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How Close Can You Build To a Septic Tank in 2024? What You Need To Know!

cleaning septic tank

Approximately 25% of homes in the US have dedicated septic systems1. They’ve proven to be reliable and efficient, but let’s say you want to build a house. What’s the safe distance for that? A full foundation must be at least 10 feet from the tank and 20 feet from the leaching field. If it’s a slab foundation, you need a 10-foot gap between the slab and the tank; the same is true for the leaching area.

Is there a difference between federal and state laws? You’ll find the answers right here! We’ll also go over the required distance for wells and gulches. Next, we’ll learn about the nuances of selling a house with a septic tank, how to find it on your property, and how long septic systems last. Let’s get to it!

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What is a Septic Tank? How Does It Work?

Crafted from plastic or concrete, a septic tank is essentially a huge container and treatment structure that’s buried underground. It has one single purpose: to dispose of the wastewater from your house (the drains, showers, and bathrooms). To do that, it breaks down the waste into two major components—solids and liquids. The solid matter sits at the bottom of the tank, and it’s up to the property owner to pump it out.

As for the liquids, they flow into the leaching area. A perforated piping system runs through a leach field/covered excavation. It works as a filter and ensures the liquids are absorbed into the soil and evaporated through the surface. A septic system consists of a tank and soil absorption field. They’re mostly found in rural areas; in big cities, wastewater is handled by government-owned sewer systems.

Installing septic tank
Image Credit: Phattara Away, Shutterstock

Full House Foundation: The Safe Distance

A house foundation is part of the structure that sits below ground and holds the whole construction together. A full foundation has a full-fledged basement (usually 8 feet deep) built with poured concrete walls for structural integrity. All that digging won’t go unnoticed by the tank, so you must keep the right distance.

Federal US laws obligate property owners to build 10 feet away from where the septic tank is located. That way, you won’t have to worry about landslides, wastewater ending up in your basement, or anything else. And what about the leaching field? Make sure that the house, garage, or whatever you’re building is 15–20 feet away from that area.

What Are the Rules for Slabs?

Concrete slab foundations are incredibly popular in the States because they’re affordable and require little preparation. With a slab foundation, the plumbing pipes are buried below the layer of concrete. But, since they don’t run as deep as full foundations, the required distance between the tank and the leaching field is the same: 10 feet. Concrete columns for a deck, in turn, are allowed to be 5 feet from the tank/leaching area.

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Regulations for Wells and Gulches

Do you have a well or a stream in your yard? Then the tank should be installed 25–50 feet away. We recommend doubling that distance to be 100% sure your drinking water won’t be contaminated. The drain field must be at least 150 feet away. As for gulches, the required distance is 25 feet.

an old water well at a farm
Image Credit: reijotelaranta, Pixabay

Don’t Forget About the Leaching Area

The septic tank and the leaching field are a part of the septic system. However, they are NOT the same thing. You need to keep a proper distance between them to ensure proper functioning. So, how far should the leaching area be? The requirements aren’t as strict, but mostly, it will be 50–60 feet between the tank and the drain field. Also, the average leaching area pipe is usually 3–4 feet wide and 3–4 feet deep.

What Does the State Have To Say About This?

We just checked the federal build codes, and according to the regulations, the minimum distance is 10 feet for any type of construction. However, you must also consider the state requirements. Yes, in a way, it all comes down to local laws and regulations. So, before you build a foundation, check in with the local authorities. Never start any construction work until you have the law’s approval.

Here are setback requirements in various states:

State Distance
  • Florida – 5 feet
  • California – 5 feet
  • Ohio – 10 feet
  • Arizona – 10 feet
  • Texas – 10 feet
  • New York – 10 feet
  • New Jersey – 5 feet (10 from the drain field)
  • Mississippi – 5 feet (10 from the drain field)
  • Minnesota – 10 feet (20 from the drain field)

I Have a Septic Tank Installed. Can I Sell My House?

Of course, you can! As long as the tank meets the local regulations and is up to code, you shouldn’t have any problems. However, it might “scare away” people used to a sewage system. In contrast, folks that love the idea of owning a private sewage system will find it to be a big pro. In any case, we recommend being upfront about your septic tank and informing potential buyers in advance.

Here’s what you need to share with them to be crystal clear:
  • Where the tank is located
  • Which systems are connected to it (like a leaching area, for example)
  • Changes that have been made to the tank (if any)
  • The maintenance routine
  • How old is the septic tank/system

Additionally, if you’re selling the house on the open market, local mortgage companies will, most likely, request an inspection of the septic tank. They’ll check whether it’s in decent condition and when it was last emptied/pumped. An inspection will also help reveal potential issues with the system that you should fix before selling the property. Otherwise, it will have a negative effect on the selling price.

Lid of a rural septic tank
Lid of a rural septic tank (Image Credit: W.carter, Wikimedia Commons CC0 1.0 Universal)

How Do I Find the Septic Tank?

If you bought a house recently or don’t know where the tank is located, the best thing to do is look for a manhole. It might not be easy to find, but if you see a big, round cover on the ground, it probably leads into the septic tank. If you have access to the original drawing of the house, you can locate it easily. Finally, you can also contact a contractor or a septic service provider to help you.

Pavers Over a Septic: Is That Legal?

No, you are not allowed to put pavers over a septic tank. Doing so is a violation of state laws. Septic tanks can’t handle extra weight and damage easily. Fixing a broken tank will cost you a lot of time, energy, and, of course, money (up to $3K, with most paying $700–$2,000). Besides, if you put pavers over the tank, you’ll block access to it in the future. However, plants, flowers, grass, and tarp can be put over a tank.

What About a Driveway?

The same rules apply here. Even if you don’t have anywhere else to build your driveway, that’s still not a good enough reason to lay it over the septic system. This is especially true for the leaching areas, as they heavily rely on oxygen and the microbes found in the soil to dispose of the liquids. A layer of rock, sand, and cement will interrupt the natural process of evapotranspiration.

How Long Do Septic Tanks Last?

On average, a well-constructed plastic tank should run for at least 40 years. Steel tanks, in turn, go on for 2–3 decades, which is still quite impressive. Regular maintenance, on-time pumping (ideally, every 3–5 years), and water conservation will help you extend the tank’s lifespan. Clogging by tree roots, organic waste buildup, and flooding (with groundwater) are the most common issues with septic systems.

As for leaching fields, they usually work for 15–25 years but can last for up to 50 years. Again, this depends on the area and maintenance. As long as you don’t park heavy vehicles dangerously close to the leaching area (or the septic tank, for that matter) and avoid using harsh chemicals in the washing machine, the septic system will run for several years.


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Septic tanks aren’t cheap (it costs approximately $4,000 to build one), but they last for many years and do an excellent job of handling wastewater. Now, if you have a septic system installed on your property and plan on building a house or a garage, it’s vital to keep the tank and the leaching at a safe distance from the structure.

Comply with the local laws to avoid trouble with the authorities. You’ll be golden if you follow our tips and tricks and double-check everything before laying the foundation. Oh, and don’t forget to keep an eye on the septic system to stay one step ahead of potential issues!

See also:

Featured Image Credit: M G White, Shutterstock


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