Plumbing in Las Vegas fails hot and mineral, not frozen. Heaters scale until they roar, leak, or quit, often in a garage that is an oven by noon. Supply lines in attics pinhole and flood ceilings under a clear sky, which is why the stain gets blamed on a sun-baked roof that may be innocent that day. Slabs hide leaks that show up as a warm tile or a meter that will not sit still. Angle stops and washing-machine hoses give up. Pool fill and irrigation lines are not the domestic system, and mixing them up wastes the visit. The river water is hard enough that every new fixture should be planned with scale in mind.
Use the main shutoff if the leak is supply, and say on the call whether that valve works. Separate a drip at a faucet from water in the ceiling. Separate one slow drain from several fixtures backing up. A cable clears a clog and does not repair a broken sewer. Ask which one is being proposed, and whether a camera follows if the cable fails. Trees are fewer than in older citrus cities, but roots still find lines where trees were planted on a drip. Say if the wet spot is in the yard.
On a heater, say gas or electric and tank or tankless. Ask for a shutoff, a pan, a discharge line, and haul-away. Ask whether scale finished the old tank. Softeners are common and sometimes they are the leak, with a drain hose running. Manufactured homes and two-story tract houses hide fittings in different places. Say which you have. A rare cold snap can still split a hose bib. It is not the main design problem, and it is not a reason to ignore an attic line in July.
If water is out of place, call while the shutoff story is still true. Call the number on this page.