If your pilot wont stay lit, your water heater can’t heat reliably—and repeated relighting attempts can become a safety risk if something is wrong with gas supply or venting. However, you can run a few safe, homeowner-friendly checks to narrow down the cause before you call a pro.
This guide is for homeowners in Gaithersburg (20878) and nearby Montgomery County areas including Rockville, Germantown, North Potomac, Darnestown, Montgomery Village, Potomac (north), Derwood, Kentlands, and Washington Grove.
Pilot wont stay lit: safety rules first
Before anything else, follow these rules:
- If you smell gas, stop immediately. Leave the area and contact your gas utility or emergency services.
- Don’t keep relighting the pilot repeatedly. If something is failing, repeated attempts can make the situation worse.
- Keep the area ventilated and keep flames/sparks away.
- For general gas-appliance safety, the CPSC has guidance here: https://www.cpsc.gov/Safety-Education/Safety-Guides/Home/Gas-Appliances
If you want this handled safely and correctly, our team can help through Water Heater Services.
Pilot wont stay lit: quick diagnosis in 60 seconds
First, answer these questions:
- Does the pilot go out immediately, or after the burner runs for a while?
- Immediately: often a thermocouple/flame sensor, pilot assembly, or gas control issue.
- After heating: often ventilation/overheating, dirty burner, or safety shutdown behavior.
- Do you see error lights (for units with status indicators)?
- Yes: the blinking pattern can point to a specific lockout.
- No: you’ll rely more on symptoms and basic checks.
- Did this start after a cold snap, wind, or recent work?
- Yes: venting/draft problems become more likely.
Next, use the sections below to pinpoint the most common causes.
Pilot wont stay lit: the 7 most common causes
1) Pilot wont stay lit because the thermocouple is weak or failing
On many gas water heaters, the thermocouple sits in the pilot flame and confirms the flame is present. If it doesn’t detect heat properly, it shuts gas off for safety.
Common clues
- Pilot lights, but goes out when you release the control knob
- Pilot stays briefly, then drops out unpredictably
What to do
- This typically needs service. Therefore, schedule Water Heater Services.
2) Pilot wont stay lit because the pilot assembly is dirty
Dust, lint, or debris can interfere with the pilot flame.
Common clues
- Weak pilot flame (small, yellow, or flickering)
- Pilot lights, but struggles to stay stable
What to do
- A technician can clean and tune safely. Additionally, they’ll verify combustion quality.
3) Pilot wont stay lit because of a draft or venting problem
A backdraft or improper venting can disrupt the flame or trigger safety shutdown.
Common clues
- Pilot goes out more often on windy days
- You notice soot, scorching, or unusual odors near the draft hood
- The unit seems “touchy” during burner operation
What to do
- Call a pro. Meanwhile, don’t run the heater if you suspect venting issues.
4) Pilot wont stay lit because the gas control valve is failing
Gas control valves can fail with age, heat cycling, or internal wear.
Common clues
- Pilot won’t hold even after repeated correct lighting steps
- Burner behavior seems inconsistent
- The unit locks out unexpectedly
What to do
- A pro should test and confirm. If replacement makes sense, we handle it under Water Heater Services.
5) Pilot wont stay lit due to low gas supply or gas pressure issues
If gas supply is inconsistent, the pilot can drop out.
Common clues
- Other gas appliances also act “weak” or inconsistent
- Pilot flame looks unusually small
What to do
- Contact your gas utility if you suspect supply problems. Also, schedule service for the heater.
6) Pilot wont stay lit because of combustion air problems
A water heater needs adequate combustion air. In tight utility rooms or closets, it may starve for air and shut down.
Common clues
- The heater works better with the door open (do not rely on this as a “solution”)
- Pilot issues started after remodeling, sealing, or adding doors/insulation
What to do
- A pro can confirm code-safe combustion air solutions.
7) Pilot wont stay lit because the unit is near end-of-life
When a heater is older, multiple small issues add up.
Common clues
- Repeated failures (pilot, burner, temperature swings)
- Rust, moisture, or corrosion near the base
- Declining hot water performance
What to do
- At this point, replacement may be smarter than repeated repairs. We can evaluate options via Water Heater Services.
Pilot wont stay lit: safe checks you can do at home
These checks are safe and helpful. However, avoid disassembly unless you’re trained.
Check 1: Confirm you’re lighting it exactly as the label says
First, read the lighting instructions on your heater (they vary). Next, follow timing carefully—many systems require you to hold the knob down long enough to heat the thermocouple.
Check 2: Look at the pilot flame appearance (without removing parts)
If you can see the pilot flame safely:
- A healthy flame is usually steady and mostly blue.
- A weak, yellow, or flickering flame can indicate dirt or airflow issues.
Check 3: Check the area for drafts
For example, if the heater sits near a door to the outside, a leaky basement window, or a strong exhaust fan, a draft can destabilize the pilot.
Check 4: Note any “shutdown pattern”
If the pilot fails only when the burner runs, that pattern often points to venting, overheating, or combustion issues. Therefore, it’s valuable info for your plumber.
For general water-heating efficiency and system basics, DOE has a helpful overview: https://www.energy.gov/energysaver/water-heating
Pilot wont stay lit: what NOT to do
When pilot wont stay lit, avoid these risky moves:
- Don’t keep relighting it all day. Repeated resets can mask a real hazard.
- Don’t modify safety components or bypass switches.
- Don’t use chemical sprays near the burner or pilot area.
- Don’t ignore venting concerns if you smell unusual odors or see soot.
Pilot wont stay lit: when to call a plumber
Call a plumber immediately if:
- The pilot goes out repeatedly after correct lighting steps
- You see soot, scorching, or suspect venting problems
- The heater is in a tight closet and seems air-starved
- The unit is older and failures are becoming frequent
- You want a safe repair vs replace decision
Start here: Water Heater Services.
If you also notice pressure-related issues or supply leaks near the heater area, we can coordinate diagnosis via Water Line Repair as needed.
Service Area (Maryland only)
Quince Orchard Plumbing serves Gaithersburg (20878), Rockville, Germantown, North Potomac, Darnestown, Montgomery Village, Potomac (north), Derwood, Kentlands, and Washington Grove.
CTA
If your pilot wont stay lit, call Quince Orchard Plumbing for safe, local diagnosis and Water Heater Services in Montgomery County, MD.