If your water heater pilot light is out and you don’t smell gas, you can almost certainly relight it yourself in under 10 minutes. First, take a quick sniff near the unit. Natural gas smells like rotten eggs. No odor? You’re clear to proceed. If you do smell gas, stop immediately, leave the house, and call your gas utility or 911 from outside. Don’t flip any switches or use your phone until you’re clear of the building.

For most homeowners, the fix is straightforward: turn the gas control knob to OFF, wait several minutes, then follow the relight procedure for your specific model. Older units with a standing pilot require a long-reach lighter and a held knob. Newer units with electronic ignition use a button sequence and a status light. Both procedures are covered below, step by step.

Table of Contents

What to check before you touch the water heater

Before you reach for a lighter or press any buttons, run through this short checklist. Skipping it is how small problems become dangerous ones.

Gas smell check: Get low near the water heater and sniff for a sulfur or rotten-egg odor. Natural gas rises, but it also pools near the floor in enclosed spaces. If you detect any gas odor, do not attempt to relight the pilot. Leave the house immediately, leave the door open as you go, and call your gas utility’s emergency line or 911 from a safe distance. Do not operate light switches, garage door openers, or your phone inside the home.

If there’s no gas smell:

  • Turn the gas control knob to the OFF position.
  • Wait at least 5–10 minutes before attempting a relight. This lets any residual gas in the combustion chamber disperse.
  • Gather a long-reach lighter (for manual models) or confirm the unit’s ignitor button is accessible.
  • Open a nearby window or door if the heater is in a closet or garage. Ventilation matters.

Before relighting, always check the label on your water heater. Manufacturers print model-specific instructions directly on the unit. Those instructions override any general guide, including this one. If the label is missing or unreadable, download the manual from the manufacturer’s website using your model number.

Pro Tip: If the heater is in an enclosed utility closet, prop the door open for a few minutes before relighting. If you notice the venting pipe looks disconnected, blocked, or corroded, close the gas valve and call a licensed technician. A blocked flue is not a DIY fix.

How do you relight a standing-pilot water heater?

Older gas water heaters use a continuously burning standing pilot flame. Here’s the correct sequence, aligned with manufacturer relight guidance.

  1. Locate the gas control valve near the bottom of the unit. It typically has three positions: OFF, PILOT, and ON (or a temperature range).
  2. Turn the knob to OFF. Wait a full 5–10 minutes for any residual gas to clear.
  3. Set the knob to PILOT. This position allows a small amount of gas to flow to the pilot tube only.
  4. Depress and hold the knob fully. Pressing it down opens the bypass that keeps gas flowing to the pilot while you light it.
  5. Insert a long-reach lighter through the access opening at the base of the unit and click it near the pilot burner. Keep the knob fully depressed while you do this.
  6. Hold the knob down for 30–60 seconds after the flame catches. This is the critical step most people rush. The thermocouple, a small metal sensor that sits in the pilot flame, needs time to heat up and generate enough voltage to signal the gas valve that the pilot is burning. Release too soon and the gas valve closes, snuffing the flame.
  7. Slowly release the knob. If the flame stays lit, turn the knob to ON (or your desired temperature setting).
  8. Replace the access panel and check the sight glass if your unit has one. You should see a small, steady blue flame.

Visual checks after lighting:

  • The pilot flame should be blue, not yellow or orange.
  • The flame tip should touch the thermocouple rod.
  • Run a hot-water tap for 30–60 seconds to confirm the main burner ignites.

If the pilot goes out the moment you release the knob, or won’t light at all after two careful attempts, stop. Repeated failed attempts point to a thermocouple issue or a gas supply problem that a homeowner shouldn’t troubleshoot further without professional help.

How do you relight an electronic-ignition water heater?

Modern water heaters often skip the standing pilot entirely. Instead, they use an electronic ignition system that sparks on demand, with no continuous flame. The A.O. Smith relight guide explains how these systems use a flame sensor (similar in function to a thermocouple) and can enter a lockout mode to prevent gas buildup if ignition fails repeatedly.

The key difference: instead of holding a lighter to a pilot tube, you’re pressing an ignitor button and reading a status light.

General relight sequence for electronic-ignition units:

  1. Confirm the unit has power (check the circuit breaker if it’s a power-vent or hybrid model).
  2. Verify the gas supply valve on the line feeding the heater is fully open.
  3. Turn the gas control knob to OFF and wait 5 minutes.
  4. Set the knob to PILOT, then press and hold it down.
  5. Press the ignitor button repeatedly (once per second) while holding the knob. Watch through the sight glass for a flame.
  6. Once lit, hold the knob for 30–60 seconds, then release and set to ON.

