Water heater problems
Most water heater problems come down to five causes: a failed heating element or thermostat (electric), a failed thermocouple or gas valve (gas), sediment buildup in the tank, a spent anode rod, or a tank that has rusted through. Only the last one forces replacement - the rest are usually repairable.
No hot water at all. On an electric unit, this is most often a tripped breaker, a tripped high-limit reset, or a dead upper heating element. On a gas unit, the pilot or igniter has failed or the gas control valve has. All of these are diagnosable in a normal service call.
Water in the drip pan or on the floor. Find out where it is coming from before you panic. A dripping temperature and pressure relief valve or a leaking supply connection is a repair. Water seeping from the bottom of the tank body itself is a failed tank, and that means replacement. There is no patch for a rusted tank.
Rumbling, popping, or banging. That is sediment on the tank floor, with water boiling underneath it. It reduces capacity, wastes energy, and shortens tank life. Flushing helps; if it has been ignored for years, it may not fully clear.
Anything involving gas smell, soot, or a CO alarm is not a plumbing problem - it is an evacuate-and-call problem. Leave the house, then call your gas utility's emergency line from outside. CPSC has recalled gas tankless water heaters for carbon monoxide hazards, including a 2026 recall of VST-brand units, so a CO issue traced to a water heater is not a far-fetched scenario. Never troubleshoot combustion or venting yourself.
Choosing water heater a fix
The judgement calls that decide the bill, before anyone quotes you.
- Locate the leak before you accept a diagnosis Top-of-tank fittings and the T&P valve are repairable. The tank body is not. A contractor should be able to show you which it is.
- Note the unit's age before you spend on repair There is a date code on the data plate. NerdWallet puts tank life at roughly 10-15 years. Repairing a 14-year-old tank rarely pays.
- Treat lukewarm water on a gas unit as a real symptom It can be sediment, a failing dip tube, or a partly failed gas valve. Do not just crank the thermostat up - that raises scald risk without fixing the cause.
- Smelly hot water is usually the anode rod A rotten-egg smell in hot water only is typically bacteria reacting with the magnesium anode. It is a known, fixable issue - ask about an anode rod change rather than replacing the heater.
- Never bypass or cap a T&P valve If the temperature and pressure relief valve is discharging, something is wrong with pressure or temperature. Capping it turns a nuisance into a genuine explosion hazard. Get it diagnosed.
All water heater problems
No Hot Water
Water Heater Leaking
Water Heater Making Noise
Rusty Hot Water
Pilot Light Wont Stay Lit
Not Enough Hot Water
Water Too Hot
Water Heater Smells
Where these figures come from
Sources last checked
- NerdWallet - Water Heater Cost in 2026 · retrieved 2026-07-25
- CPSC - VESTA.DS Recalls VST Brand Tankless Water Heaters Due to Carbon Monoxide Hazard (2026) · retrieved 2026-07-25
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