Symptom guide
Water heater leaking: identify the source first
A wet fitting, relief-valve discharge, condensate drain, and failed tank need different responses. Use the location and timing of the water to choose a guide.
Safety first: Keep away from hot discharge and wet electrical equipment. Shut off the cold inlet only if it is safely accessible; never cap a relief valve.
Start here
Identify the unit before following a procedure
Photograph the rating plate, control or display, and the exact symptom. Model generations can use different controls and code meanings even when the brand name is the same.
- Choose the heater typeGas tank, electric tank, tankless, heat pump, indirect, or RV.
- Record the exact clueCode, flash count, leak location, sound, or timing.
- Use the closest guideConfirm every model-specific step against the label or manual.
Gas
14 guidesCarbon Monoxide From the Water Heater
A CO alarm near a gas water heater can mean a blocked vent, backdrafting, a failed power-vent blower, or overfiring. What to do right away.
GasControl Box Leaking Gas? Get Out Now
A gas smell at a water heater control valve is an emergency. Leave the building and call the gas utility from outside. What not to do.
GasGas Smell After Water Heater Replacement
Mercaptan after a heater swap is a leak until a utility or licensed fitter says otherwise. Leave. Don’t sniff fittings.
GasReplace a Gas Water Heater Burner Assembly?
A rusty burner can signal a leaking tank rather than a bad burner. When a gas burner assembly is worth replacing, and when the tank is done.
RheemRheem Tankless Smells Like Gas? Leave
A gas smell at a Rheem tankless should be treated as a leak until a professional says otherwise. What to do, and which odors aren't gas.
RheemRheem Water Heater Smells Like Gas? Leave
A gas smell at a Rheem, Ruud, or Richmond water heater should be treated as a leak. What to do right away, and which smells are not fuel.
GasSmell Gas After Lighting the Water Heater?
A gas smell after lighting a water heater may be unburned fuel or a leak at the control. Why you should leave, not relight, and who to call.
GasSmell Gas When the Water Heater Turns On?
A gas smell only when the burner fires can mean a leak or delayed ignition. Why you should leave and call for help rather than keep cycling it.
GasTankless Exhaust Smells Like Gas? Leave
A gas smell at a tankless exhaust can mean unburned fuel or a leak. What to do right away, and which harmless smells are sometimes mistaken for gas.
GasWater Dripping on a Gas Water Heater Burner
Water near a gas burner may be condensation, tracked water, or a tank leak. Keep wet equipment off and have the source and combustion safety assessed.
GasWater Dripping on the Water Heater Pilot
A wet pilot is T&P tracking, draft-hood drip, or a tank leak at the door. Rust at the chamber means shut gas.
GasWater Heater Leaking From the Vent Collar
Water at a water heater vent collar can be condensate, rain, a fitting above, or a tank leak at the flue. When it becomes a CO concern.
GasWater Heater Vent Pipe Leaking? CO Risk
Water on a water heater vent pipe can be condensate, rain, or a failed joint. Why a leaking vent can be a carbon monoxide risk.
GasWater Leaking From the Gas Control Valve
Water on a gas control valve usually tracks from another fitting or a leaking tank. How to trace it, and why gas fittings should stay untouched.
Electric
8 guidesAO Smith E55 Code: Leak Detected
E55 on an A. O. Smith Energy Smart tank means the leak sensor found water. Shut off power, find the wet part, and learn when the tank is done.
A. O. SmithAO Smith Hybrid Problems: Codes
A. O. Smith Voltex hybrid not heating? Common causes are a dirty filter, vacation mode, an element or ECO fault, a compressor code, or a leak.
Bradford WhiteBradford White Water Heater Leaking From Thermostat
Water at a Bradford White thermostat can be a tank leak, element gasket, or fitting above it. Shut energy down.
ElectricElectric Heater Leaking at the Bottom Element
Water at the lower element is usually a flange gasket or the threads, not necessarily a failed tank. How to tell the difference safely.
ElectricElectric Water Heater Smells Like Gas?
A gas smell near an electric water heater is still an emergency: another appliance or line may be leaking. What the smell can mean and what to do.
ElectricHeating Element Stuck in the Water Heater?
A heating element that won't come out is usually seized by scale. When to stop before damaging the tank fitting and causing a leak.
SeiscoSeisco Tankless Water Heater Troubleshooting
A Seisco tankless not heating usually has a missing 240 V leg, air in the chamber, a high-limit trip (122), or a leak detect code (126).
ElectricWater Leaking From the Upper Thermostat
Water at the upper thermostat usually comes from an element gasket, a fitting above, or the tank itself. How to find the source with power off.