For units with no standing pilot at all (direct ignition), the control board handles everything. If the unit isn’t producing hot water, the status light is your diagnostic tool. Whirlpool’s support page recommends removing the outer door to view the pilot through the sight glass and consulting the status-light pattern printed on the unit’s label.

Status Light Pattern Likely Meaning Recommended Action
Steady green Normal operation No action needed
1 flash (repeating) Pilot out or not sensed Follow relight sequence
2 flashes (repeating) Thermopile voltage low Check pilot flame position; call pro if persists
4 flashes (repeating) High-temperature limit tripped Let unit cool; call pro if it recurs
No light at all No power or control board fault Check breaker; call pro

Important: Most electronic-ignition units have a built-in lockout after several failed ignition attempts. If the status light shows a lockout code, do not keep pressing the ignitor. Repeated resets can mask a real problem and, in some cases, allow gas to accumulate. Follow the label’s reset procedure once, and call a technician if the lockout returns.

How do you relight an electronic-ignition water heater? — overview diagram

Why does the pilot light keep going out?

A pilot that lights but won’t stay lit is telling you something specific. The cause usually maps directly to what you observe.

Symptom Most Likely Cause DIY or Pro?
Flame dies when you release the knob Failing thermocouple DIY cleaning; pro for replacement
Weak or yellow/orange flame Clogged pilot orifice DIY cleaning (careful); pro if it persists
Pilot blows out repeatedly Draft or venting problem Pro (installation issue)
Pilot won’t light at all Gas supply off or orifice blocked Check supply valve; pro if blocked
Electronic ignition won’t spark Faulty ignitor or control board Pro

Water heater pilot flame and thermocouple sensor

Common root causes include a failing thermocouple, a dirty pilot orifice, drafts, improper gas pressure, and a failing gas control valve. Repeated outages almost always point to a part failure rather than a one-time fluke.

The thermocouple is the most common culprit. Its only job is to generate a small electrical signal when heated by the pilot flame. As it ages, that signal weakens. The gas valve reads a weak signal as “no pilot” and shuts off gas flow. A pilot that dies the moment you release the knob is the classic thermocouple failure sign.

Practical checks worth doing yourself:

  • Hold the knob down for a full 60 seconds (not 30) on your next attempt. Underheating the thermocouple is the most common DIY mistake.
  • Look at the flame color. Blue means clean combustion. Yellow or orange means incomplete combustion, often from a partially blocked orifice.
  • Check for drafts. An open garage door, a nearby HVAC vent, or a gap in the flue can blow out a pilot repeatedly. Close doors and retest.
  • Confirm the gas supply valve on the line to the heater is fully open (handle parallel to the pipe).
  • Check whether other gas appliances in the home are working. If the stove also has no gas, the issue is upstream.

Stop DIY troubleshooting and call a pro if:

  • You smell gas at any point.
  • The pilot fails after two careful, correctly timed attempts.
  • The flame is yellow, orange, or producing visible soot.
  • An electronic ignition code reappears after a reset.
  • The unit is more than 10–12 years old and has had multiple recent outages.

What tools and costs should you expect?

Relighting a pilot costs nothing beyond a few minutes and a long-reach lighter. Light troubleshooting adds a few inexpensive items. Actual part replacements are where costs climb.

Tools for relighting and basic inspection:

  • Long-reach lighter or fireplace matches
  • Flashlight (to see the pilot assembly clearly)
  • Protective gloves
  • Small wire brush or fine sandpaper (for cleaning thermocouple tip)
  • Adjustable wrench (if you’re replacing a thermocouple yourself)

Cost and time comparison:

Task DIY Cost Pro Cost (Installed) Typical Time
Relight pilot a few dollars (lighter) N/A 5–15 minutes
Thermocouple replacement $10–$25 (part only) $150–$250 installed 15–45 minutes
Pilot assembly cleaning minimal cost (DIY tools) approximately $100 (service call) 30–60 minutes
Gas control valve replacement Not recommended DIY several hundred dollars installed 1–2 hours
Full unit replacement Varies $900–$2,500+ installed Half to full day

Thermocouple replacement is a job many confident DIYers handle: the part is cheap, the access is usually straightforward, and the procedure is well-documented. Gas valve replacement is a different matter. The valve controls all gas flow to the unit, and an improper installation creates a genuine safety hazard. That one belongs with a licensed technician.

