Free calculator
Water Heater Leak Calculator
Estimate how much water a leaking or failed water heater has released.
Estimates use typical industry ranges and published methods. They are not a quote. An on-site moisture inspection sets the actual scope.
Shut it down in this order
- Turn off the cold water supply — the valve on the pipe entering the top of the tank. If it won't turn, close the main shutoff.
- Turn off the energy source. For gas, turn the control knob to "off" or "pilot." For electric, switch off the breaker for the heater.
- Keep clear of hot water. Tank water is often 120°F or hotter.
- Drain the tank if it's still leaking by attaching a hose to the drain valve and running it outside or to a floor drain.
Where it's leaking from matters
| Leak location | Likely cause | Urgency |
|---|---|---|
| Temperature/pressure relief valve or its discharge pipe | Excess pressure or a failing valve | Call a plumber; don't cap the pipe |
| Supply connections on top | Loose fitting or failed flex connector | Often a simple fix |
| Drain valve near the bottom | Worn valve or loose cap | Usually fixable |
| Bottom of the tank itself | Internal corrosion; the tank has failed | Replace the water heater |
Location changes the damage
Garage: water mostly runs across the slab and out the door, but check where it flowed toward the house and under the interior door. Interior closet or utility room: water wicks into the shared walls, baseboards and adjacent carpet within hours. Attic: many Mesquite homes have attic water heaters, and a failure there sends water through insulation and ceiling drywall into rooms below. See ceiling water damage.
Preventing the next one
- Most tank water heaters last roughly 8–12 years. The manufacture date is coded in the serial number on the label.
- A drain pan plumbed to the outside catches slow leaks; attic installations should always have one.
- An automatic leak-detection shutoff valve closes the supply when it senses water.
- Flushing sediment yearly extends tank life, especially with hard North Texas water.
Water heater let go? Shut off the supply and power, then call. Clean water from a tank is very salvageable if extraction starts quickly. Call (214) 910-5552, answered 24/7.