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Warning signs · Erie, PA

Leaking? Rusty? Banging?Signs your water heater is failing, and what to do right now.

Water heaters usually warn you before they quit. Here's what each symptom tends to mean, which are fixable, which mean replacement, and the exact steps to take if your tank is leaking right now.

  • Leak first aid
  • Symptom decoder
  • Repair vs replace

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Leaking right now?

Do this first.

  1. Stay safe. If you smell gas, leave the home and call your gas utility from outside. Keep clear of standing water near outlets or the heater's wiring.
  2. Shut off the cold water supply valve on the pipe entering the top of the tank.
  3. Cut the energy. Electric: switch off the water heater's breaker. Gas: turn the gas control knob to OFF (or PILOT), or close the gas shutoff on the line to the heater.
  4. Find the source. Fittings on top, the T&P valve or its pipe, the drain valve, or the tank body. Dry fittings with water under the tank usually means the tank is leaking.
  5. Limit damage. If water is spreading, attach a garden hose to the drain valve and drain to a floor drain or outside. The water can scald; let it cool if you can.
  6. Arrange service. A tank-body leak means replacement. Use the form above to request quotes.
Never cap, plug, or remove the T&P relief valve or its discharge pipe. It's the safety device that keeps an overheated tank from becoming dangerous.

Interactive symptom check

Repair or replace?

Five questions. Your answers get added to the quote form.

Question 1 of 5

How old is the tank?

Symptom decoder

What your water heater is telling you.

SymptomCommon causesUsually
Water under the tank, fittings dryCorroded tank bodyReplace
Drip at top fittingsLoose or corroded connectionsOften repairable
Water from T&P discharge pipeHigh temperature or pressure, thermal expansion, failing valveDiagnose promptly
Drain valve drippingWorn or debris-fouled valveRepairable
Rusty hot water onlySpent anode, internal tank corrosionReplace if tank is old
Rotten-egg smell (hot side)Anode reaction with waterOften fixable
Popping, rumblingSedimentFlush; replace if severe and old
Runs out fastSediment, dip tube, element, thermostat, undersizedDiagnose
Lukewarm water / temperature swingsThermostat, element, dip tube, mixing valveOften repairable
No hot water (gas)Pilot, thermocouple, gas valve, supplyOften repairable
No hot water (electric)Breaker, high-limit, elementsOften repairable
Soot, scorching, gas odorCombustion or venting problemUrgent professional check
Rust on the tank jacket or fittingsOngoing small leaks, condensation, corrosionInspect; may signal end of life
Age past 10–15 yrs (tank)End of typical life[1]Plan replacement
Cutaway illustration of a tank water heater

Inside the tank

Tap a part. See what fails.

Prevention

Make the next one last.

  • Flush sediment periodically per the manufacturer's manual.
  • Check the anode rod every few years and replace it before it's gone.
  • Test the T&P valve as the manual directs, carefully: discharge water is hot.
  • Control thermal expansion on closed systems with an expansion tank where required.
  • Set a sensible temperature; hotter settings raise scald risk and energy use.
  • Descale tankless units on the manufacturer's schedule.

When to replace

Signs it's time.

Replace when the tank body leaks, when rusty hot water shows up on an older tank, when repairs keep stacking up, or when the tank is past its expected life and you'd rather plan the swap than mop the basement. If you're replacing anyway, compare tankless and heat pump or fuel options, and review the cost factors.

Symptom by symptom

Cause, check, next step.

1. Water leaking around the tank

Likely causes: loose or corroded fittings at the top, a dripping drain valve, discharge from the T&P valve, condensation, or a corroded tank body. What to check: dry everything with a towel, then watch. Water appearing at the top fittings or drain valve points to a part; water seeping from under the jacket with dry fittings points to the tank. Condensation can show up on a gas tank when cold water first fills it and usually stops as the tank heats. Next step: fittings and valves are often repairable; a tank-body leak means replacement.

2. Rusty or discolored hot water

Likely causes: a spent anode rod and corrosion inside the tank, or rust from galvanized piping. What to check: run cold water alone from the same faucet. If cold is clear and only hot is rusty, the water heater is the likely source. Next step: on a young tank, an anode replacement may be worth discussing; on an older tank, rusty hot water is a strong replacement signal. Erie Water Works' supply is surface water from Lake Erie,[2] so rust that only shows up on the hot side is unlikely to be coming from the source water itself.

