Solved! How to Find Your Septic Tank

Locate your septic tank to stay on top of regular maintenance tasks and prevent septic system backup.

By Timothy Dale | Published Feb 14, 2022 11:18 AM

how to find your septic tank

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Q: When I bought my home, I was told the house’s septic system needs to be cleaned out every three to five years. I recently tried to locate my septic tank, but I can’t remember where the previous homeowner said it was buried. Is there a way to find my septic tank without knowing its general location?

A: A septic tank should be pumped regularly, or else it can cause your home’s entire wastewater system to back up. If you aren’t sure where your septic tank is buried, it can be difficult to spot and repair leaks or flooding before they become more expensive problems.

Even if you don’t know the approximate location of your septic tank, you can find it using one or more of these potential solutions.

Inspect your yard for signs of the septic tank.

One of the easiest ways to locate a septic tank is to simply go for a walk around your house. Septic tanks can commonly be spotted by looking for signs of a large buried object in your yard. A probable indicator would be a large divot or hill, which often occurs when the initial hole dug for a septic tank is too large or small, respectively.

Also look for parts of the lawn that are patchy and difficult to grow grass or plants on. If there isn’t a significant amount of dirt covering the tank, then it’s likely that the area will have very sparse plant growth. Should these methods fail, the odor from an untreated septic tank will gradually build until you might narrow down its location by smell.

There are a few spots where you don’t need to search. Typically, a septic tank won’t be installed under or near a well water system, and they’re rarely buried under paved surfaces, like patios, sidewalks, or driveways. You can also rule out areas close to any major landscaping or yard features, such as a pool.

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Look for the septic tank lid using a soil probe.

Septic tanks have one or two lids, depending on whether they have a single compartment or dual compartments for filtering and breaking down wastewater material. These lids tend to stick up from the main tank, so they can often be found with a soil probe (which makes for a highly effective septic tank locator tool). You can alternatively use a piece of rebar or any long, narrow object that’s hard enough to break the soil without much effort. Regardless of what you use, your probe should ideally be at least 4 feet in length. Make sure to not drive the probe too hard into the ground while probing; otherwise, you could damage the septic tank lid.

Though, how deep is a septic tank? Unfortunately, septic tank installers don’t bury every tank at the same depth, so your septic tank may be buried as little as a foot underground or it could be covered in greater than 4 feet of soil. You’ll want to use a hammer to help drive your probe down into the soil to find a deeply buried tank. A metal detector can also be used to locate septic tanks, and it may even detect the metal handles of septic tank lids to narrow down your probing.

When you locate your tank, mark the location with a lawn ornament, small sign, or measure the distance from the two near corners of your home and keep a record of this information for future reference.

Related: How Much Does a Septic Tank Cost?

Follow the main sewer line from your home to your septic tank.

Septic tanks are connected to the main sewer line or waste pipe of a home, so you can follow the direction of this pipe to help pinpoint where your tank is buried.

Look through the basement, cellar, or crawl space to find the main sewer line running into your home. This pipe will generally be about 4 inches in diameter and made out of cast iron or heavy PVC pipe. When you locate the pipe, note the spot where it exits your home. Find the corresponding area outside and walk directly away from the house. Drain pipes are usually laid in straight lines, so you can be confident that the septic tank is buried somewhere along where the main waste pipe exits the home.

Follow the estimated path of the drain line and look for any signs that a septic tank has been buried in the area. A probe can help verify that you have found the tank’s location, and it’s also a good idea to use a shovel to uncover the lid. Mark the location with a lawn ornament, a small sign, spray paint, or measure the distance from the two closest corners of the home and keep a record of this information somewhere safe so you can refer to it in the future.

how to find your septic tank

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Consult local county records for your home’s septic system permit.

A septic tank’s location can impact nearby water sources, so installers commonly must apply for septic system permits to mitigate the risk of environmental damage or drinking water contamination. Thanks to this practice, your local county should have a record of where your septic tank is buried.

If this record was provided with the purchase of your home, you can review the septic system diagram to determine the size of your tank and the number of lids it has to help narrow down its location. Some older homes may not have these records, however.

Related: The Best Septic Tank Treatments

Check with local septic maintenance companies.

If your local government doesn’t have records of your septic tank, then it’s possible that it was installed without a permit or is an older system predating permit requirements. Either way, any septic system would have needed to be pumped at least once every three to five years to stay in good working order. With this in mind, you could contact local plumbing companies that offer septic maintenance services to see if the tank was previously pumped by them and if they know the tank’s location.

how to find your septic tank

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Ask your neighbors or contact a professional.

While it differs between neighborhoods, it’s possible that your property’s septic tank was buried in a similar location as your neighbor’s tank was on their property. You may be able to locate your septic tank simply by asking them.

Even if neighboring system systems weren’t laid in the same spots in relation to their houses, your neighbors may still have information about where your septic tank is located. Contact the neighbors who have lived in the neighborhood the longest. It’s feasible they could have seen your septic tank being serviced at some point in the last five years, in which case they may be able to point you in the right direction.

If you run out of DIY options and still haven’t found your septic tank, hire a professional to locate your tank to ensure it doesn’t go unmaintained for too long.

Related: Solved! How Long Do Septic Tanks Last?