What to Do When a Pipe Bursts

By the San Marcos Emergency Plumber team · Updated September 2026

Stop the Water Before Anything Else

A burst line does not pause while you look for a bucket. The single most useful thing you can do is close the main water valve, and the time to learn where it is was last month. On most houses in this area it sits in a rectangular meter box in the grass near the curb, under a plastic or metal lid. Inside is a valve you turn to shut off the whole property. Some houses also have a shutoff where the supply enters the building, often near a hose bib. If you are on a private well, there is no meter box: you shut off the valve at the pressure tank or cut power to the pump at the breaker panel.

Once the main is closed, open a bathtub spout or an outside faucet at the lowest point you can reach. That drains the standing water out of the pipes and stops it feeding the break. Both of those steps take under two minutes and they are the difference between drying out one room and replacing a ceiling.

Protect People First, Property Second

Water and electricity share more of a house than people expect. Do not walk through standing water that is near outlets, a washing machine, a water heater or any wiring, and do not reach into a cabinet where water is pooling around an appliance. If water is running through a light fitting or into a breaker panel, stay out of the room and shut the power off at the panel only if you can reach it from a dry position. If you cannot, wait.

A ceiling holding water sags and then lets go all at once. Keep everyone out from under a bulging patch. Do not poke a hole in it to relieve the pressure unless you are prepared for everything above it to come down.

What Is Worth Doing While You Wait

Move furniture, rugs and anything with electronics out of the wet area. Lift curtains and bedding off the floor. Put towels at doorways to keep water out of rooms that are still dry, and open interior doors so air moves. Take photographs before you start mopping — they are useful later and they cost nothing now.

Write down what happened and when. Whether the pressure dropped first, whether you heard anything, whether the water was hot or cold. A hot-side failure and a cold-side failure send a technician to different places, and a line that split during a freeze looks different from one that failed at a fitting.

What to Leave Alone

Do not cut into walls or ceilings to chase the water. A leak travels along joists and top plates, so the wet patch is often nowhere near the break, and opening the wrong wall costs you twice. Do not attempt a repair with tape or a compression patch on a pressurized line. Do not run the water heater once the supply is off — an electric element without water in the tank fails quickly, so switch the heater off at the breaker or set a gas unit to its pilot or vacation setting if you can do so safely.

Why Pipes Burst Around San Marcos

Two causes dominate here. The first is freezing. Homes across Hays County run water line through unheated attics, through exterior walls and out to hose bibs with no insulation, and the February 2021 freeze showed exactly how many of them there are. Water expands as it turns to ice, the pipe splits, and nothing happens until the thaw arrives and the water starts moving again. The second is age and pressure: older galvanized supply pipe corrodes from the inside and finally opens up at a pinhole, and copper under or near a slab on clay soil takes a beating from ground that swells and shrinks with the seasons.

Newer construction is not immune. Out in the fast-growing subdivisions the supply lines are PEX, which survives a freeze far better than copper, but the fittings, the exposed garage runs and the hose bibs still fail. Plumbing service in Kyle deals with that pattern regularly.

Arrange an Inspection

Once the water is off and the area is safe, the job is to find the actual break and repair it properly. San Marcos Emergency Plumber handles burst pipe repair across the area, and if the source is not obvious the visit starts with leak detection so only the right wall gets opened. If the failure was under the floor, slab leak repair covers what that involves. Call as soon as the water is off, or check how to request a visit. Ask for the scope and the price in writing before the work starts.