks; see old house plumbing in Seattle.

We are an independent guide and do not do this work. You can send a request through our contact page; we reply with next steps and, where we know a licensed contractor for your area, an introduction.