Your Water Heater Is Leaking — What to Do Before It Becomes a Flood

A water heater holds 40, 50, sometimes 75 gallons of water under pressure, around the clock, for years on end. Most of the time you never think about it — until you find water pooling around its base, or worse, walk into a flooded garage or closet. In Plano and across DFW, a failed water heater is one of the larger single-source floods we respond to, simply because of how much water a tank holds and where these units tend to be installed. Knowing what to do in the first few minutes makes the difference between a manageable cleanup and a soaked home.

Why water heaters leak

Not every water heater leak is the same, and the source tells you how urgent it is:

• The tank itself. This is the serious one. Over years, sediment builds inside the tank and the steel corrodes from the inside out. Eventually it rusts through, and water seeps — then pours — from the body of the tank. A leaking tank cannot be repaired. It has to be replaced, and it can fail completely with little warning.
• The temperature-and-pressure (T&P) relief valve. This safety valve discharges water if pressure or temperature climbs too high. If you see water at the discharge pipe, the valve may be doing its job — or it may be faulty. Either way it needs attention, because it points to a pressure problem or a worn valve.
• The drain valve. The valve at the bottom used for flushing the tank can loosen or fail and drip.
• Inlet and outlet connections. The fittings where the cold water comes in and the hot water goes out can corrode or loosen over time.

A drip from a valve or fitting is often a straightforward repair. Water coming from the tank body is the tank telling you it's done.

Why location makes it worse in DFW homes

Where your water heater lives determines how much damage a failure does. In our area, you'll typically find them in one of three places:

• The garage. The most forgiving spot — a slab floor and usually a drain nearby. Even so, 40-plus gallons spreads fast and can reach drywall, stored belongings, and an adjacent room.
• An interior closet. Here a failure soaks the closet, wicks into surrounding walls, and spreads into hallways and rooms. Many of these have a drain pan, but a pan only handles a slow drip — it can't keep up with a tank that lets go.
• The attic. The worst case. A tank failure in the attic sends water straight down through the ceiling into the rooms below, often across a wide area. In a two-story home, that can mean damage on multiple levels. If your heater is in the attic, the drain pan and its drain line are critical — and worth inspecting.

What to do when you find a leak

1. Shut off the water to the heater. There's a shut-off valve on the cold water line at the top of the tank — turn it clockwise until it stops. If you can't reach it or it won't turn, go to your home's main shut-off (often near the water heater, in the garage, or in a box near the foundation).
2. Turn off the power or gas. For an electric heater, switch off its breaker. For a gas heater, turn the gas control valve to "off." This is important: a heater that keeps heating after the water's off can be damaged or dangerous.
3. Drain pressure if it's a tank failure. Opening a hot water faucet somewhere in the house relieves pressure and slows the flow from the tank.
4. Protect the area. Move stored items and anything valuable out of the water's path. If the unit is in an attic and water is coming through the ceiling below, a bulging ceiling is a balloon full of water — a small relief hole at the lowest point, into a bucket, beats the whole section collapsing.
5. Document everything. Photograph the heater, the leak, the standing water, and any damaged belongings before cleanup. This supports your insurance claim.

Will insurance cover it?

Texas homeowner policies generally cover the sudden and accidental water damage a failed heater causes — the soaked drywall, flooring, and belongings. What they typically won't cover is the heater itself, since the tank wearing out is considered maintenance, not a sudden accident. Document the failure and the resulting damage, and don't delay mitigation; policies usually require reasonable steps to limit further damage once you're aware of the problem.

What you can handle, and when to call

Some water heater leaks are genuinely minor. A loose drain valve or a fitting that needs tightening may be a simple fix, and a plumber can replace a worn T&P valve. If you've caught a small drip early, addressed the source, and nothing has soaked into the structure, you may be fine after a cleanup.

The picture changes fast with volume and time. Here's the honest threshold:

• A tank that has leaked a significant amount, or failed outright? You're dealing with dozens of gallons. Even on a garage slab, that water spreads into walls and adjacent spaces, and an interior or attic failure soaks structure on contact. That's a drying job.
• Water that reached drywall, baseboards, flooring, or insulation? Those materials hold moisture long after surfaces look dry, and within 24–48 hours that trapped moisture turns mold-friendly — faster in Texas humidity. Wet insulation in particular usually has to come out.
• An attic or upstairs failure, or any water that reached the level below? Assume the damage is larger than what you can see, and get it mapped before it dries in place.

A restoration crew finds the water you can't see with moisture meters and thermal imaging, then dries the structure to a measured standard with commercial air movers and dehumidifiers — verified dry, not "feels dry." With a tank failure, fast water removal is what keeps a big single-source flood from becoming a much bigger repair.

Preventing the next failure

• Know your heater's age. If it's past 8 to 12 years, start planning to replace it before it fails on its own schedule — usually the worst possible time.
• Flush the tank annually. Draining the sediment slows the corrosion that eventually kills the tank.
• Check the T&P valve and connections periodically for drips or rust.
• Make sure there's a drain pan with a working drain line, especially for closet and attic installs. A pan won't stop a full failure, but it buys time against a slow leak.
• Consider a water sensor or auto-shutoff at the base of the heater — an early alert can mean catching a leak before it becomes a flood, particularly for an attic unit you'd otherwise never notice.

Bottom line: a water heater leak ranges from a quick fix to a multi-room flood, and the volume of water in that tank is the reason to take any leak from the body of it seriously and act fast. Shut off the water and the power or gas, protect the area, document the damage, and get hidden water dried before mold sets in. If your tank has failed or water is spreading, call Flood Dry Elite at 469-555-0140 for 24/7 emergency response across Plano and DFW, with a crew on-site in under an hour.

Frequently asked questions