Underground storage tanks, or USTs, are tanks and piping that may have been buried in your yard to store petroleum or potentially hazardous substances. Back in the day, these tanks were made of bare steel.

Over time and with enough moisture, bare steel corrodes and could result in petroleum (or hazardous substances, depending on what the tank contained), leaking out and contaminating groundwater. Here are some signs there’s an underground storage tank on your property.

Pipes

Pipes in your yard or basement may betray the presence of a UST. The tanks typically contained petroleum that homeowners wanted to use in their houses, so pipes would carry the oil into the basement. If you see supply pipes or concrete patches in your walls, you may have a UST.

Additionally, check your yard for pipes. When the time came to refill the tank, homeowners would deposit oil through pipes in the backyard. Check in bushes and shrubs as well as your lawn, as the pipes could be hidden from sight.

Coffee Cans

Sometimes, the vents and pipes were covered with metal coffee cans to prevent rainwater and dirt from entering the tank—poke around for Folger’s cans in your yard, as they could be signs of a UST below.

Depressions

When the tank was put in, a company had to remove a lot of earth, deposit the tank, and fill the ground back in. Sometimes, they wouldn’t get everything quite right, so you may notice depressions or small hills in your yard. Dirt may have filled in the tank through severe cracks, resulting in uneven landscaping.

Get Professional Help

If you don’t have ground-penetrating radar, you won’t know for sure if there’s a UST on your property. Whether you suspect there’s a storage tank or you just want to be sure there isn’t, contact a professional, and they’ll assist with detection and removal.

With these signs there’s an underground storage tank on your property, give your basement and yard a once-over to ensure there’s no danger of chemicals or oil leaching into your local groundwater.

Denise Lockwood has an extensive background in traditional and non-traditional media. She has written for Patch.com, the Milwaukee Business Journal, Milwaukee Magazine and the Kenosha News.