Water Heater Not Working? 9 Checks Before You Call

If your water turns cold mid-shower or your heater goes silent, you need answers fast. Here’s a clear, safe path to check the basics and avoid risky mistakes.

At Billy Rogers Plumbing, we handle emergency plumbing day and night. This guide gives you simple steps, what to watch for, and when to stop and call in a licensed tech. If anything feels unsafe at any point, pause and get help.

Problem/Scenario: No Hot Water or Inconsistent Hot Water

No hot water can come from several causes—tripped power, gas supply issues, failed thermostats or elements, a clogged vent, or sediment buildup. Before you assume the worst, run through the safe checks below. Many fixes are quick. Others need a pro with the right tools and training.

If you smell gas, hear sparking, or see water leaking onto floors, treat it as urgent and get help right away.

Quick Safety Checklist ✅

• Turn off power before opening any electric water heater panel. Use the breaker, not just the local switch. (OSHA lockout/tagout principles apply at home—ensure power is truly off.)
• For gas units, turn the gas control to OFF if you suspect a leak. If you smell gas, leave the area and call your gas utility or 911.
• Water at 120°F is recommended by the U.S. Department of Energy for comfort and safety. Higher settings increase scald risk.
• The temperature and pressure (T&P) relief valve is a safety device. Do not cap or block it. If it discharges constantly, that’s a stop-and-call situation.
• If you’re not sure about a step, don’t guess. Call Billy Rogers Plumbing for Emergency Plumbing near you.

Identify Your Unit 🧰

Knowing what you have helps you troubleshoot the right way.

• Tank vs. tankless:
  • Tank: Large cylinder, insulated jacket, hot and cold pipes on top, a T&P valve on the side or top.
  • Tankless: Compact wall unit with intake/exhaust vent, often digital display, continuous flow.
• Fuel type:
  • Electric: No flue/vent pipe. Has electrical conduit or cord and removable access panels.
  • Gas: Has a vent or exhaust pipe. Look for a gas control valve and burner/pilot access.
• Age and model tag:
  • Find the data plate: usually on the side of a tank or the bottom/front of a tankless unit.
  • Note brand (A. O. Smith, Rheem, Bradford White, Rinnai, Navien, etc.), model, serial (age is coded), BTU or wattage, and capacity (gallons or GPM).

Pro tip: Most residential tanks last about 8–12 years; tankless units can go 15–20 with maintenance.

Electric Checklist (9 Steps) ⚡

Always switch the water heater breaker OFF before removing any panels.

1. Check the breaker or fuse

• Look for a tripped breaker. Reset once. If it trips again, stop and call a pro—repeated trips point to a shorted element, wiring fault, or thermostat issue.

1. Press the high-limit reset button

• Remove the upper access panel and insulation carefully. Press the red reset button on the upper thermostat. If it clicks, restore power and wait 30–60 minutes. If it trips again, you likely have a thermostat or element problem.

1. Verify thermostat settings

• Typical settings are near 120°F. If one thermostat is set far lower than the other, you may get lukewarm water. Set both upper and lower thermostats consistently.

1. Inspect wiring connections (power OFF)

• Look for melted insulation, burnt connectors, or loose screws at thermostats and elements. Damaged wires require a licensed repair.

1. Listen and feel for heating

• After restoring power briefly, you may hear a gentle hum or feel warmth at the tank sides after 20–30 minutes. If nothing changes, power back OFF and continue checks.

1. Check for sediment clues

• Popping or rumbling sounds signal sediment over the lower element. Long recovery times can also point to sediment. A flush can help, but a heavily scaled tank may need element replacement.

1. Test heating elements (multimeter)

• With power OFF and wires removed from the element, measure resistance: a typical 4500W element is around 10–12 ohms. Infinite resistance means it’s open (failed). A short to ground is also a fail. If you don’t have a meter, this is a job for a tech.

1. Inspect the T&P valve and drain

• Drips from the T&P discharge may indicate overheating or high pressure. If it won’t stop, shut off power and cold water supply, then call for service.

1. Check for leaks at elements and gaskets

• Moisture around the element access or at the bottom of the tank can indicate a gasket leak or tank failure. Slow leaks can cause electrical hazards—don’t delay repairs.

Safety reminder: Replace covers and insulation before restoring power. Never power the unit with panels off.

Gas Checklist (9 Steps) 🔥

If you smell gas at any time, leave the area and call your gas utility or 911. Do not operate switches or create sparks.

1. Confirm gas shutoff is on

• The gas valve handle should be parallel to the pipe (ON). If it’s perpendicular, it’s OFF.

1. Identify ignition type

• Standing pilot: Has a small flame visible at all times (through a viewing window).
• Electronic ignition: No standing flame; the unit sparks or glows to light the burner.

1. Check the pilot (standing pilot models)

• If the pilot is out, follow the lighting instructions on the label. If it won’t stay lit, the thermocouple may be faulty or you may have draft issues.

1. Look at the control status (electronic)

• Many modern gas heaters have status lights or error codes. Note the blinking pattern and model number for the technician.

