Water leak detection cost

Leak detection costs $150 to $800, typically around $350. It is the step people skip and the one that decides whether the repair costs $600 or $6,000, because a leak found precisely is a small hole in one wall and a leak guessed at is three.

Some plumbers waive or credit the detection fee if you have them do the repair. Ask before booking.

What it costs

A company that quotes $99 for detection is usually quoting the visit and pricing the equipment separately once they arrive.

The test you can run yourself first

It costs nothing and it answers the only question that matters: is there a leak at all.

1. Turn off every faucet, appliance and ice maker in the house.
2. Find the water meter and note the reading, or watch the small triangular or dial-shaped leak indicator.
3. Wait two hours without using any water.
4. Read it again.

Any movement means water is leaving the system. If the leak indicator spins with everything off, the leak is significant.

To narrow it further, shut the main valve into the house and repeat. If the meter still moves, the leak is between the meter and the house, which is the buried service line. If it stops, the leak is inside.

What the symptoms usually mean

A warm patch on a floor is a hot water slab leak. This is the classic sign and it is worth acting on quickly, because hot water erodes concrete and soil faster than cold.

A bill that jumped with no change in use. A running toilet flapper wastes more water than most people believe, and it is the first thing to rule out: put food coloring in the cistern, wait twenty minutes without flushing, and look in the bowl.

A stain that comes back after painting. Water is still arriving. Paint is not a diagnosis.

The sound of water running with everything off. Stand at the meter with the house silent. This is how most slab leaks are first noticed.

Mold or a musty smell in one place. Something has been wet for weeks.

Cracks in a slab or a patio, or a soggy patch of lawn in dry weather. Buried line.

What a proper detection visit produces

Not a guess. It should give you:

• A marked location on the floor or wall, with a rough depth
• Which line it is: hot, cold, supply, drain
• A photograph or a thermal image
• A repair quote for that specific location, and the alternative if it is wrong

If a company tells you the leak is "somewhere under the kitchen" and quotes to break up the slab, that is not detection. Pay someone else.

Frequently asked questions

Is leak detection worth it, or should I just have them open the wall?

Worth it in almost every case where the leak is not visible. Detection is $350; a wrong wall is $500 in drywall and paint and you still have the leak. It only stops making sense when the pipe is fully accessible and you can see the drip.

Do plumbers charge for detection if I use them for the repair?

Many credit it, some waive it, some do not. It is worth asking directly, and worth asking before you agree to the visit rather than after.

Can a plumbing leak be found without breaking anything?

Usually. Acoustic equipment hears pressurized water escaping through concrete and tile, and tracer gas finds what sound cannot. Neither is perfect on a slow drain-side leak, which is not pressurized and is genuinely harder.

My meter moves but I cannot find anything.

Common causes are an irrigation zone valve leaking underground, a leaking toilet flapper, a water softener stuck in regeneration, and a leaking outside faucet. Shut the irrigation supply separately and repeat the test.

Will insurance pay for the detection?

Many policies cover the cost of accessing and locating a covered leak, including breaking into the slab or wall, even when the pipe itself is excluded. Ring and ask before you spend, because the answer varies more than most parts of a policy.