Short answer: the biggest warning signs are water pooling around the base of the tank, rusty or discolored hot water, popping or rumbling noises, and a tank that's more than 10 years old. A leak from the tank itself means it's time to replace it soon, before it fails and floods the garage or closet. Some other problems, like a faulty valve or a worn heating element, can be repaired.
How long water heaters last
Most tank water heaters last about 8 to 15 years. Gas tanks tend toward the shorter end, electric tanks toward the longer end. Hard water, skipped maintenance, and a missing or failed expansion tank can shorten that.
You can usually find the install date on the label on the side of the tank. If you can't read it, the serial number often encodes the year. If yours is past 10 years and showing any of the signs below, start planning for a replacement instead of waiting for an emergency.
7 warning signs to watch for
- Water around the base of the tank. Check where it's coming from. A drip from a fitting or the relief valve can often be fixed. Water seeping from the tank body means the inner tank is corroding through, and it can't be repaired.
- Rusty or brown hot water. If only the hot side looks rusty, the tank may be rusting from the inside. Rust at the fittings or around the base is another clue.
- Popping, banging, or rumbling. Sediment builds up on the bottom of the tank over time. As the burner or element heats through it, you hear popping. Heavy sediment makes the heater work harder and wears it out faster.
- Not enough hot water. Showers running cold sooner than they used to can mean sediment is taking up space in the tank, or a heating element or thermostat is failing.
- Water that's too hot or temperature swings. A failing thermostat or control can cause this. It's worth a look, since scalding water is a safety issue.
- A leaking or dripping relief valve. The temperature and pressure relief valve is a safety device. If it's dripping or discharging, the tank may be overheating or building too much pressure. Call a pro rather than capping it.
- Age plus repairs. A tank over 10 years old that needs an expensive part is usually a better candidate for replacement than repair.
Repair or replace?
Some problems have simple fixes: a new thermostat, heating element, gas valve, or relief valve. A tank that is leaking from its body, rusting inside, or past its expected life is usually a replacement.
At Green Core, a standard gas or electric tank water heater replacement starts at $2,850, installed. See our water heater replacement cost guide for what affects the price.
Thinking about an upgrade?
If your tank is near the end, it's a good moment to look at your options:
- Heat pump water heaters use far less energy than a standard electric tank and often qualify for rebates. We install models like SANCO2 and GE GeoSpring.
- Tankless water heaters give you endless hot water and take up less space, though they cost more up front.
- Another tank is the fastest and lowest-cost option. We install Bradford White and American Standard, and same-day replacement is often possible when our schedule allows.
Common questions
Can a leaking water heater be repaired?
It depends on where the leak is. Leaks from fittings, valves, or the drain valve can often be repaired. A leak from the tank itself can't be fixed, and the heater should be replaced.
Is it dangerous if my water heater is making noise?
Popping from sediment usually isn't dangerous by itself, but it means the heater is working harder and wearing out. Loud banging, a dripping relief valve, or a gas smell should be checked right away.
How fast can Green Core replace a water heater?
We offer same-day water heater replacement in Sonoma and Marin when our schedule allows.
Should I drain my water heater every year?
Flushing the tank yearly helps clear sediment and can extend its life, especially with hard water. If a tank has gone many years without flushing, ask a pro first, since old drain valves can stick or leak.
Seeing any of these signs? Call Green Core at (707) 988-5858 for a water heater check or a same-day replacement quote.