3. Rotten-egg or sulfur smell

Likely cause: a reaction between the anode rod and the water producing hydrogen sulfide, most noticeable on the hot side. What to check: whether the smell is hot-only (water heater) or both hot and cold (water supply, especially on private wells). Next step: anode changes are a common fix; have it evaluated. A gas smell near the heater is a different emergency (see below).

4. Popping, rumbling, crackling, or banging

Likely cause: sediment on the tank bottom; water trapped under it flashes to steam when the burner or lower element fires. What to check: whether noise happens during heating cycles. Next step: flushing can help early; years of hardened sediment may not flush out and keeps stressing the tank bottom.

5. Lukewarm water or hot water runs out fast

Likely causes: a failed lower element or thermostat (electric), a burner or gas control problem (gas), a broken dip tube mixing cold water into the top, sediment taking up volume, a thermostat set too low, or a household that has outgrown the heater's first-hour rating.[3] Erie factor: colder incoming water in winter means longer recovery; a tank that was fine in summer can struggle in February.

6. No hot water at all

Gas tank: the pilot may be out, the thermocouple or flame sensor failing, the gas control faulty, or gas supply off. Relight only by following the instructions on the heater's label. Electric tank: check the breaker; the high-limit (reset) switch may have tripped, which often points to a failed thermostat or element. Tankless: look at the display for an error code and check the manual; common categories include ignition, flame, venting, and overheat/scale faults. Gas and electrical diagnosis is a job for a qualified technician.

7. Pilot light won't stay lit

Likely causes: a weak thermocouple, a dirty pilot assembly, a draft blowing out the flame, or a venting or combustion-air problem. Some newer gas heaters have flammable vapor sensors that shut the unit down if air intake screens are clogged or vapors are detected. Next step: usually repairable; but repeated outages with soot or scorching need prompt professional attention.

8. T&P valve dripping or discharging

Likely causes: excessive temperature, high system pressure, thermal expansion in a closed system, or a worn valve. Never cap or plug the discharge pipe. Next step: get it diagnosed; it may need an expansion tank, pressure control, or a new valve, and if the tank is overheating, the controls need attention.

9. Temperature swings

Thermostat or element faults, a failing gas control, a mixing valve problem, or a damaged dip tube. Scald risk rises if the water gets suddenly hotter; don't simply crank the thermostat to compensate.

10. Corrosion, scorching, or soot

Rust at the fittings or around the base suggests ongoing leaks. Scorch marks or soot around the burner door point to combustion or venting trouble, which is a carbon monoxide risk; stop using the heater and get it inspected.

Gas smell or CO alarm: act now

  • Gas smell: leave the home without operating switches, and call your gas utility or 911 from outside.
  • CO alarm sounding: CPSC says move outside to fresh air immediately, call 911 or the fire department, account for everyone, and don't go back in until responders say it's safe.[4]
  • Don't use a suspect appliance again until it has been serviced by trained personnel.[4]

Carbon monoxide basics

CO is colorless and odorless and is produced by incomplete burning of fuels including natural gas and propane; CPSC lists malfunctioning water heaters among the fuel-burning appliances involved in CO poisonings.[4] Early symptoms resemble the flu without fever: headache, fatigue, shortness of breath, nausea, dizziness.[4]

CPSC recommends a CO alarm meeting UL 2034 on every level of the home and outside sleeping areas, with battery backup, and an annual professional inspection of fuel-burning appliances, including checks of flues and vents for blockage, corrosion, and disconnections.[4] CPSC does not recommend placing CO alarms directly above fuel-burning appliances.[4]

Emergency shutoff, step by step

  1. Water: close the cold-water inlet valve at the top of the heater. If it won't turn or is leaking, close the home's main water shutoff.
  2. Electric heater: turn off the dedicated breaker.
  3. Gas heater: turn the control knob to OFF; or close the gas shutoff valve on the supply line (handle perpendicular to the pipe is closed).
  4. Tankless: close the isolation valves and switch off power to the unit.
  5. Drain if needed: hose from the drain valve to a floor drain or outside; open a hot faucet upstairs to let air in. Water may be scalding.
  6. Document: photos of the label and the leak help your quote.

