Natural gas itself is odorless. PG&E and other utilities add mercaptan, a chemical that smells like rotten eggs or strong sulfur, as a deliberate warning system. If you smell that rotten-egg odor anywhere in your home - treat it as an emergency until proven otherwise.
What NOT to Do If You Smell Gas
DO NOT flip any light switches or unplug appliances
Even a wall switch creates a micro-spark inside the contacts. That spark can ignite gas at 5–15% air concentration.
DO NOT use your cell phone inside the building
Cell phones can spark. Walk outside first, then call. The 30-second walk could save your life.
DO NOT light matches, candles, or use lighters
Open flames ignite natural gas instantly at the right concentration.
DO NOT try to find the leak source yourself
Leave this to PG&E and licensed technicians with electronic leak detectors. Evacuate, then call.
DO NOT re-enter the building until cleared by authorities
Wait for PG&E or fire department clearance. Gas concentrations can fluctuate; the room can re-fill in minutes if the source is still leaking.
Common Causes of Gas Smell From a Stove
Not every gas smell is the same severity. After PG&E clears the building, a licensed range and oven technician diagnoses the cause and performs the repair. Common sources we find on SF Bay Area service calls:
Pilot Light Extinguished (older stoves)
Pre-1990 gas stoves often have standing pilot lights that can blow out from a draft. Releases small amounts of gas until relit. If the smell persists after relight, evacuate.
Loose or Worn Gas Flex Line Connection
The flexible line connecting your range to the wall valve loosens over time, especially if the stove gets pulled out for cleaning. Most common cause in SF rental and short-term-let kitchens.
Failed Gas Valve, Shutoff, or Regulator
Control valves on the stove wear out and start leaking gas even when burners are off. This is more serious than a flex-line issue and requires full valve replacement.
Burner Igniter Failing or Slow
If a burner takes more than 2–3 seconds to ignite, unburned gas escapes during the delay. Not an immediate emergency if the burner eventually lights, but the igniter or spark module needs service.
Damaged Flex Line From Moving the Stove
Pulling the stove out repeatedly to clean behind it can kink or crack the gas flex line. In SF flats with tight kitchen layouts this is a recurring issue.
Corroded Threaded Connection (older homes)
Pre-1960 SF, Daly City, and Marin homes often have threaded gas connections that corrode over decades. Replacing the connection with a new flex line and approved tape is a licensed-tech job.
Andrei's Field Note
"A Pacific Heights family called me after PG&E had been to their home twice in two months - both times PG&E tagged the range as the gas leak source but could not pinpoint the connection. The stove was a 12-year-old Wolf DF366. When I pulled it out from the wall the flex line looked visually fine - no kinks, no cracks, no corrosion. But when I soaped the connection threads at the back of the stove, I could see slow bubbles forming on one fitting. The previous tech who installed the stove had used PTFE tape on the gas line threads - which is forbidden on gas connections. The correct material is yellow PTFE-coated gas tape or pipe dope rated for gas. I replaced the flex line, used proper gas-rated tape, soap-tested the connections, and the leak was gone. Total bill $185. The lesson: even a licensed installer can make a small material mistake. After every gas appliance install, request a soap test on every connection."
— Andrei, Lead Appliance Technician, FixitBay LLC · CA License #51001 BHGS
How to Prevent Gas Leaks From Your Stove
- Annual professional inspection - licensed CA technician checks all connections, valves, igniters.
- Replace flex line every 10–15 years - even if visually fine. CSA-rated stainless flex line.
- Do not move the stove yourself - call a tech to disconnect/reconnect the gas line for cleaning.
- Test burner ignition - if it takes more than 2–3 seconds, schedule service.
- Install a natural gas detector - place near the kitchen ceiling (natural gas is lighter than air).
- Post-earthquake inspection - after any M4.0+ Bay Area earthquake, soap-test all gas connections.
When to Call a Professional
After PG&E or the fire department clears your home as safe, you need a licensed appliance technician (not a generic handyman) to:
- Inspect all gas connections, valves, and lines.
- Test for leaks using electronic detection equipment and soap test.
- Repair or replace faulty valves, regulators, or igniters.
- Re-tighten or replace gas flex lines with proper gas-rated tape/dope.
- Provide a written safety clearance for your records.
Never attempt DIY gas line repairs. In California, this work must be performed by a licensed technician. Improper repairs void homeowner insurance and can kill people.
FixitBay LLC provides gas stove repair across the Bay Area - igniters, burner valves, and gas connections. For local availability and neighborhood coverage, see our San Francisco appliance repair page.
| Service | Cost | Notes |
|---|---|---|
| PG&E emergency dispatch | $0 (free, 24/7) | Shut off & tag only |
| Licensed appliance diagnostic | $80 (credited toward repair) | Required after PG&E tag |
| Gas flex line replacement | $140 – $240 | CSA-rated stainless line |
| Shutoff valve replacement | $180 – $320 | Behind wall, parts + labor |
| Burner igniter replacement | $120 – $220 | Per burner |
| Full safety inspection with leak certificate | $160 – $260 | Annual recommended |
| Gas regulator service / replacement | $220 – $380 | Licensed-tech only |
Gas Smell Safety - Common Questions
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BHGS-licensed CA Major Appliance Technician (License #51001) - leak detection, flex line replacement, igniter service across SF, Marin, and the Peninsula. Annual inspection recommended.