Tankless
13 guidesNavien Condensate Drain Leaking
A wet Navien condensate fitting is a trap, slope, freeze, or loose union — not always a dead exchanger. Fix the drain path first.
NavienNavien Constantly Running: Recirc or Leak
A Navien that never seems to stop is usually the recirculation pump. If the burner itself keeps firing, suspect a stuck flow sensor or a leak.
NavienNavien Leaking From the Bottom
Bottom drip on a Navien is condensate, a fitting, the PRV, or a heat exchanger. Identify the fluid, then shut it down.
NoritzNoritz Leaking From the Bottom
Water under a Noritz can be condensate, a relief valve discharge, a filter or drain plug gasket, or the heat exchanger. How to identify it.
RheemRheem Tankless Leaking Inside the Cabinet
Water inside a Rheem tankless cabinet can be condensate, relief valve discharge, an O-ring, or the heat exchanger. How to identify the source.
RinnaiRinnai Constantly Running: Recirc or Leak
A Rinnai that seems to run nonstop is usually recirculation or freeze protection. If the burner keeps firing, suspect a flow sensor or a leak.
RinnaiRinnai Leaking by Exhaust When Turned Off
Water at a Rinnai flue after shutdown is condensate, rain, or a cracked exchanger. Do not silicone the vent.
RinnaiRinnai Leaking From the Bottom
Water under a Rinnai can be condensate, relief valve discharge, or a heat exchanger or internal fitting leak. How to tell which you have.
RinnaiRinnai Tankless Water Heater Frozen
A frozen Rinnai needs power, freeze protection, and a leak check before restart. Do not fire a split unit;
RinnaiRinnai TPR Valve Leaking? Stop It Safely
A dripping Rinnai T&P valve means excess pressure or heat. Find the real cause, stop the leak path,.
TakagiTakagi Tankless Leaking: Find the Source
Water under a Takagi can be condensate, relief valve discharge, an O-ring at the filter or water valve, or the heat exchanger. How to tell.
TanklessTankless Leaking After a Freeze
A tankless leaking after a freeze is a split exchanger or fitting, not a drip to ignore. Shut water and power.
TanklessTankless Water Heater Smells Like Sulfur
Sulfur smell only in tankless hot water usually comes from well water or bacteria. A sulfur smell in the air may be a gas leak. How to tell.
RV
4 guidesRV Water Heater Leaking From the Bottom
Water at the bottom of an RV water heater can come from the drain plug, P&T valve, anode, bypass fitting, or the tank. How to find the source.
RVRV Water Heater Leaking Outside
Water under an RV water heater door can come from the drain plug, T&P, anode, element gasket, or the tank. How to find the wet part.
RVRV Water Heater Pressure Relief Dripping
An RV water heater relief valve that drips usually reacts to high city-water pressure, heating without an air pocket, or a dirty seat.
SuburbanSuburban RV Water Heater Leaking
A leaking Suburban RV heater may be a plug, relief valve, fitting, or split tank. Shut it down safely.
Troubleshooting
60 guidesAmerican Water Heater Troubleshooting
American water heaters share A. O. Smith hardware. Diagnose a cold, blinking, or leaking unit by reading the LED count and finding the wet part.
A. O. SmithAO Smith Leaking From the Bottom
Water under an A. O. Smith can come from the drain valve, T&P discharge, a fitting, an element gasket, or the tank. How to find the source.
TroubleshootingApartment Water Heater Not Working
Apartment water heater not working or leaking? How to make it safe, what to report to your landlord, and which repairs to leave to them.
AristonAriston Leaking From the Bottom
Water under an Ariston Andris, Velis, or Pro1 can come from the drain, T&P, a bottom fitting, or the tank itself. How to find the wet part.
AristonAriston Leaking From the Front Panel
Water at an Ariston front cover comes from behind it: an element gasket, thermostat pocket, or the tank. How to tell a gasket from a failed tank.
AristonAriston Pressure Relief Valve Leaking
An Ariston T&P valve that drips is reacting to pressure or temperature, often thermal expansion. Why it happens and why it must never be capped.
AristonAriston Water Heater Troubleshooting
An Ariston that is cold, leaking, or showing a fault needs a power, flow, sensor, or tank check. Photograph it.
BoschBosch Water Heater Troubleshooting
Bosch troubleshooting for Therm and Greentherm tankless, AquaStar, Powerstar electric, and Tronic mini-tanks. Codes, flow, power, and leaks.
Bradford WhiteBradford White Leaking From the Bottom
Water under a Bradford White can come from the drain valve, T&P discharge, a fitting, an element gasket, or the tank. How to find the source.
Bradford WhiteBradford White Leaking From the Top
A leak at the top of a Bradford White is usually the T&P, anode, a nipple, heat trap, or connector, not the tank. How to find the wet fitting.