When to call for replacement quotes

Any tank-body leak; rusty hot water on an older tank; repeated repairs; a tank past its typical 10–15 year life;[1] or symptoms you'd rather not gamble on before winter.

Anode rod

The part that dies first.

Steel tanks are protected by a sacrificial anode rod, usually magnesium, aluminum, or zinc, that corrodes in place of the tank. A. O. Smith explains that the anode "sacrifices itself" by giving up ions so the steel isn't eaten away, and that how long it lasts depends on water chemistry, how much hot water is used, and whether a water softener is installed.[5]

Signs the anode is depleted

  • Rusty or discolored hot water while cold water is clear
  • Rotten-egg smell on the hot side (an anode-water reaction)
  • An older tank that has never had its anode checked

Inspection

DOE's Energy Saver guidance lists inspecting the anode rod every three to four years as routine storage-tank maintenance;[6] A. O. Smith recommends inspecting it once a year.[5] A. O. Smith says a healthy rod is smooth and about half an inch in diameter, and one with significant deterioration or several inches of exposed core wire should be replaced.[5] Removing an anode takes the power or gas off, partial draining, and real torque; many owners leave it to a technician.

Replace the rod or the tank? An anode swap makes sense on a tank young enough to be worth protecting. Once the steel is rusting through, a new anode won't undo it.

Sediment and flushing

Minerals settle to the bottom of a tank, reducing efficiency, causing popping noises, and stressing the tank floor. A. O. Smith says most tank water heaters need flushing at least once a year, more often with hard water.[5] EPA WaterSense also suggests flushing once a year after turning off power, using a garden hose to empty into a space that can handle hot water.[7] DOE's guidance mentions draining a quart from the tank every three months as routine maintenance.[6] Always follow your owner's manual.

Caution on old tanks: on a neglected older tank, opening the drain valve can stir up heavy sediment or reveal a valve that won't reseal. If your tank is past its typical life and has never been flushed, a professional assessment may be wiser than a first-ever flush.

Tankless descaling

Tankless units don't need flushing because they have no tank, but A. O. Smith notes many require descaling, at a frequency that depends on type and model.[5] Scale on the heat exchanger reduces efficiency and can trigger overheat or flow-related error codes. Descaling generally uses the isolation (service) valves, a pump, and a descaling solution per the manufacturer's instructions.

Age check

How old is your tank?

Find the rating plate on the side of the heater and read the serial number. Most brands encode the manufacture date there, each differently:

BrandHow the serial shows the date
RheemFirst two digits = month, next two = year (e.g., 1209… = December 2009).[8]
A. O. SmithFirst two digits = year, next two = week of manufacture (e.g., 2037… = week 37 of 2020).[9]
Bradford WhiteFirst letter = year, second letter = month; letters repeat every 20 years (e.g., A = 2004 or 2024), so pick the date that makes sense.[10]
Other brandsCheck the manufacturer's website or give the serial to the installer.

Compare the age with the typical 10–15 year life of a tank water heater (tankless units can run up to about 20).[1][11]

Repair or replace: a checklist

Lean repairLean replace
Tank under about half its expected lifeTank at or past 10–15 years[1]
Failed element, thermostat, thermocouple, gas controlWater leaking from the tank body
Dripping drain or relief valveRusty hot water on an older tank
Odor fixable with an anode changeRepeated repairs stacking up
One-time issue, otherwise healthyHousehold outgrew the first-hour rating[3]
 Planning a fuel switch, heat pump, or tankless anyway

Routine checks that catch problems early

  • Look for leaks, aged gaskets, loose connections, and corrosion regularly (EPA WaterSense).[7]
  • Check the T&P valve: EPA suggests at least annually;[7] DOE's guidance lists every six months.[6]
  • Anode: every 1–4 years depending on the source above.
  • Gas units: CPSC urges a yearly professional inspection of fuel-burning appliances, including flues and vents.[4]

Spotted a sign?

Get a free quote before a slow leak becomes a flooded basement.

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FAQ

Symptom questions.

See every FAQ →

Is a leaking water heater an emergency?

