Gas line problems are among the most serious issues a home can have, and recognizing the warning signs early can prevent a dangerous situation. The most telling signs include the smell of rotten eggs near a gas appliance or anywhere in your home, a hissing sound near a gas line or meter, dead patches of vegetation in your yard over a buried gas line, and unexplained increases in your gas bill. If you suspect a gas leak, leave the house immediately and call 9-1-1 and your gas utility before calling a plumber.
The Smell of Rotten Eggs or Sulfur
Natural gas is odorless in its natural state, so gas utilities add mercaptan — a chemical that produces a distinct rotten egg or sulfur smell — specifically so leaks can be detected by household members. If you smell this anywhere in your home, treat it as a gas leak until proven otherwise. Don’t flip light switches, use your phone inside the home, or try to find the source yourself. Get out and call for help from outside.
A faint smell near a burner that dissipates immediately when you turn on the range is sometimes just residual gas clearing from the igniter — but if the smell persists or appears where there are no appliances, that’s a different matter entirely.
Hissing Sounds Near Gas Lines or Appliances
A hissing or whistling sound near a gas meter, flexible connector, or appliance connection can indicate gas escaping under pressure. This is distinct from the sound a furnace or water heater makes when running normally. If you hear an unfamiliar hissing near any gas connection point — even a quiet one — treat it seriously. Pressurized gas escaping through a small opening creates exactly that sound.
Dead or Discolored Vegetation Above a Buried Line
If you have a gas service line running from the street to your home or a gas line to an outdoor grill or outbuilding, a buried leak will displace oxygen in the soil and kill the vegetation above it. A strip of dead or yellowed grass in an otherwise healthy lawn — particularly one that follows a straight line — warrants a call to your utility’s dig-safe line and then a licensed plumber to investigate.
Colorado’s clay soils can hold gas in a concentrated pocket longer than sandy soil, which means a buried leak may remain localized for a period before migrating toward a structure. That’s not a reason to delay — it’s a reason to act before the gas finds a path into the home.
Higher Gas Bills Without a Usage Explanation
A slow leak in an interior gas line may not produce a detectable smell at low concentrations but will register on your utility meter. If your gas bill is rising and you haven’t added appliances, changed your thermostat settings, or had an unusually cold stretch, a supply-side leak is worth ruling out. Your gas utility can check the meter and perform a basic pressure test.
- Rotten egg or sulfur smell anywhere in the home
- Hissing sound near a gas line, meter, or appliance connection
- Dead or yellowed vegetation in a line above a buried gas pipe
- Unexplained increase in monthly gas bills
- Visible corrosion, rust, or physical damage on exposed gas piping
- Appliances that pilot poorly, flame out frequently, or have an orange/yellow flame instead of blue
Appliance Performance Issues That Point to Gas Supply Problems
If your gas range burners have an orange or yellow flame instead of a clean blue one, or your furnace or water heater is short-cycling and producing soot around the burner area, the problem may be insufficient gas pressure or a partial obstruction in the line. These symptoms can also indicate combustion issues rather than a supply leak, but either way, a licensed professional needs to evaluate the equipment and the line.
Gas line work — installation, repair, and pressure testing — requires a licensed plumber or gas fitter in Colorado. Done’s team handles gas line inspection and repair throughout the Denver metro. For non-emergency concerns, our pipes and lines service covers gas line diagnostics and repair. For any situation where you suspect an active leak, leave the premises and call 9-1-1 first, then contact Done’s emergency plumbing line once you’re safe.
