A woman calls and says the hallway floor is warm in one spot and she thinks the slab is leaking. That is the entire report. She does not know where her main shutoff is, she has not looked at the meter, and her neighbor has already told her what it costs to jackhammer a foundation. You have about a minute before she decides whether you are the company she calls back.
This is the script for that call. It is written for whoever is holding the phone at a plumbing company, not for the homeowner, because the homeowner's job on this call is to answer questions and the desk's job is to turn a vague symptom into a dispatch decision that a tech can act on.
Assume the caller is wrong about the diagnosis
Almost every caller who says "slab leak" got the phrase from a neighbor, a search result, or a previous plumber who mentioned it years ago. Sometimes they are right. Often they have a water heater weeping at the tank seam, an irrigation zone valve that will not fully close, or a toilet flapper passing water silently into the bowl at two in the morning.
Do not correct them on the phone. Arguing about the diagnosis before anyone has looked at the meter costs you the call and gains you nothing. Take the word "slab leak" as a description of how worried they are, then work through the questions that separate the real thing from the three cheaper things it usually turns out to be.
The question order that actually works
Order matters here because the first two questions decide whether this is an emergency, and everything after that is detail you can collect while the tech is already being assigned.
Start with water on the floor. Is there standing water anywhere in the house right now, and is it spreading? Then ask whether they can hear water running when every fixture and appliance in the house is off. Stand there quietly with them for fifteen seconds if you have to. That sound, with nothing running, is the single most reliable phone symptom of a pressurized line leaking under the slab.
After that, in this order:
- Where is the warm or damp spot, and is it warm or just damp? Warm points at the hot side, which narrows the search area considerably for the tech.
- When did they first notice it, and has it changed since?
- Has the water bill jumped, and by roughly how much compared to a normal month? Take their answer as a rough signal, not a measurement.
- Is the water heater running more than usual, or cycling constantly? A hot side slab leak keeps the burner or element working all day.
- Age of the house and whether they know if it is copper under the slab or a manifold system.
- Have they had a leak repaired at this address before, and did anyone reroute lines overhead?
- Is there a deadline attached: an insurance adjuster, a home sale, a tenant.
That last one changes how you schedule, so ask it even when it feels like it is none of your business.
The meter test, which the caller can run while you are on the phone
This is the most useful two minutes on the call. Have them turn off every fixture and appliance that uses water, including the ice maker, then look at the meter. Most meters have a small triangle or a dial that spins on any flow at all. If it is moving with everything off, water is leaving the system somewhere.
Now have them close the main shutoff on the house side of the meter and look again. If the indicator keeps moving with the house valve closed, the leak is between the meter and the house, which is a service line problem rather than something under the slab. If it stops, the leak is inside the building envelope. That one step routes the truck to the right work before anyone digs.
If they have irrigation, ask them to isolate the irrigation valve and repeat the check. Sprinkler leaks look exactly like slab leaks on a water bill and cost a fraction to fix.
When to tell them to shut the main off
Tell them to close the main immediately if water is coming up through the floor, if it is standing anywhere near an outlet or a furnace, or if they are leaving the house and cannot be there to watch it.
For a suspected hot side leak with no standing water, there is a better instruction. Have them close the cold water inlet valve on top of the water heater instead of the main. That isolates the hot side and stops the loss while leaving them cold water at every tap, which matters a lot if you cannot get a tech there until tomorrow. If they close that valve, remind them to shut the gas control to pilot or kill the breaker on an electric unit so the heater is not firing against a static tank.
Write down whether they actually did it. A caller who says "I think I turned something" has not turned anything, and your tech needs to know what state the house is in when he pulls up.
Hear it handled live. Answara's own AI receptionist answers our main line. Call (857) ANSWARA and ask it whatever a customer would ask you, or see plans and get set up.
A real call, roughly as it goes
Caller: I have a slab leak. My floor is hot in the hallway.
Desk: Okay. Any water standing on the floor anywhere right now?
Caller: No, it is dry. Just warm.
Desk: Good, that buys us a little time. Can you turn off everything that uses water, then stand still and listen for a second? Tell me if you hear anything running.
Caller: ...yes. There is a hiss. It is coming from under the hallway.
Desk: That is consistent with what you are describing. Do you know where your water meter is, out by the street?
Caller: In a box by the sidewalk.
Desk: If you can get the lid up, look for a small triangle on the face and tell me if it is spinning.
Caller: It is spinning.
Desk: Then you are losing water somewhere. Here is what I want you to do before I get a tech out. On top of your water heater there is a valve on the cold pipe going in. Close that, and turn the gas dial down to pilot. That will stop the hot side from bleeding overnight and you will still have cold water at the sinks. I have you down for tomorrow between eight and ten, and the first thing the tech does is locate the leak with listening equipment. That location work is billed separately from the repair, and I will explain why in a second.
That call took under four minutes and produced a dispatch, a mitigation step, and an expectation about billing that will not come as a surprise at the door.
Explaining that locating the leak is its own step
This is where calls go wrong. The caller wants a price for "fixing the slab leak," and there is no honest price to give, because the repair depends entirely on where the leak turns out to be and what is on top of it.
Say it plainly. Finding the leak comes first, and it is separate work with its own charge. The tech isolates sections of the system, puts the line under pressure, and uses acoustic listening gear over the slab, sometimes with tracer gas or thermal imaging to narrow it down. Only once there is an X on the floor can anyone quote the repair, and the options at that point usually run from opening the slab at one spot, to rerouting that single line through the attic or a wall, to repiping the house if the same line has failed more than once.
Callers accept this readily when they hear it on the phone. They accept it badly when they hear it from a tech standing in their hallway with a jackhammer in the truck.
Dispatch priority
Same day, ahead of other work: standing water on finished flooring, water near electrical or an air handler, a single bathroom home with the main closed, an elderly or disabled occupant, or a caller who cannot locate or operate their shutoff.
Next morning: warm floor with a confirmed running sound, no standing water, hot side isolated at the heater, caller comfortable and in the house.
Routine scheduling: high water bill with no audible sound and no warm spot. Plenty of these are toilets. Ask them to dye test the tanks before the appointment and a fair number will call back and cancel, which is a good outcome for both of you.
The after-hours version
Slab leak calls come in at nine at night more than they come in at nine in the morning, because that is when the house is quiet enough to hear the hiss. Whoever answers at that hour needs to do three things: get the standing water question answered, give the shutoff instruction, and capture the address plus a callback window that a human will honor.
A voicemail box does none of that. The caller with water spreading across a hallway is going to keep dialing until somebody picks up, and the job goes to whoever does. If your after-hours coverage is a person, give them this script and the authority to page the on-call tech when the answer to the standing water question is yes. If it is an AI answering service like Answara, the same logic applies: the intake has to ask about standing water first, deliver the water heater isolation instruction, and escalate on the emergency answers rather than taking a message.