Bradford WhiteBradford White Water Heater Beeping
ICON gas tanks don't beep. A beeping Bradford White is usually an Infiniti tankless, AeroTherm hybrid, power-vent board, or a leak sensor.
BuderusBuderus Indirect Water Heater Problems
Buderus Logalux no-heat is usually the sensor, DHW pump, or boiler priority — not a dead tank. Leak from the vessel means replacement.
TroubleshootingCan You Use Water If the Water Heater Is Leaking?
You can keep cold water on if you close the heater's cold inlet, but running hot water through a leaking tank empties it. What to do first.
TroubleshootingCold Water Inlet Leaking on the Heater
A leak at the cold water inlet is usually a dielectric nipple, heat trap, connector, or Hydrojet adapter, not the tank. How to find it.
TroubleshootingDrain a Water Heater With No Floor Drain
No floor drain? You can drain a water heater to a sink, tub, or toilet with a hose or pump. Safe steps, including shutting off power or gas first.
EnvirotempEnvirotemp Water Heater Troubleshooting
An Envirotemp heater that is cold, leaking, or locked out needs an exact model and symptom check. Stop unsafe resets.
TroubleshootingExpansion Tank Pinhole Leak: Replace It
A pinhole leak in an expansion tank shell means the tank needs replacing. How to isolate it safely and why patches aren't a fix.
TroubleshootingFactory Plastic Drain Valve Is Dripping
A dripping plastic drain valve at the bottom of a tank is usually the valve itself, not the tank. How to confirm and what to replace it with.
TroubleshootingHeater Connector Leaking, Not the Tank
A leak at a water heater's flex connector, dielectric nipple, or union is usually the fitting, not the tank. How to identify and isolate it.
TroubleshootingHow to Shut Off an Apartment Water Heater
Leaking apartment heater? Shut off cold water, then gas or the 240V breaker only if safely accessible. Notify the landlord immediately.
HTP / PhoenixHTP Phoenix Problems: Lockout to Leak
Phoenix lockouts are condensate, ignition, sensors, or scale — not a mystery board. Run this sequence.
TroubleshootingHydrojet Fitting Leaking, Not the Tank
A leak at a Bradford White Hydrojet fitting is usually the cold inlet nipple, dielectric, or adapter, not the tank. How to tell the difference.
KenmoreKenmore Water Heater Troubleshooting
Kenmore water heaters are built by A. O. Smith or Rheem. Identify the maker from the plate, then diagnose the LED, ECO, element, or leak.
TroubleshootingNew T&P Valve Still Leaking? Why
A new T&P that weeps is debris on the seat, still-high pressure, or no expansion tank. Do not cap it.
TroubleshootingNew Water Heater Has Water in the Pan
Water in the pan under a new heater is often condensation, T&P discharge, a loose fitting, or a drain valve, not a failed tank. How to tell.
RelianceReliance 6-06: No Heat, Light, or a Leak
The Reliance 6-06 is an A. O. Smith-built gas or electric tank. Diagnose no heat, the status light, or a leak by fuel type.
RelianceReliance Water Heater Leaking: Find the Source
A Reliance leak can come from the drain valve, T&P, a fitting, an element gasket, or the tank itself. How to find the wet part and what it means.
RheemRheem Plastic Drain Valve Leaking
Locate a possible Rheem drain-valve leak without forcing the valve. Distinguish tracked water, a leaking outlet, and a tank problem.
RichmondRichmond Water Heater Leaking: Find the Source
A Richmond leak can come from the drain valve, T&P, a fitting, an element gasket, or the tank itself. How to find the wet part and what it means.
RichmondRichmond Water Heater Troubleshooting
Richmond water heaters use Rheem hardware. Diagnose a cold, flashing, or leaking unit by fuel type: element, ECO, gas lockout, or leak.
RuudRuud Hot Water Heater Troubleshooting
Ruud is Rheem's wholesale brand. Diagnose a cold, flashing, or leaking Ruud by fuel type: element, ECO, gas lockout, or a leak.
TroubleshootingSharkBite Water Heater Connector Leaks
A leaking SharkBite water-heater connection needs its source and installation checked. Learn what to observe and when to arrange a repair.
SuperStorSuperStor Indirect Heater Problems Fix
SuperStor no-heat, leaks, and popping have a short list: aquastat, boiler priority, coil air, or a dead tank. Know when to stop DIY.
TroubleshootingT&P Leaking After You Tested It
You lifted the test lever and the T&P will not reseat — mineral on the seat, not a new tank. Do not cap it.
