Call and describe the problem
Say what you can see and hear, which fixtures are affected and whether water is still running. That helps check whether an independent plumber is available; timing depends on the provider and location.
There is nothing complicated about it. You call, you are connected with an independent plumber if one is available, the provider finds the cause and gives a price, and work happens only once you say yes. Here is the same thing with the detail filled in, so nothing on the day comes as a surprise.
Say what you can see and hear, which fixtures are affected and whether water is still running. That helps check whether an independent plumber is available; timing depends on the provider and location.
If it is safe, close the fixture valve, the main valve where the line enters the house, or the valve in the meter box at the street. Nothing you have to force, and nothing near live power.
Ask the independent plumber to find the actual cause rather than the nearest symptom, explain what the repair involves and give you the price. Where more than one sensible option exists, ask about each.
Work should start only once you approve it. Afterwards, ask the provider to test the repair under pressure or by running the fixtures, and to show you what was replaced and where your shutoff valves are.
If water is escaping, stopping it comes first. In most Tucson-area homes the main shutoff is on the supply line where it enters the house at the front, often beside a hose bib, and many houses have a second valve in the garage at the softener loop. There is also a valve in the meter box near the street, which usually needs a meter key. Find yours on a calm afternoon and check that it actually turns, because a seized valve at two in the morning is a second problem on top of the first.
Stay off wet flooring near outlets, appliances and ceiling fixtures, and do not open a ceiling that is bulging with water. If a water heater is leaking, switching off its breaker or turning its gas control to off is worth doing only when the control is dry and easy to reach. Anything involving a gas line, a pressurized pipe or sewage is worth waiting for rather than attempting.
Read about the services described here, check your area on the service areas page, look through common questions, or weigh the options on our water heater repair or replacement guide.
What failed, why it failed and what happens if it is left alone. If a camera or a pressure test was used, you get to see the result for yourself.
Where repair and replacement are both reasonable, you hear both with the trade-offs. Nobody should be steered toward the bigger job by default.
Approve the scope and the price before any pipe is cut. If something unexpected turns up behind a wall, ask the provider to stop and confirm with you again.
Call to check whether an independent plumber is available for your property.