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How To Find a Septic Tank Location in an Old House (Tips and Techniques)

how to locate a septic tank

How To Find a Septic Tank Location in an Old House

Every homeowner should know the location of their septic tank. It helps tremendously as you run into different septic system problems. However, sometimes when you move into an older home, it can be a real chore to locate the septic tank.

In this article we’re going to review the importance of your septic tank and how to tell if you even have one. From there, we’ll dive into some steps you can follow for finding a septic tank in an old house or property.

Importance of Locating Your Septic Tank

There are a number of reasons why you should know where your septic tank is located. For one, it helps you check and troubleshoot your septic system.

Knowing where your septic tank is will also help you with future work you do around the property. Avoiding damage to the tank and its ancillary pipes can’t happen unless you know where it is.

If you bring in a pro, they’ll be able to spend some time and find your tank. However, if you already know where the tank is then you can save some time.

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How to Know if You Have a Septic Tank

If you recently moved into a house, you might not even know if you have a septic tank. An easy way to find out is to check out your water bill.

If you have a septic tank, you’ll notice a $0 charge for sewer services.

The location of your house is also a good indicator. If you are in a rural area, the chances are pretty high that your house has a septic tank.

Where Can’t Your Septic Tank Be?

In the next section, we’ll look into the different techniques to find your tank. But first, it’s important to point out that there are locations where your tank cannot be. This will help narrow down your search.

Under Paved Surfaces

A tank can’t be under any paved surface. This means a driveway or parking spots.

In the House

This might seem obvious to most people. Septic tanks can’t be in your house anywhere. There are clues in your house that will point you in the right direction, but the tank is always buried outside somewhere. Can you imagine the stink!

Immediately Next to Your House

Not only can tanks not be in your house, but they can’t even be near your house. There is code that requires all tanks need to be a minimum of 5 feet away from your house.

Under the Patio

From the same line of thinking, you also can’t have a septic tank under your deck, patio, addition, shed, etc.

If you see a structure in your back yard, don’t even look there for your tank.

Next to Your Well

If you have a well, then you can rest assured that there’s no tank near it.

Under Trees

Nobody should put trees above or next to their septic tank.

Since your house is old, there’s a chance that this rule might not work. Someone could have come along and planted a tree decades after the tank was first installed.

If your tank is under a tree, you can expect to have constant blockages and problems with your septic system. It’s always suggested to remove all trees that are near your septic system.

How to Find Your Septic Tank

Since your house is older, you might not know the original owner. That means you can’t just ask someone where it is.

The good news for you is that there are a number of ways to locate your septic tank – no matter how old your house is! Keep in mind the areas that your tank can’t be before reading ahead.

Look at the Drawings

Every septic system that was installed with a permit has a drawing associated. These drawings are public records and you can request them at your county’s health department.

With some older houses, it’s harder to get your hands on the drawings. It’s still a good first step because it will be the most detailed way to find your tank.

These drawings give a location, a flow diagram, and components used in your septic system.

Visually Inspect Your Yard

For most people, the easiest way to find your tank is to visually inspect your yard. There are some clues to look for, so you get to pretend you’re a detective for a little bit!

The tank is going to be buried in your yard somewhere. For older houses, the soil around the tank has had more time to settle over the years.

Here are some visual clues that you found your septic tank:

Greener Grass than Usual

Your septic system will release liquids and fertilizer into the surrounding soil. Seeing an area of your lawn that is super green is a clear sign that your tank or some other part of your system is buried there.

Some people choose to go a few days without watering their lawn to make the difference more noticeable. As most of your lawn withers, you’ll see the green grass stick out.

Dead Grass

If you have a sizeable patch of dead grass, this could be an indicator of your tank. It means that the original installers did a poor job putting in the tank. It could also indicate a problem in your system.

Thawed Grass

For people in colder climates, check your lawn early in the morning. See which patch of grass thaws quicker than the others.

You’ll have good luck if you go out when the dew on the grass is frozen and look around.

High or Low Spots

A small hill or pit in an otherwise flat yard is a dead giveaway. A lot of people will use this as a clue that their tank is buried there.

Look at the Pipes

If you can’t find some clues outside, let’s check inside. You already know that your plumbing drains to your septic tank, so that means that there’s a pipe that leads from your house to the tank.

In your crawlspace or basement, you’ll find a pipe (typically 3-6 inches in diameter). It should be one of the only pipes that leave your house, and it will punch through a wall.

This is the pipe that goes right to your tank. It’s like a rainbow leading to a pot of gold, but grosser.

Exit your house and go to your lawn immediately where that pipe leads. Your tank will be 10 to 30 feet from this exact location. The pipe will be a straight line, so it’s easy enough to follow it. You also know that your tank can’t be within 5 feet of your house, so you can move that far away.

Grab a soil probe and follow the line. Every 2 or 3 feet, gently push the probe down a few feet. You’re going to be searching for a hard, flat material – typically concrete, polyethylene, or fiberglass.

When you find the hard surface, congratulations! You’ve struck gold – that’s where your septic tank is.

Use a Pipe Camera

A higher-tech solution is to use a pipe camera. This is a snake with a camera at the end. You can feed the line in and take a look at what’s going on. Eventually, you’ll reach your septic tank and you can go outside and follow the path.

This also allows you to see any blockages or obstructions in your line. On top of that, the pipe camera lets you visually inspect the inlet of your septic tank.

Call a Pro

If all else fails, you can always bring in a professional. They will know exactly what to do and where to look. You might even see them using some of the steps detailed above, but these pros will have equipment and knowledge that goes beyond what a DIY-er can do.

Safety Tips While Searching for an Old Septic Tank

Since your house is older, you need to be on the lookout for a few additional safety hazards. During this process, if you find sinking soil in areas that might house your septic tank, be very careful.

Do not go near these areas because it could be an indication that your tank or system has collapsed.

Walking in these areas could cause you to fall through and into your tank which is very likely to be fatal.

Additionally, tank covers that are wooden or makeshift need to be avoided. The last thing to watch out for is rust on any part of your septic system that you find.

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