Is a slab leak an emergency?
Usually not a same-night emergency, and never something to leave for a month. A slab leak is water escaping continuously under your foundation, so the damage accumulates rather than arrives. The exception is water actually surfacing inside the house (wet flooring, a soaked carpet, a warm wet patch) which is an urgent call. A jumped water bill with no visible water is a this-week problem, not a tonight problem.
Which one do you’ve
- Water visible inside the house: wet flooring, damp carpet with no source above it, a warm wet patch of tile. Treat as urgent. Shut the main and call.
- Warm floor spot, no visible water: likely a hot-line slab leak. Days, not hours. Get it located this week.
- Water bill jumped, nothing visible. The most common presentation. Not urgent tonight. Genuinely urgent this month, because you’re paying for it continuously and some insurance policies exclude leaks characterized as gradual.
- You can hear water running with everything off: same category. Confirm it with the meter test below and book it.
The free test, tonight
Shut off every fixture in the house. Note the reading on your water meter at the curb. Wait an hour without using anything. If the meter moved, water is going somewhere it shouldn’t. That costs nothing, takes an hour of not using water, and turns a suspicion into a fact you can hand a plumber.
A follow-on that narrows it further: shut the main valve where the supply enters the house and watch the meter again. If it still moves, the leak is upstream of the house. That’s the service line in the yard, not a slab leak. Two different jobs, two very different quotes.
Why waiting is the expensive choice even when it’s not an emergency
The leak itself doesn’t get much worse quickly. What gets worse is everything around it: continuous water under a slab, a bill you’re paying every day, and an insurance conversation that turns on how long it went on. Many policies treat sudden resulting damage differently from a gradual leak, and some exclude gradual entirely. Acting on a jumped bill is partly a plumbing decision and partly a claims decision.
What not to do at 11pm
Don’t pay an after-hours premium to have someone come and tell you what you already suspect. Unless water is actively coming up into your living space, the honest advice is: run the meter test tonight, photograph anything wet, and book a leak detection for business hours. Detection is a daylight job done with listening equipment, and it’s done better unhurried.
Where this page cites a utility, permit or housing figure for a specific town, it’s that town’s published data. Your own city’s water report applies to your tap and your city’s building department sets your permit rules; ask us which apply to your address.
The next thing you were going to ask.
A leak in the lines under your foundation. In the slab-on-grade East Valley, it's the expensive one.
How much does a plumber cost in the East Valley, AZ?→Service call fees, hourly vs flat-rate, and why the second number is usually the real one.
How do I know if a plumber is overcharging me?→You can't, mid-emergency, without a range in your head first. That's the whole trick.