How do I prevent water damage and flooding at home?

Everything else is damage control if you cannot stop the water. City of Phoenix Water Services says that for most houses the valve "is usually located at the front of the home, near a hose bib," that you should test it regularly, and that you should not shut water off at the meter, which "requires a special tool." Walk to it, close it, open it again, and make sure the handle moves. A stuck valve is a repair to schedule now, not during a flood. Our page on testing your main water shutoff shows how.

Triple-I advises checking "hoses leading to water heaters, dishwashers, washing machines and refrigerator icemakers" every year, replacing any with cracks or leaks immediately, and replacing "them all every five to seven years." These hoses are under pressure all day while nobody looks at them. Our guide on washing machine hoses covers braided-steel versions and the warning signs.

Triple-I also advises checking the seal and caulking around showers and tubs, and when you go on vacation, shutting off the supply to the washing machine and never leaving the house with the washer or dishwasher running.

High pressure wears out hoses, valves and fixtures. EPA WaterSense notes that "Water pressure in supply main lines can reach 100 pounds per square inch (psi) or more," that most plumbing codes require a pressure-regulating valve where pressure exceeds 80 psi, and that it recommends service pressure between 45 and 60 psi. Screw a gauge onto a hose bib to see where you are; the EPA sheet describes the same test. What your home water pressure should be covers the range and the regulator.

EPA reports that the average household's leaks "can account for more than 9,300 gallons of water wasted every year." Its quick check is to read your water meter before and after a two-hour period when no water is being used: "If the meter changes at all, you probably have a leak." Our guide to the water meter leak test walks through it. EPA also points to leak detection and flow monitoring devices, and Triple-I mentions leak monitoring and shut-off systems. If you want a sensor, the best spots are the water heater, the washing machine, under the kitchen sink and beside the toilet; see whether leak sensors are worth installing and how smart shutoff valves work.

A slab leak or a leak in a wall will not show on the surface at first. The signs and what to do are in signs of a slab leak in Arizona.

Triple-I's exterior list is short and cheap. Clear debris from downspouts and gutters, position downspouts "so that they direct water away from the house," inspect the roof, and make sure "sprinklers and irrigation systems" are not "creating water damage to the walls and foundations of the house." It also says to make sure water drains away from the building, since soil that has settled can send rainwater down the outside of a foundation wall. In Phoenix, check that irrigation heads near the house are not spraying the stucco and that the grade slopes away from the slab.

Triple-I says some policies cover sewer and drain backups, "but many do not," and that you can buy a rider. It also advises installing and maintaining a backwater valve, "which allows sewage to go out, but not come back in." If your street surcharges in storms, read how to prevent a sewer backup before monsoon and when a backwater valve is required.

Flood from the ground up is a separate insurance question. The Flood Control District of Maricopa County says flood damage "is not typically covered by homeowners' insurance policies," that "1 in 4 flood insurance claims come from outside a floodplain," and that there is "a 30-day waiting period" before coverage takes effect. Buy before the season, not when a storm is in the forecast. Whether your Arizona house is at risk of flooding during monsoon explains how to check your zone.

Phoenix freezes occasionally. The city's advice for a freeze warning includes draining and storing hoses, closing inside valves to outdoor bibs and keeping garage doors closed if supply lines run through the garage; see whether to let faucets drip during a freeze. If you travel in cold weather, the city says to set the thermostat "no lower than 55°F," and for a long absence to shut off the water to the house and to the water heater.

Shut off the main, turn off power to wet areas if it is safe, and call. What to do first after a flood or major water leak lists the sequence. HQ Plumbing and Air handles leak repair and emergency calls 24/7, and a firm price comes before work begins. See emergency plumbing or leak detection.