Shutting down a leaking water heater
Close the cold-water inlet
The valve on the cold pipe at the top of the tank stops new water from entering.
Turn off the heat source
Gas: set the control knob to off or pilot. Electric: switch off the dedicated breaker. Never heat a tank that may be draining.
Be careful of hot water
Water from the tank or relief valve can scald. Keep children and pets out of the garage or closet.
Contain the water
Use towels and a bucket. If the tank sits in a drain pan, check that the pan's drain line is clear.
If you smell gas, leave
Go outside and call 911 or SoCalGas. Do not try to relight anything.
Where is it leaking from?
| Leak location | Likely cause | Usually repairable? |
|---|---|---|
| Pipe connections on top | Loose fitting or worn connector | Often yes |
| Temperature and pressure relief valve or its discharge pipe | Valve doing its job, or a failing valve | Often yes, but the cause needs checking |
| Drain valve near the bottom | Worn or loose drain valve | Often yes |
| Seam or body of the tank | Internal corrosion | No; the tank needs replacement |
| Puddle with no obvious source | Could be condensation or a nearby line | Depends on what the plumber finds |
Hard water and tank life in Fullerton
Fullerton's water comes from local groundwater blended with imported water, and it is hard. Minerals settle as sediment at the bottom of a tank, which can make a heater rumble, reduce efficiency and contribute to wear. Flushing the tank on a regular schedule is one way owners try to slow that buildup.
A leak from the tank body is not something to patch. At that point the conversation is about replacement, and whether a like-for-like tank or a different type of heater makes sense for the house.
Replacing with a tank or going tankless
This is usually a planned decision, not a midnight one. A temporary shutdown buys time to compare.
Tank replacement
- Usually fits the existing space and connections
- Often the quickest way to restore hot water
- Needs seismic straps and proper venting for gas units
- Stores a set volume of hot water
Tankless
- Heats water on demand
- May require changes to gas line, venting or electrical service
- Hard water makes descaling maintenance important
- Installation is typically more involved than a swap
Questions to ask the plumber
- Is the leak from a fitting or valve, or from the tank itself?
- If repairable, what part failed and why?
- If replacement is needed, does the quote include seismic straps, venting and haul-away?
- Is a permit required for this replacement? Check with the city if unsure.
- Can you restore cold water to the house while the heater is off?
Common questions
Can I still use cold water with the heater shut off?
Usually yes. Closing the heater's cold inlet isolates the tank while the rest of the house keeps cold water.
The relief valve is dripping. Is that dangerous?
The valve releases water when temperature or pressure is too high, or when it is worn. Shut down the heater and have a plumber find out which it is.
How do I know how old my water heater is?
The label on the tank usually lists a serial number that encodes the manufacture date. A plumber can read it for you.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.