TroubleshootingT&P Leaking on a New Water Heater
A T&P valve weeping on a new heater usually means thermal expansion, high house pressure, or debris on the seat. Why it must never be capped.
TroubleshootingT&P Overflow Discharging? Do Not Cap It
A T&P overflow that keeps dumping is expansion, high psi, overheat, or a failed valve. Do not cap it.
Triangle TubeTriangle Tube Problems: No Heat to Leak
Triangle Tube units are indirects, combi boilers, or coils. Cold showers usually trace to a sensor, pump, 3-way valve, priority, or a lockout.
U.S. CraftmasterUS Craftmaster: No Heat, Flashes, or a Leak
U.S. Craftmaster tanks share A. O. Smith/State hardware. Diagnose a cold, blinking, or leaking unit by counting the LED and finding the wet part.
TroubleshootingWater Coming From the Top of the Heater
Water at the top of a tank heater is usually the T&P, anode, a nipple, heat trap, connector, or element gasket, not the tank. How to find it.
TroubleshootingWater Dripping From Water Heater Exhaust
Water dripping from a water heater exhaust can be normal condensate, rain, a blocked condensate drain, or a cracked heat exchanger.
TroubleshootingWater Dripping Inside the Water Heater
Water inside a water heater jacket may come from a nipple, element gasket, condensate, T&P, or the tank. How to find the source safely.
TroubleshootingWater Heater Alarm Going Off? Find the Beep
A beeping water heater is usually a tankless lockout, hybrid alarm, power-vent board, or leak sensor, or a nearby smoke or CO alarm.
TroubleshootingWater Heater Beeping After a Power Outage
A water heater beeping after an outage usually has a tankless or hybrid lockout, a dry-fire alarm, a power-vent fault, or a leak sensor alert.
TroubleshootingWater Heater Beeping and No Hot Water
Beeping with no hot water usually means a tankless or hybrid lockout, a dry-fire alarm, a power-vent fault, or a leak sensor that cut the heat.
TroubleshootingWater Heater Check Valve Leaking
A leak near a water heater check valve may be the valve body, a heat-trap nipple, or a recirculation check. How to isolate and identify it.
TroubleshootingWater Heater Dip Tube Failure Symptoms
A failed dip tube gives a short burst of hot water followed by lukewarm water. Symptoms, how to confirm it, and when to call a plumber.
TroubleshootingWater Heater Gasket Leak? Name the Seal
A gasket leak is an element, cleanout, or flue seal — not always a dead tank. Paper-towel the source.
TroubleshootingWater Heater Leaking After a Power Outage
A water heater leak after a power outage is often T&P discharge, a failed condensate pump, or freeze damage. How to find the source.
TroubleshootingWater Heater Leaking From an Outside Pipe
A wet pipe outside the tank is a nipple, T&P, drain, or outdoor union — not always a dead shell. Name it.
TroubleshootingWater Heater Leaking From the Top Plastic Plug
A leak at a plastic plug on top of a water heater is usually the anode, heat trap, or a capped port, not the tank. How to identify it.
TroubleshootingWater Heater Leaks When the Washing Machine Runs
A leak that appears only when the washer runs is often T&P discharge from a pressure spike, a connector, or the washer's own hoses.
TroubleshootingWater Heater Making a Hissing Noise?
A hissing water heater can mean sediment, a simmering T&P, steam from a leak, or a gas leak. How to tell which, and when to shut it down.
TroubleshootingWater Heater Problems in a Crawl Space
Leaks, no heat, or venting problems with a crawl-space water heater. What to do first, and when access issues mean calling a licensed plumber.
TroubleshootingWater Heater PVC Pipe Leaking? Name It
A PVC pipe leaking at a water heater may be a condensate drain, a vent joint, or a T&P discharge line. How to tell which pipe and why it matters.
TroubleshootingWater Heater Smells Like a Dead Animal?
Rotten-egg HOT water is the anode. Mercaptan in AIR is a gas leak — leave. A rodent in the FVIR is different.
TroubleshootingWater Heater Sounds Like Running Water
A water heater that sounds like running water with taps closed may be discharging its T&P, running recirculation, or leaking. How to find it.
TroubleshootingWater Leaking From the Bottom of the Tank
A puddle beneath a water heater can come from several sources. Identify exterior clues, urgent hazards, and when repair or replacement is appropriate.
Weil-McLainWeil-McLain Water Heater Leaking: Find It
A Weil-McLain AquaPlus leak can come from the drywell plate, anode port, T&P, a coil union, or the vessel. How to identify the source.
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.
WhirlpoolWhirlpool Water Heater Troubleshooting
Whirlpool water heaters use A. O. Smith/American hardware. Diagnose gas and Energy Smart electric models by LED, ECO, element, or leak.