Read the first section first
Gas Line Repair Denver
Gas Leaks, Appliance Lines & Sediment Traps
Start here. If you smell gas right now, stop reading, get everyone out of the house, and call 911 or your gas utility from outside. Everything else on this page is written for a calm day, when nothing smells wrong and you want to understand the system.
- Evacuate first, call outside
- Never hunt a leak
- Connectors, valves, sediment traps
- Altitude changes gas appliances
If you smell gas, leave. Then call.
Do it in this order, and do it before you talk yourself out of it. Get every person and pet out of the building. Leave the door open behind you. Touch nothing electrical on the way out: not a light switch, not the thermostat, not the garage door opener, not your phone. No lighters, no matches, no starting a car in an attached garage. Walk down the street, well away from the house, and call 911 or your gas utility's emergency line from there. Utilities treat a reported odor as an emergency, come day or night, and don't charge you for being wrong.
Now the things not to do, because these are the ones that hurt people. Don't go looking for the source. Don't spray soap on fittings to hunt it down. Don't open windows and wait to see if it clears. Don't flip on a fan to ventilate. Don't close the meter valve unless you're already outside, you have the wrench, and you know which valve it is. And if a carbon monoxide alarm is sounding, or anyone is dizzy, nauseous, or unusually sleepy, that's a 911 call from outside, immediately, no discussion.
The plumber comes second in this sequence, always. The utility responds, confirms the leak, shuts the gas at the meter and locks it. A licensed gas fitter makes the repair and pressure tests the system. Only after it passes does the utility restore service and relight the appliances. Nobody skips a link in that chain, including you.
The whole protocol fits in one line: out of the house, down the street, phone call from there. Every minute you spend confirming the smell, finding the source, or looking up a plumber is a minute spent inside a building filling with fuel. Get out first. Sort out who fixes it once you're standing on the sidewalk.
Where residential gas lines actually fail
Appliance connectors lead the list. The flexible connector behind a range or dryer kinks a little more every time somebody pulls the appliance out to clean, and metal flexed enough times cracks at the bend. Old uncoated brass connectors from the 1960s and 70s are worse: they fail at the flare fitting, they're considered obsolete, and any still in service should be replaced the next time a technician is standing there.
Threaded black iron is the backbone of most older systems, and it fails at the joints. Pipe dope dries and shrinks over decades. Furnace vibration works a fitting loose. Steel corrodes where it passes through concrete, sits on a damp crawlspace floor, or runs along a garage wall that takes driven snow all winter. Exterior lines out to a grill, fire pit, or detached shop are their own category, since buried steel and a landscaping project are natural enemies.
Newer homes fail differently. The yellow flexible tubing called CSST is thin-walled by design, quick to install and easy to puncture with a drywall screw or a picture nail. It also has bonding requirements that a qualified installer knows and a weekend project does not. Then there are valves: an appliance shutoff weeping at the stem, or a missing sediment trap that lets debris reach a gas valve never built to handle it.
| What you notice | What it usually means | What you do |
|---|---|---|
| Rotten egg smell, any strength | A live leak until proven otherwise | Everyone outside now, call from down the street |
| Hissing near a line, meter, or appliance | A larger leak and a shorter clock | Same answer, and do not go looking for it |
| A carbon monoxide alarm sounding | Incomplete combustion somewhere in the house | Outside first, then 911. Never reset and wait |
| Dead grass in a line across the yard | Possibly a buried line leaking underground | Stay off it, call the utility, nobody digs |
| Yellow lazy flames or soot on a burner | Combustion trouble, often altitude or airflow | Stop using that appliance and book a service call |
Why this one is never a DIY line, and what it runs
A real gas repair has steps a hardware store trip can't cover. The section gets isolated. Black iron gets cut, threaded, and reassembled with gas-rated sealant, because the white tape next to it on the shelf is for water. Then the system gets pressurized and held on a gauge to prove it's tight, and only then does the meter go back into service and every appliance get relit and checked. Skipping the test is how a repaired leak becomes a leak nobody knows about.
Along the Front Range, replacing a single appliance connector or a bad shutoff valve commonly lands in the low hundreds. Running a new line to a range, dryer, grill, or garage heater typically runs a few hundred to a couple thousand, driven by distance, finished surfaces, and whether any of it goes underground. Leak repair on aging black iron climbs past that, because pressurizing an old system tends to reveal the second and third joint on their way out.
Altitude earns its own paragraph, because this corridor spans a lot of it. Homes run from about 4,970 feet in Firestone to 6,961 feet in Monument, and thinner air means less oxygen per cubic foot for a burner. Appliances have to be set up for the altitude they sit at, and a unit shipped from a sea-level warehouse often isn't. Yellow flames, soot, and a water heater that never quite recovers can trace back to that rather than to a leak, which is the same conversation as our water heater guidance.
Need this handled this week?
Start a quoteThe ten-minute audit for a calm day
None of this applies if you smell gas. That's the other page, the one at the top. On an ordinary Saturday, spend ten minutes learning your own system. Find the main gas valve at the meter and notice it takes a wrench, not a hand. Buy one and hang it there. The valve is closed when the tang sits crosswise to the pipe. And understand the rule that goes with it: once that valve is closed, you don't reopen it. The utility does, and they relight everything.
Then walk the house and take notes rather than actions. Every appliance should have its own shutoff within reach of it. Your furnace and water heater should each have a sediment trap, the short capped stub pointing down near the gas valve. Look behind the range for a connector crimped by ten years of cleaning. Look for pipe rusting where it meets concrete, or an unsupported run sagging between joists. You're building a list for the next technician, not a project list for yourself.
Finish with the detectors, since combustion problems show up there long before anybody smells anything. Carbon monoxide alarms belong on every level and near sleeping areas, and they expire, usually between five and ten years, with the date printed on the unit. Replace them on schedule. Keep paint, gas cans, and solvents away from any pilot flame, never heat a room with a range or a grill, and keep generators outdoors, away from windows. For the wider version of what counts as an emergency and what waits until morning, our emergency plumbing hub lays it out.
Related work
More emergency services
Burst Pipe Repair
split copper and PEX, shutoff sequence, temporary containment, permanent fix
→Water Main & Service Line Repair
the buried service line from meter to house, leaks in the yard, replacement
→Slab Leak Detection
warm spots, unexplained bills, acoustic and thermal location, reroute vs. break-in
→Bathroom Leak Repair
ceiling stains below baths, shower pan failures, supply and drain leaks
→Sump Pump Repair
failed floats, discharge freeze, battery backup, spring melt loading
→Where we cover
Front Range cities we write for
Questions we actually get
Gas Line Repair: quick answers
Can I use soapy water to check a fitting for a gas leak?
Only when you smell nothing at all and you're checking a single accessible connection out of curiosity. If you already smell gas, you're supposed to be outside, not troubleshooting. And a bubble test tells you a joint is leaking without telling you whether three others are. That's what a pressure test on the whole system is for.
The gas smell went away on its own. Am I fine?
No, and that's a common way people get hurt. Odor concentration shifts with wind, doors opening, and the furnace fan cycling, so a leak that seems to vanish may simply have moved. Report it anyway. The utility would rather roll a truck for nothing a hundred times than miss the one that mattered.
Who handles gas lines, a plumber or the utility?
The utility owns the line up to and including the meter and responds to reported leaks on any part of it. Everything past the meter, inside your house and out to your grill or shop, is yours, and that work goes to a licensed plumber or gas fitter. Both get involved after a leak: one repairs, the other restores service and relights.
Nothing smells wrong, but something's off?
Describe the appliance and the symptom, and we'll point you at the right kind of help.
Get My Free Quote