It’s lurking under your yard.
What is? you ask.
You name it. “Water lines, sewer lines, gas lines and, in many instances, electric and cable — if you don’t see it overhead then it’s underground,” says Tim Carter, founder of the Web site Ask the Builder.
Imagine under your yard a veritable octopus of pipes and wires.
And that’s just the predictable stuff. In his years as a contractor, custom home-builder and expert witness, Carter has found all sorts of nightmares under the grass: Forgotten septic tanks. Old wells. The hollow foundations of long-disappeared homes.
“In your yard you could have a main trunk-line sewer — we’re talking eight or 10 feet in diameter,” he says.
So what if you, Joe Homeowner, want to put in that new fence or plant a few bushes? It’s all enough to make you nervous to dig even a shovelful of earth.
Here are some of the biggest concerns — and what to do about them.
1. The lurker: Electric and gas lines
The danger: “Probably the two most dangerous ones to work around in your yard are underground electrical lines and underground gas lines,” says Don Vandervort, a home-improvement expert and founder of HomeTips.com. “Both can cause fires.” Not to mention electrocution (in the case of cutting an electrical line) or other serious injury.
Americans strike underground utilities about once per minute, on average, according to a report last year by the Common Ground Alliance, a group of utilities, fire marshals and others that focuses on protecting underground utility lines and the safety of people who dig near them. The top reason for the incidents? People failing to call before digging, to find out where their utilities are located.
Avoiding trouble: Step one: Call 811. “It is the law. A lot of people don’t know that,” says Susan Browning, who manages the public safety program for Duke Energy, which serves five states. That’s true whether you’re a professional with a backhoe or a weekend warrior putting up a fence. As Vandervort puts it, “There is nothing that will make you an outcast faster than knocking out the cable TV in your neighborhood.”
811 is a national call-before-you-dig telephone number that patches you in to one of 62 centers in all 50 states and the District of Columbia. Your local utility will send someone out — free — to mark the rough location of their lines with spray paint or flags so you or your contractor won’t hit them. (Find out more here.)
Make sure you plan ahead. “Most states require two working days before they can come out,” Browning says. “South Carolina requires 72 hours’ notice.”
Once your yard is marked, don’t dig with abandon. For one thing, not every pipe gets marked. (See “How to Dig,” below.)
A final rule of thumb: Don’t believe the telephone pole, says Vandervort; just because a home has a utility pole out front doesn’t mean some of the utilities weren’t buried.
2. The lurker: Sprinkler systems
The danger: Anything that distributes water on your property, such as an in-ground sprinkler system, is installed “often not more than a few inches below the surface — just because it’s easier and cheaper and because homeowners often do it themselves.” That means the PVC pipes are easy to hit.
Rupturing a sprinkler system is less a hazard than an inconvenience and a mess, Vandervort says. Still, why let it happen?
Avoiding trouble: Here’s how Vandervort avoids it:
He finds where the water is coming from (that is, the water supply pipe, and where it serves the sprinkler pipe). From there, the sprinklers are often laid out with PVC pipe in more or less straight lines, he says. “I often start at one sprinkler head, and work from one to the next,” carefully digging around them to unearth them as necessary, he says.
 | Paranoid? Get an underground shelter |
A related note: “Low-voltage lighting [for landscaping lighting and the like] is often practically along the surface of the soil” as well, Vandervort says. But note that those wires don’t need to take a straight line from one light to the next.
3. The lurker: Old oil tanks
The danger: Many homes relied — and still rely — on oil fuel. That fuel may be contained in tanks buried in the yard— single-wall steel tanks whose life span is only 10 to 15 years, says Daniel Friedman, an inspector and consultant and author of the home inspection site InspectAPedia.com, which contains oodles of great information about dealing with old oil storage tanks. The tanks can leak because of acidic soil — or because someone hits them — and make messes that can cause tens of thousands of dollars in damage, Friedman says.
Avoiding trouble: First, track down the tank. Look for fill or vent pipes in the yard or sticking out of the house. Look under rocks or even coffee cans for the fill pipe, Friedman says.
A specialty company can test surrounding soil and pressure-test the tank to check for leaks. If you suspect any water, have the oil company pump it out.
If there are no leaks, a buried tank can be abandoned in place, Friedman says. That could be as simple as making sure it’s empty and then leaving it — or emptying it and filling it with something like sand (more expensive).
What if you do find a leak? Your first job might be to get on the phone: In New York state, for instance, if an oil leak of any real consequence is found at any tank, it has to be reported to New York’s Department of Environmental Conservation within two hours, Friedman says. More about what to do if you find a leak is here.