1. Verify the thermostat/dial setting

• Set to 120°F or “Hot.” Too low and you’ll get lukewarm water. Avoid scald risks with higher settings.

1. Inspect venting and air supply

• Ensure the vent is connected, not crushed, and sloped upward on standard-efficiency units. For high-efficiency (condensing) units, check PVC intake/exhaust for obstructions. Poor venting can cause unsafe combustion.

1. Check flame color

• A healthy burner flame is mostly blue with small yellow tips. Large lazy yellow flames can mean poor combustion—turn the unit OFF and call a pro.

1. Condensate and drain (high-efficiency)

• Condensing units make water that drains via a trap/hose. If the trap is blocked, the heater may lock out. Clear visible kinks and ensure the line slopes to a drain.

1. Look for water leaks and T&P discharge

• Leaks at the drain valve or from the tank body suggest service is needed. Continuous T&P discharge means over-temperature or pressure issues—turn to OFF and call.

Safety reminder: The National Fuel Gas Code (NFPA 54) and manufacturer instructions must be followed for gas work. If you’re unsure, stop and get help.

Common Symptoms and Likely Causes 🧩

• No hot water at all
  • Electric: Tripped breaker, high-limit tripped, failed upper thermostat or upper heating element.
  • Gas: No gas supply, pilot out, ignition fault, gas valve failure.
• Lukewarm only or runs out fast
  • One element down (electric), thermostat mis-set, sediment covering lower element, dip tube failure in older tanks, undersized tank or too many simultaneous fixtures.
• Hot for seconds, then cold (tankless “cold water sandwich”)
  • Normal brief effect on some tankless models, clogged inlet screen, scale on heat exchanger, minimum flow not met, recirculation timing issues.
• Water takes too long to reheat
  • Sediment buildup, failed lower element (electric), partially closed cold supply valve, thermostat set too low, gas input too small for demand.
• Rumbling, popping, or hissing
  • Sediment boiling on the element or tank bottom, scale on heat exchanger (tankless), or air in lines after service.
• Discolored or smelly water
  • Brown/rusty: anode rod depleted or tank corrosion. Rotten egg smell: certain water chemistry reacting with the anode. Consider anode replacement or water treatment.
• T&P valve drips or discharges
  • Excess temperature or pressure, failed valve, closed expansion tank or no expansion control. Do not cap a T&P. Shut power/gas and call for service.
• Leaks at the base
  • Could be drain valve, element gasket, or the tank itself. If the inner tank has split, replacement is the safe fix.

Authoritative references: U.S. Department of Energy (water heating guidance), NFPA 54 (gas safety), International Residential Code and Uniform Plumbing Code (installation and safety), and manufacturer manuals (A. O. Smith, Rheem, Bradford White, Rinnai, Navien).

Repair vs. Replace Signals 🔄

• Age
  • Tank: 8–12 years is the typical service life. Past this, a major part failure often points to replacement.
  • Tankless: 15–20 years with regular maintenance.
• Repeated repairs
  • If you’ve replaced elements, thermostats, or gas parts more than once in a short time, the tank or heat exchanger may be near the end.
• Efficiency gains
  • Newer units can reduce energy use (DOE notes water heating is a home’s second-highest energy load). Upgrading to a high-efficiency gas or heat pump water heater can cut bills.
• Visible tank leaks or rust
  • Inner tank corrosion is not repairable. Replace promptly to avoid water damage.
• Capacity mismatch
  • Family changes or new fixtures may require a larger tank or a properly sized tankless.

Regional Nuance 🌎

• Hard water areas
  • Scale builds fast. Flush tanks annually and consider anode inspections every 2–3 years. Tankless units may need descaling every 6–12 months depending on grains per gallon. Water filtration or softening can protect heaters and fixtures.
• Seismic zones
  • Strap tanks to wall studs at the upper and lower thirds, and use rigid gas connectors or seismic valves as required by local code.
• Cold climates
  • Protect tankless intake/exhaust and condensate drains from freezing. Insulate exposed hot and cold pipes and the T&P discharge line per code.
• High altitude
  • Gas units may need altitude-specific orifices and derating adjustments. Follow the manufacturer’s installation manual.

DIY vs. Call a Pro 🧠

DIY-friendly:

• Resetting a breaker or high-limit button
• Adjusting thermostat settings
• Cleaning a tankless inlet screen
• Basic tank flush (if valves and drain work properly)

Call a licensed plumber:

• Replacing heating elements, thermostats, anode rods, or gas valves
• Diagnosing electrical shorts or repeated breaker trips
• Gas ignition faults, pilot issues that persist, venting problems
• Persistent T&P discharge, expansion tank problems, or any leak at the tank seam
• Repiping, gas line installation, or code-required upgrades (expansion control, seismic strapping, proper venting, drain pans)

At Billy Rogers Plumbing, we use OEM parts, follow IRC/UPC and NFPA 54 requirements, and provide documentation for your records.

