Signs of a Gas Leak in Your Yard, and Whose Line It Is

Gas escaping underground pushes oxygen out of the soil, and the roots in that spot die. That is why a leak often shows up as a brown patch, or a brown stripe that follows the line, in a lawn that is otherwise green. In summer it can look like any other dry spot, which is why it gets missed.

Piedmont lists the signs it trains customers to look for, and they hold for any utility:

• A rotten-egg or sulfur smell outdoors, especially near the meter or along a line
• Dead grass or plants in a patch or line, when everything around it is green
• Bubbles rising steadily through a puddle, a wet ditch or a creek
• Dirt or dust blowing up from the ground for no reason
• A hissing or whistling sound near the meter or a pipe

The odorant in natural gas can be stripped out as gas moves through soil. A leak on a buried line may reach the surface with little or no smell, so a yard leak that only shows up as dead grass is still a real leak.

Leaks in the yard can also travel. Gas follows the path of least resistance, which can be the loose fill around a pipe trench or a crawlspace vent. If you have any doubt, the utility will check with a detector at no charge to you.

The gas utility owns the main in the street, the service line that runs to your house and the meter itself. A leak on any of those is the utility's to repair. On most homes in Spartanburg County that is Piedmont Natural Gas.

Everything after the meter is customer-owned. That includes any pipe that leaves the meter and goes back underground: a line to a detached garage or shop, a gas grill or outdoor kitchen, a pool heater, a generator, a gas lamp post, or a second building. Federal pipeline rules require utilities to tell customers that they do not maintain this buried customer piping, and that it should be checked for leaks and, if it is metal, for corrosion.

Older buried lines are the usual trouble. Bare or poorly wrapped steel pipe corrodes in damp Upstate clay, and a gas lamp or grill line put in decades ago may never have been looked at since.

Calling SC811 before you dig is free and it is the law. Request it at least three full business days ahead. But 811 member utilities only mark the lines they own. On a gas service, that means the line up to the meter. Your buried line from the meter to the grill or the shop will not be painted.

Piedmont says the same thing: lines you had installed, like gas lines to grills, have to be found by a private locating service in addition to 811. If your plastic gas line was buried with a tracer wire, as it should be, a locator can follow it. If it was not, it can be hard to find at all.

This is how most yard lines get hit: a fence post, a sprinkler trench or a new tree goes in where everyone assumed the paint marks told the whole story. If you have gas to anything beyond the house, sketch where it runs and keep it with your house papers.

If you smell gas or hear hissing, treat it as an emergency. Keep people and pets away, do not start a mower, car or anything with an engine nearby, and call 911 or the gas utility from a safe distance. Piedmont's emergency number is 800-752-7504.

If all you have is a suspicious dead patch and no smell, call the utility's emergency line anyway and tell them what you see. They will check it, tell you whether the leak is on their side, and shut off the gas to your line if it is on yours.

A customer-side leak in the yard gets dug up, located and repaired, or the line gets replaced. On an old steel line, replacement with polyethylene gas pipe and a tracer wire is often the better repair. Either way, the line is pressure-tested before the gas goes back on.