Water Heater — No Hot Water
Your water heater isn't producing hot water or runs out quickly.
Water Heater — No Hot Water: No hot water is usually caused by a failed heating element (electric), a bad thermocouple or pilot light issue (gas), or a depleted tank. Check the pilot light on gas units or the breaker on electric units first. Repairs cost $150–$500. If the tank is over 10 years old and leaking, replacement ($1,200–$4,500) is recommended.
What Causes This?
Failed Heating Element (Electric)
Electric water heaters have upper and lower heating elements. If one fails, you get lukewarm water. If both fail, no hot water at all.
Pilot Light Out (Gas)
The pilot light ignites the main burner. A draft, dirty pilot orifice, or failed thermocouple can extinguish it. Most homeowners can relight following tank instructions.
Bad Thermocouple (Gas)
The thermocouple senses the pilot flame and keeps the gas valve open. A faulty one shuts off gas flow even when the pilot is lit.
Sediment Buildup
Minerals from hard water settle at the bottom of the tank, insulating the burner or elements from the water and reducing heating efficiency.
Undersized Tank
A tank that's too small for your household runs out of hot water during peak use. This is an ongoing problem, not a sudden failure.
Faulty Thermostat
The thermostat controls when the burner or elements activate. A failed thermostat can prevent heating or cause overheating.
Can It Wait?
No hot water is uncomfortable but not dangerous unless the tank is actively leaking. A leaking water heater should be shut off immediately (gas and water supply) to prevent flooding.
What Does It Cost?
| Item | Cost Range |
|---|---|
| Thermocouple Replacement | $100–$200 |
| Heating Element Replacement | $150–$300 |
| Thermostat Replacement | $150–$300 |
| Tank Flush (sediment) | $100–$200 |
| Tank Water Heater Replacement | $1,200–$2,500 |
| Tankless Water Heater | $2,500–$4,500 |
| Heat Pump Water Heater | $2,500–$4,500 |
Repair vs. Replace
Repair
Repair if: the tank is under 8 years old, the issue is a thermocouple, element, or thermostat, and the tank itself isn't leaking.
Replace
Replace if: the tank is over 10 years old, it's leaking from the tank body (not connections), or you want to upgrade to tankless or heat pump for long-term savings.
Rule of thumb: Tank water heaters have 8–12 year lifespans. If yours is approaching that age, replacement is usually smarter than a $300+ repair.
When to Call a Contractor
- ✓You've relighted the pilot and it goes out again
- ✓The tank is leaking from the bottom or sides
- ✓Water is discolored (rusty) coming from hot taps only
- ✓The water heater is making popping or banging sounds
- ✓You have no hot water and can't identify the cause
Related Problems
Water Heater — No Hot Water — FAQ
Why does my water heater run out of hot water quickly?
Common causes include a failed lower heating element (electric units), sediment buildup reducing tank capacity, a malfunctioning dip tube (incoming cold water mixes with hot), or a tank that's simply too small for your household. A plumber can diagnose the issue and recommend a fix.
Should I repair or replace my water heater?
Replace if the tank is over 10 years old, leaking from the body, or making rumbling noises (sediment buildup). Consider a heat pump water heater with SMUD rebates up to $4,000 — the payback is often under 3 years.
How long does a water heater last?
Tank water heaters last 8–12 years. Tankless models last 20+ years. Regular flushing (annually) extends tank life by 2–3 years by removing sediment buildup.