What Pros Do On Arrival 🧰

• Safety first
  • Verify no gas leaks, confirm electrical isolation, and assess T&P/expansion control.
• Diagnostic testing
  • Electrical: continuity and insulation tests on elements, thermostat function, load checks.
  • Gas: combustion air check, draft test, ignition sequence review, CO readings where applicable.
• Mechanical inspection
  • Sediment assessment, anode condition, drain valve function, leak tracing with moisture meters.
• Code compliance review
  • Vent clearances, drain pan, seismic strapping, discharge piping, vacuum breaker/anti-siphon where required.
• Clear options
  • Repair vs. replace paths with pros/cons, expected service life, and efficiency impacts.

Prevention & Maintenance 🛠️

• Annual tank flush
  • Reduces sediment and improves recovery time. In very hard water, consider every 6 months.
• Anode rod checks
  • Inspect every 2–3 years; sooner with smelly water or aggressive water chemistry.
• Temperature setting
  • 120°F is a good balance of comfort, energy savings, and scald protection (DOE guidance).
• Expansion control
  • In closed systems, a properly sized expansion tank protects the T&P valve and the heater.
• Tankless care
  • Clean inlet screen, descale heat exchanger as needed, and keep intake/exhaust clear.
• Catch leaks early
  • Use a drain pan with a plumbed drain when possible. Consider a leak sensor with a shutoff valve for added protection.
• Keep clearances
  • Maintain service space per manufacturer instructions. Don’t store flammables near gas units.

Costs & Time Factors (Ranges, Not Quotes) 💸

Every home is different, but here are general ranges that influence cost and timing:

• Electric heating element replacement
  • Often 1–2 hours plus parts; add time if sediment is heavy or shutoffs are corroded.
• Thermostat or high-limit replacement
  • 1–2 hours; may pair with element testing.
• Anode rod replacement
  • 1–2 hours; more if clearance is tight or rods are seized.
• Tank flush and tune-up
  • 45–90 minutes, depending on sediment level and valve condition.
• Gas valve or thermocouple/igniter work
  • 1–3 hours; add time for vent or combustion air corrections.
• Tank replacement
  • Half-day in straightforward cases; longer if adding expansion control, seismic straps, new venting, drain pan, or permit steps.
• Tankless replacement or installation
  • Varies widely with gas sizing, vent routing, condensate, and recirculation. Plan for a full day or more in complex retrofits.

Permits and inspections may be required. We perform code-compliant work and coordinate as needed.

When It’s an Emergency 🚨

Call immediately if you have:

• Active leaks, especially hot water spraying or pooling near electrical parts
• Continuous T&P valve discharge
• Gas smell or suspected carbon monoxide issues (leave and call your utility/911 first)
• No hot water with vulnerable occupants (infants, elderly, medical needs)
• Scalding-hot water or temperature spikes after normal use

We offer emergency plumbing service 24/7. If you need Emergency Plumbing near you right now, we’re ready to help.

Electric Checklist (9 Steps) — Quick Recap

• Breaker/fuse
• High-limit reset
• Thermostat settings
• Wiring inspection (power OFF)
• Heating response
• Sediment signs
• Element test with meter
• T&P behavior
• Gasket and base leaks

Gas Checklist (9 Steps) — Quick Recap

• Gas shutoff on
• Pilot type identified
• Pilot lit (if standing pilot)
• Electronic status codes
• Thermostat/dial setting
• Venting and air supply
• Blue flame color
• Condensate drain clear
• No leaks/T&P issues

Local/Seasonal Considerations 🌤️

• Spring: Good time for a full flush and anode inspection after heavy winter demand.
• Summer: Vacation mode on some models can save energy; ensure recovery time suits guests.
• Fall: Prep for cold snaps—insulate pipes, check tankless freeze protection, test expansion tank.
• Winter: Prevent frozen vents or condensate lines; maintain adequate combustion air.

FAQ 💬

Q: Why does my electric heater’s reset button keep tripping?
A: Usually overheating from a failed thermostat, stuck relay, or a shorted heating element. Turn power OFF and call a pro.

Q: How often should I flush my water heater?
A: Once a year for most homes. In hard water areas, every 6 months. Tankless units may need descaling every 6–12 months.

Q: What temperature should I set?
A: 120°F is common per DOE guidance. If you need hotter water for sanitation, consider a mixing valve to reduce scald risk at fixtures.

Q: Can a tankless water heater freeze?
A: Yes. Many have built-in freeze protection, but exterior units still need proper insulation and power for heaters to run. Protect condensate lines from freezing.

Trust, Licensing, and How We Work 🧾

• Licensed and insured plumbers who follow local code, the International Residential Code/Uniform Plumbing Code, and NFPA 54 for gas work
• OEM replacement parts that match your model
• Clear diagnostics, written options, and manufacturer-aligned procedures
• Respect for your home: drop cloths, clean work areas, and disposal of old parts/equipment

Final Thoughts

Use the checklists here to rule out simple causes. If a step feels unsafe or the problem persists, stop and call. Fast, code-compliant repairs protect your home, your budget, and your hot water supply.

Call Billy Rogers Plumbing now — or reach us anytime at  1-877-478-7794 .