Gas piping sometimes runs under a slab to reach a furnace, water heater, range or fireplace. Like water lines, it can corrode or be damaged over time. A gas leak is a safety issue first and a plumbing job second.
If you smell gas: do this first
- Get everyone out of the house.
- Don't switch lights, appliances or anything electrical on or off. Don't use a phone inside.
- From outside, call the gas utility's emergency number or 911.
- Don't go back in until the utility says it's safe.
Natural gas has an added smell like rotten eggs so leaks can be noticed. Propane also carries an odour and settles low, so the smell may be strongest near the floor.
Other signs of a gas line problem
- A hissing sound near where gas lines run
- Gas appliances with weak or unusual flames
- A gas bill higher than usual
- Dead patches of grass along an outdoor gas line
Once the utility has made it safe
A plumber who works on gas piping pressure-tests the system to confirm a leak and narrow down which section is losing pressure. If the leak is in a section under the slab, the options are to repair it in place or to reroute the gas line above ground.
Why rerouting gas lines is common
A gas line under a slab is hard to inspect and hard to reach. Moving it above ground, through the attic, walls or along the exterior, keeps it accessible for the future. It's the same idea as a water line reroute.
Water and gas together
If you're also seeing warm floors or a moving water meter, the water lines may need attention too. See slab leak detection, and for anything urgent involving water, emergency slab leak repair.
Once the house is safe, call for a quote on gas line or [slab leak repair](/) work.
Gas Line Leak Under Slab Services We Offer
✓Gas Pressure Test
Confirms and isolates the leaking section.
✓Gas Line Reroute
Moves gas piping above the slab.
How it works
- 1
Make safe
Utility or emergency services make the house safe.
- 2
Pressure test
Gas piping tested to confirm and isolate the leak.
- 3
Repair or reroute
Section repaired or moved above ground.
- 4
Re-test
System tested before appliances are relit.