Leak detection cost
A plumber charges about $240 to $290 to find a basic plumbing leak, and $300 to $750 for hidden leaks under a slab or inside walls. Finding the exact spot first keeps the repair, and the damage to walls and floors, as small as possible.
Quick answer
$300 – $750slab or hidden leak
Basic leak detection costs about $240 to $290 per leak. Locating hidden leaks under a slab or behind finished walls with electronic equipment typically costs $300 to $750. Repairs are extra.
Leak detection prices
Basic detection includes the plumber's visit, equipment and setup under normal conditions. It does not include opening walls, repairs or permits.
| Service | Typical cost |
|---|---|
| Basic plumbing leak detection (per leak) | $240 – $290 |
| Slab or foundation leak detection | $300 – $750 |
| Sewer camera inspection | $125 – $500 |
How plumbers find hidden leaks
- Acoustic listening picks up the sound of water escaping under pressure.
- Thermal imaging spots temperature differences from hot water leaks.
- Pressure testing isolates which line is losing pressure.
- Camera inspection is used for drain and sewer lines.
- Moisture meters confirm wet areas in walls and floors.
What plumbers charge for this job
Most of the price of a plumbing job is labor. Licensed plumbers in the U.S. typically charge $45 to $150 per hour, and many add a $50 to $200 service call fee that often covers the first hour. Expect evening, weekend and holiday visits to cost noticeably more; emergency hourly rates commonly run $150 to $350. Master plumbers and plumbers in high-cost metro areas sit at the top of these ranges.
Before work starts, ask whether the quote is a flat price for the whole job or an hourly estimate, and whether parts, permits and haul-away are included. See Plumber rates per hour and Emergency plumber cost for the full breakdown.
How to check for a leak yourself
- Turn off every faucet, appliance and irrigation system.
- Read the water meter and note the leak indicator.
- Wait 15 to 30 minutes without using water.
- If the reading changes, there is a leak. Close the main valve and check again; if the meter stops, the leak is inside the house.
- Add food coloring to the toilet tank. Color in the bowl after 15 minutes means a leaking flapper.
How to save
- Do the meter test first to confirm there is a leak.
- Fix running toilets and drips promptly; the EPA estimates household leaks waste nearly 10,000 gallons a year in an average home.
- Choose a plumber who offers detection and repair together.
- Ask if detection is credited toward the repair.
Frequently asked questions
How do plumbers find leaks underground?
They use acoustic listening equipment, pressure testing and sometimes thermal imaging to pinpoint the leak before digging.
Is leak detection covered by insurance?
Some policies cover the cost of finding and accessing a leak when it causes covered damage. Check your policy.
Sources
Prices are national estimates for 2026 based on published cost surveys and labor data. Your local price can be higher or lower. FairFix Costs is not a plumbing contractor; read our disclaimer.