For water heater troubleshooting beyond a basic relight, the cost of a professional diagnosis often pays for itself by correctly identifying the problem the first time.

When should you stop and call a licensed technician?

Some situations are simply not safe for a homeowner to handle, regardless of how handy you are.

Call a licensed plumber or HVAC technician immediately if:

  • You smell gas anywhere near the unit, even faintly.
  • The pilot won’t stay lit after two properly executed attempts.
  • The pilot keeps going out repeatedly over days or weeks.
  • The flame is yellow, orange, or producing black soot on the unit.
  • An electronic ignition fault code reappears after a reset.
  • You see a damaged, corroded, or disconnected gas line.
  • The gas control valve feels loose, damaged, or won’t turn properly.

Why licensing matters here: Gas valve replacements and control board repairs involve the gas supply line directly. In most U.S. jurisdictions, this work requires a licensed plumber or gas fitter. Improper work can void your water heater’s warranty, fail a home inspection, and create a carbon monoxide or explosion risk. A licensed technician carries liability insurance and pulls permits where required.

Before you call, have this information ready:

  • Water heater brand and model number (on the label near the gas valve)
  • Age of the unit (installation date, if known)
  • What you observed: flame color, how long it stayed lit, any error codes
  • Number of relight attempts you made
  • Whether other gas appliances in the home are working normally

Key Takeaways

A water heater pilot light that’s out is usually a safe, fixable problem at home, but a pilot that won’t stay lit after correct relighting almost always signals a failing thermocouple, clogged orifice, draft issue, or gas control valve failure that needs professional attention.

Point Details
Gas smell means evacuate Leave immediately and call your gas utility or 911 from outside; never attempt a relight.
Standard relight sequence OFF → wait 5–10 min → PILOT → hold knob 30–60 sec → ON; follow your unit’s label.
Pilot won’t hold after release A thermocouple failing to generate voltage is the most common cause; clean or replace it.
Electronic ignition lockouts Read the status light pattern and follow the label reset once; repeated lockouts need a pro.
Empire Plumbing and Air Conditioning Licensed Phoenix-area technicians available 24/7 for water heater repair when DIY steps don’t resolve the issue.

The part most homeowners get wrong

Most pilot-light guides focus on the relight sequence, and that’s fine. But the real mistake homeowners make is treating a recurring outage as a relighting problem rather than a parts problem.

A pilot that goes out once after a power flicker or a brief gas interruption is a nuisance. A pilot that goes out every few days is a thermocouple that’s been failing for months. The two situations look identical from the outside, but they have completely different solutions. Relighting a failing thermocouple over and over doesn’t fix anything. It just delays the repair and, in some cases, trains homeowners to ignore a warning sign that’s getting worse.

The other thing guides underplay is the draft issue. In Phoenix, garage-mounted water heaters are common, and garage doors opening and closing create real airflow disruptions. A pilot that blows out every time the garage door opens isn’t a thermocouple problem. It’s a venting or installation problem, and no amount of relighting will change that.

The honest answer is this: one failed relight attempt is normal. Two failed attempts with the correct technique means something in the system needs attention. Calling a technician at that point isn’t admitting defeat. It’s the faster, safer path to hot water.

Empire Plumbing and Air Conditioning handles what the relight guide can’t

When the pilot won’t hold, the status light keeps flashing, or you’d rather not deal with gas lines yourself, Empire Plumbing and Air Conditioning is the call to make. The company has served Phoenix, Scottsdale, Glendale, Mesa, Tempe, Gilbert, Peoria, Anthem, and surrounding communities for over 25 years, with licensed technicians (ROC 342717 & 342718) who handle water heater diagnostics, thermocouple replacement, gas valve service, and full unit installation.

Empire Plumbing and Air Conditioning

Same-day and 24/7 emergency service means you’re not waiting a week for hot water when the problem turns out to be more than a simple relight. Transparent pricing and no-surprise billing are standard. Whether the fix is a $25 thermocouple or a full water heater repair in Phoenix, the technician will tell you exactly what’s needed before any work begins. Call or book online when your pilot situation matches any of the red flags in this guide.

Useful sources and further reading

Do not wait for a small AC issue to become a major breakdown. If your air conditioner is blowing warm air, making strange noises, leaking water, or failing to cool your home, Empire Plumbing & Air Conditioning can help.

Call 602-275-8400 today to schedule professional Plumbing repair in North Phoenix, AZ.

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