Symptom-first guidance · tank · tankless · RV
What’s wrong with your water heater?
Start with the symptom you can see. Get the likely cause, the checks that are safe to make, and a clear point where a licensed plumber should take over.
Start with an exterior observation. Keep covers closed.
A better first visit
Start here
What is your water heater doing?
A clearer way to troubleshoot
Start with what changed, then narrow the system.
Water heaters rarely fail with a helpful label. A cold shower, wet pan, blinking light, or strange sound is the starting clue. The useful next step is matching that clue to the heater type, energy source, and timing of the failure.
Our guides are built for that first pass: identify the symptom, make the safe observations, and stop before the job moves into gas, high voltage, combustion, or pressure work.
How we build the guidesEvery useful diagnosis answers
- What changed?Noise, leak, code, temperature, or ignition.
- What can I safely see?Controls, shutoffs, water source, and timing.
- Where should I stop?Know when a licensed technician needs to take over.
Browse by system
Go straight to your heater type.
Troubleshooting
Leaks, noises, codes, shutdowns, and the fastest safe first checks.
View guides 305 guidesGas
Pilots, burners, ignition faults, gas odors, and venting problems.
View guides 112 guidesTankless
Flow faults, cold showers, lockouts, condensate, and brand codes.
View guides 213 guidesElectric
Breakers, elements, thermostats, ECO trips, and heat-pump units.
View guides 41 guidesRV
Atwood, Suburban, Truma, Dometic, and coach water-heater faults.
View guidesBrowse by manufacturer
Find the name on the rating plate.
Most useful first reads
Useful first reads
Rheem Water Heater Not Heating
A Rheem not heating needs different checks for gas and electric: breaker, ECO, elements, and thermostat, or pilot, FVIR, and gas control.
Read diagnosis TroubleshootingWhat To Do If a Water Heater Bursts
If your water heater bursts, close the cold inlet, shut off the power or gas, and keep clear of the water. Step-by-step first actions.
Read diagnosis GasWhy Won't My Gas Water Heater Stay Lit?
A gas water heater that lights then dies is thermocouple, thermopile, draft, or the gas valve. If you smell gas, leave.
Read diagnosis ElectricHeater Trips Breaker After a Few Minutes
A delayed breaker trip can have several electrical causes. Learn what to record, why repeated resets are unsafe, and what a technician should check.
Read diagnosis TanklessRinnai Error Code 12: Flame Failure
Rinnai code 12 means the burner lit and then lost flame. Common causes like gas supply, venting, or a dirty flame rod, and when to stop resetting.
Read diagnosis RVAtwood RV Water Heater Troubleshooting
Atwood/Dometic RV water heater not working? Split the problem into gas, electric, ECO, or bypass, then follow the matching checks.
Read diagnosisBefore you begin
Common questions about troubleshooting.
Can I troubleshoot a water heater myself?
You can safely identify the heater type, read the display or status light, check an accessible shutoff, and note when the problem started. Stop before gas controls, combustion, 240-volt covers, pressure devices, or any area with water near electricity.
Why does resetting the heater often fail?
A reset clears a safety device; it does not repair the condition that caused the trip. A repeated trip can point to a shorted element, blocked vent, flame-sensing fault, dry-fire condition, or unsafe temperature or pressure problem.
How do I know whether my heater is gas or electric?
Look for a gas pipe and burner or vent assembly, or a dedicated double-pole electrical breaker and access panels. Do not remove covers to identify it. The rating plate usually names the fuel and model safely from the outside.
When is a water-heater leak urgent?
Treat a leak from the tank shell, a streaming temperature-and-pressure valve, water near electrical equipment, or flooding that cannot be isolated as urgent. Close the cold inlet only if you can do it safely, keep clear of hot discharge, and call a qualified professional.
Safety before diagnosis
Smell gas, see flooding, or hear a burner bang?
Leave the area when gas is involved, shut off water or power only when you can do it safely, and get a licensed professional involved.