Water on the floor next to a water heater sends most people straight to the phone. Sometimes that is exactly right. Other times the tank is fine and the water is condensation or a slow drip from a part that costs far less than a heater.
Pipe Dream Plumbing Co. answers water heater calls across San Diego County and the Temecula Valley. Here is how to tell which situation you have, and the shutoff steps that keep a real leak from getting worse while you wait for us.
This article is part of our Water Heater Guide, which covers the whole topic and links every article on it.
How do I know if a water heater leak is an emergency?
Find where the water starts. Water from the tank body, a steady flow, or any leak in an attic, upstairs closet or near electrical is an emergency. A slow drip from a fitting or the relief valve pipe usually is not.
Dry the area with a towel, then watch. Look at the pipe connections on top, the relief valve on the side and its discharge pipe, the drain valve near the bottom, and the tank itself. Water runs down the outside of the jacket, so the puddle is often far from where it started.
Location changes the urgency as much as the cause does. A slow leak in a garage with a drain pan is an annoyance. The same leak in a hallway closet is soaking into the floor right now.
How do I shut off a leaking water heater?
Turn off the heat first: the gas control or gas valve on a gas heater, the breaker on an electric one. Then close the cold water valve on the pipe going into the top, and open a hot tap in the house to drop the pressure.
On a gas heater, turn the control knob to off, or turn the handle on the gas supply valve so it sits across the pipe. On an electric heater, switch off its breaker in the panel. Heat comes first because a tank that is draining with the burner or elements on can damage itself.
If the cold water valve will not turn, close the main shutoff for the house. If the tank itself is leaking and you are comfortable doing it, run a garden hose from the drain valve to a floor drain or outside and open it. The water is hot, so let it cool if you can and keep children and pets clear. If you smell gas, skip all of this, leave the house and call your gas utility or 911 from outside.
Where is the water coming from, and what does it mean?
The source tells you almost everything. The table below matches the spot to the usual cause and whether it needs an urgent call.
| Where the water is | What it usually means | Emergency? |
|---|---|---|
| Tank body or bottom seam, fittings dry | The inner tank has failed | Yes. Shut it down; the tank needs replacing |
| Pipe connections on top | Loose or corroded fitting or connector | Usually not. Close the cold valve if it is steady |
| Relief valve pipe, a drip now and then | Pressure spikes or a worn valve | No, but book a visit |
| Relief valve pipe, steady hot water or steam | Tank overheating or a control failure | Yes. Turn off the heat source now |
| Drain valve near the bottom | Valve weeping | No. Cap it and book a visit |
| Drops near the burner after a big draw, gone once hot | Condensation | No |
When you cannot find the source, treat it as an emergency until you can. A puddle with no obvious start is the one most likely to be the tank.
Water on the floor and not sure where it is coming from? Shut the heater down and call us. We will find the source and tell you whether it is a part or the tank.
Why is a dripping relief valve not always an emergency?
Because the valve is doing its job. An occasional drip usually means pressure is spiking when the water heats, often from a missing or failed expansion tank or high street pressure, or the valve is simply worn.
The temperature and pressure relief valve lets water out so the tank does not have to. A drip now and then is a warning, not a failure. We check the house pressure and the expansion tank and replace the valve if it is worn.
Never cap, plug or tie off the valve or its pipe to stop a drip. That removes the one safety device keeping an overheated tank in check. A steady stream of very hot water or steam is different: turn off the heat and call right away.
How can I tell condensation from a real leak?
Condensation shows up after a lot of hot water has been used and the tank refills with cold water. It collects near the burner, may sizzle, and dries up once the tank is back to temperature.
Wipe everything dry, put a paper towel on the floor at the base and check it over a day. If it stays dry once the heater has caught up, you saw condensation. If it keeps getting wet, something is leaking.
Tankless and high-efficiency units also have a condensate line that drips by design. As long as it runs to a drain, that water is normal.
What happens if the tank itself is leaking?
It needs replacing, because a leaking tank cannot be repaired. Our water heater installation starts at $750 installed, with the unit, permit and haul-away included, and most tank replacements run $750 to $2,500.
If it turns out to be a fitting or a valve, we fix that and leave the heater alone. We do water heater repair and replacement and take emergency plumbing calls, from water heater service in Escondido to Murrieta. Our troubleshooting post covers no-hot-water problems that come without a leak.
Leaking water heater? Shut off the heat and the cold water valve, then call Pipe Dream Plumbing Co. at (858) 330-2881. We will tell you whether it is a repair or a replacement.
