Water damage, by source
A pipe can fail in plain sight under a sink or out of sight inside a concrete slab. Both put clean water into the house, but they are found, repaired and dried in different ways.
A burst supply line can put out a great deal of water in the time it takes to find the shutoff, so learn where the main valve is before you need it. It is usually close to where the service line enters the house, often near a front hose bib or in the garage. Close it, then open a faucet at the lowest point of the house to relieve pressure. If the leak is on the hot side, turning off the water heater's gas or breaker protects the tank once it stops refilling.
When nothing is visibly spraying but the floor feels damp or the water bill jumped, the meter helps. Turn off every fixture, irrigation and the ice maker, then watch the meter's leak indicator for a while. Movement with everything off means water is going somewhere. Other common signs of a hidden line are a warm patch on a tile floor, the sound of running water when the house is quiet, and baseboards swelling along one wall.
Where a house sits on a slab, supply lines often run under or within the concrete. Scottsdale's historic-preservation survey describes its 1960s and early 1970s townhouses as slab-on-grade with no basement, and Tempe's postwar Borden Homes were built on slab foundations too. A leak under a slab has nowhere to drain, so it pushes up through the weakest point: grout lines, the seam where tile meets carpet, or the bottom of an interior wall. Leak detection uses pressure tests and acoustic equipment to place the break before any concrete is cut.
Repair is a plumber's decision. A single break can be reached by opening the floor above it, while repeated failures in the same system often lead to rerouting lines through walls or the attic instead. Either way, the water already released stays in the slab, flooring and wall bottoms after the line is fixed. That is where restoration starts: readings across the slab, removal of flooring that trapped water, and dehumidification set up for concrete, which gives up moisture slowly.
Phoenix's own service-line FAQ notes the 1986 federal lead-solder ban and an ongoing inventory of lead, galvanized and unknown service lines.
Many leaks are not in the pipes at all but in the short connectors to toilets, faucets and appliances. Braided supply hoses and plastic compression fittings age, and a failure often happens when no one is home. Hard water adds to the wear: the City of Phoenix's 2025 water-quality report puts distribution-system hardness at 10 to 17.6 grains per gallon and says hard water can cause scaling in pipes and water heaters. Replacing older connectors with new ones is simple work an owner can often do with the fixture valve closed.
Plumbing age follows house age. The census puts Phoenix's median year built at 1985, with 41.6% of housing units built before 1980, and Phoenix notes the 1986 federal ban on lead solder in plumbing. Cities are now inventorying service-line materials: Mesa's inventory focuses on buildings from before 1989 and sorts lines into lead, galvanized, copper, plastic or unknown, and Phoenix replaces lead or galvanized lines it finds during maintenance. In an older house with original lines, one leak can be a sign that others may follow, so a plumber may suggest checking the rest of the system.
The sequence matters for both the house and the claim. A plumber stops and repairs the leak, and the invoice should describe the cause, location and pipe material. Restoration follows with extraction of standing water, removal of soaked flooring or drywall where needed, then drying with daily readings until materials meet a dry standard. Water from a burst supply line is usually Category 1, which means more materials can be dried in place if work starts promptly.
Insurers often separate a sudden break from a slow leak that went on for weeks, and the repair of the pipe itself may be handled differently from the water damage it caused. Photos of the break, the plumber's notes and the moisture map are what an adjuster usually needs; the claims page goes through the rest. Where a leak wet a ceiling below, see wet ceilings and drywall.
Pipes can also break as part of storm damage. In August 2021, a north Phoenix church had a roof collapse during a storm, its main sprinkler pipe broke, and about 4 inches of water spread across a building of roughly 30,000 square feet. When a pipe failure and rain arrive together, the plumber, the roofer and the restoration crew should each document their part, because an insurer may handle the two causes under different terms.
Often the resulting water damage from a sudden break is covered, while gradual leaks and wear are commonly excluded. Repair of the pipe itself may be treated separately. Policies differ, so read yours and report the loss promptly with photos and the plumber's invoice.
Common signs are a warm spot on the floor, the sound of running water with every fixture off, a water meter that keeps moving, and damp or swelling baseboards. A plumber's leak detection confirms the location before any concrete is opened.
If the main water supply is shut off, turning off the water heater's gas or power is a sensible precaution, because a tank that cannot refill should not keep heating. Turn it back on only after water service is restored.