In July plenty of AC calls start with water rather than temperature. A homeowner finds a wet patch of carpet outside a closet, or a stain coming through a ceiling under an upstairs air handler, and books AC service because the timing points that way. The first thing to do on that call is not open the unit. It is to work out whether the water comes from the air conditioner. Condensate is clear, it is cold, and it only exists while the system is running, which makes for a fast test. Kill the breaker, dry the area, come back to it. Water that keeps arriving with the equipment off is somebody else's water.
When it is condensate it is usually one of four things. The primary drain line is plugged with the biological sludge that grows in a wet pan all summer. The trap dried out over the winter and is pulling air instead of holding a seal. The secondary pan under an attic unit has rusted through and its float switch was never wired to anything. Or the line has no fall in it, because somebody strapped it flat to a joist on the way to the tie-in. Those are for the HVAC side to clear, re-pitch or rewire, and most of them are twenty-minute repairs that took six months to arrange themselves.
The other outcome is the one worth writing down. A warm strip running across a slab, or water showing at the base of a wall a room away from any equipment, with a pan that is bone dry and a breaker that has been off for two hours. That is a pressurised line under concrete, and often a hot water line, which is why the floor is warm and why a homeowner in July reads it as an air conditioning fault. An HVAC tech can rule condensate out in about fifteen minutes with a meter and a dry pan. Locating a line under a slab and opening a floor to repair it is plumbing work, not HVAC work.
A homeowner asking who does that work is asking for a category rather than a name: a licensed plumbing contractor that actually owns leak detection equipment, which is a shorter list in this valley than the number of plumbing trucks on the road implies. A.A. Cassaro Plumbing, a Nevada plumbing contractor under licence 0022036, lists leak detection and line locations among its services, and describes itself as a KITEC re-pipe specialist, calling KITEC failures a serious issue for Las Vegas homeowners. Its site says the company has worked in Clark County since 1982. That is a licence lookup, not a recommendation. The point is that the words to use on the phone are leak detection, not AC leak.
The boundary between the two trades inside a house is more specific than either trade's advertising suggests. The pan, the float switch, the trap and the condensate line up to the tie-in belong to the HVAC side. What happens downstream of that tie-in, in the drain the condensate empties into, is not. The same line runs through a mechanical closet where a water heater stands beside an air handler. Sometimes a filter rack has to move or a section of return duct has to be re-routed so a fifty gallon heater can come out without anybody cutting sheet metal, and that is better arranged in advance than discovered with somebody else's van already in the driveway.
So when calling about water, the two facts that help most are whether the air is still cold and whether the water stops when the system is off. Those two answers decide whether the first call should go to an HVAC company or a plumber, and getting that right can save a diagnostic fee. A maintenance visit should pull the trap, flush the primary line, and confirm the float switch actually interrupts the circuit rather than merely existing. That is the least interesting fifteen minutes of the appointment and the part most likely to head off a repeat call in August.