A leak from the tank body is a failure in progress and can get worse quickly; shut off the water supply and the fuel or power and arrange replacement. A drip from a fitting or valve may be repairable but should be checked soon.

Why is only my hot water rusty?

Rust only on the hot side points to the water heater, often a depleted anode rod or corrosion inside the tank. On an older tank, rusty hot water is a strong replacement signal.

Why does my hot water smell like rotten eggs?

Often a reaction between the anode rod and the water supply produces a sulfur smell in the hot water. It's commonly addressed by changing the anode type, but have it checked. A gas smell near the heater is different: leave and call the gas utility from outside.

Why is my water heater making popping noises?

Sediment on the bottom of the tank traps water that boils through it when the burner or lower element heats. It wastes energy and stresses the tank floor.

Why did my hot water run out so fast?

Common causes include sediment taking up tank volume, a broken dip tube, a failed lower element (electric), a thermostat problem, or a household that's outgrown the heater's first-hour rating.

Why is there no hot water at all?

Gas: pilot out, thermocouple or gas valve problem, or no gas supply. Electric: tripped breaker, tripped high-limit, or failed elements. Tankless: error code, ignition issue, or scale. A professional should handle gas and electrical diagnosis.

Water is dripping from the T&P valve pipe. What does it mean?

The temperature and pressure relief valve is releasing because of high temperature, high pressure (including thermal expansion), or a failing valve. Don't cap or plug it. Get it diagnosed promptly.

How old is too old for a water heater?

Federal guidance puts tank heaters at roughly 10 to 15 years and tankless at up to about 20.[1][11] Past that, plan a replacement before it fails.

Can a leaking water heater be repaired?

Leaks from fittings, the drain valve, or the relief valve can often be repaired. A leak from the tank body itself can't; the steel has corroded through.

My pilot light keeps going out. Is the heater dying?

A pilot that won't stay lit is often a thermocouple, a dirty pilot assembly, or a draft problem, all of which are commonly repairable. On an old tank with other symptoms, it may tip the decision toward replacement.

Should my water heater be making any noise?

A gas burner makes a soft whoosh and heat pump units have a fan hum. Loud popping, rumbling, or banging usually means sediment.

What does a tankless error code mean?

Codes are model-specific. Common categories are ignition or flame failure, venting or air-supply problems, overheating, and scale buildup. Check the manual's code table and have a technician diagnose repeat codes.

Can I relight my own pilot?

Many tanks have relighting instructions on the label. Follow them exactly. If the pilot won't stay lit, you smell gas, or you see soot or scorching, stop and call a professional.

Where should a carbon monoxide alarm go?

CPSC recommends UL 2034 alarms on every level and outside sleeping areas, and does not recommend placing them directly above fuel-burning appliances.[4]

How do I tell how old my water heater is?

Read the serial number on the rating plate. Rheem uses month then year,[8] A. O. Smith uses year then week,[9] and Bradford White uses a year letter then a month letter.[10]

How often should the anode rod be checked?

DOE guidance says every three to four years;[6] A. O. Smith recommends once a year.[5]

How often should I flush my water heater?

A. O. Smith says most tanks need flushing at least once a year, more with hard water;[5] EPA WaterSense also suggests yearly.[7]

Keep reading

Tankless in ErieSizing for cold Lake Erie water, gas line and venting.Gas vs electric vs heat pumpWhich fuel fits your home.Cost factorsWhat moves a replacement quote.Service areasErie, Millcreek, Harborcreek, Fairview and more.

Sources

  1. PNNL / DOE Building America Solution Center: Gas-Fired Tankless Water Heaters
  2. Erie Water Works: 2025 Water Quality Report (PDF)
  3. U.S. DOE Technology Fact Sheet: Water Heating (PDF)
  4. U.S. CPSC: Carbon Monoxide Fact Sheet
  5. A. O. Smith: Water Heater Maintenance Guide
  6. U.S. DOE Energy Saver: Storage Water Heaters (archived copy)
  7. U.S. EPA WaterSense: Home Maintenance
  8. Rheem: How to Locate and Read Your Rheem Water Heating Serial Numbers
  9. A. O. Smith: Production date of my device
  10. Bradford White: My Water Heater (determine age)
  11. U.S. DOE Building America: Measure Guideline, Transitioning to a Tankless Water Heater (PDF)
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