Two plastic underground storage tanks placed below ground for harvesting rainwater. The underground water septic tanks, for use as ecological recycling rainwater.

Buying A House With A Septic Tank: A Complete Guide

Andrew Dehan5-Minute read
UPDATED: August 29, 2022

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The further you get from the city, the more likely homes won’t be hooked up to municipal sewage lines. According to the EPA, more than 20% of homes depend on either individual or community septic systems. If you’re considering buying a house with a septic tank, there are several things you must consider before your purchase.

Should I Buy A House With A Septic Tank?

When some people think of a home with a septic tank, they think of an off-grid home. These homes generate their own electricity and heat, and often have well-water. While most off-grid homes have septic tanks, not all homes with septic tanks are off-grid.

Don’t feel like buying a home is as big of an undertaking as chopping wood for the winter. Septic tanks are common and only need routine maintenance to keep working for decades.

How Septic Tanks Work

Diagram of septic system

Septic systems are simple devices. Everything that goes down the drain in your home drains into them through a main drainage pipe. The septic tank holds this drainage long enough for it to separate, with the solid waste (AKA “sludge”) settling to the bottom of the tank. Eventually you will need to have your tank pumped to remove the solids. Anything that floats is filtered out.

The liquid wastewater – or effluent – leaves the tank going to the drain field, or “leach field” as it’s sometimes called. The drain field is a shallow, covered area of dry soil that naturally filters the effluent, slowly releasing it into the soil as groundwater.

To illustrate how this works, let’s say you grind up some food scraps in your garbage disposal. The water you use to flush the drain will become your wastewater, the food solids will sink to the bottom and any oil or grease will float on top and be filtered out.

Too much food waste, or other solids like toilet paper, can clog your septic drain. As you could imagine, a clogged septic system can be messy and costly. Then again, so can a municipal waste system.

There are several pros and cons to weigh with a septic tank.


  • Off-grid. With your own septic system, you’re not reliant on municipal wastewater treatment. If something goes wrong, you can solve it instead of waiting for your local government.

  • More freedom. Septic tanks allow homes to built further away from major metropolitan areas. If you want the freedom to live where you want, you’ll likely need a septic tank.

  • No more municipal sewage bill. While you will need to pay for regular maintenance (like an inspection every 3- 5 years), you won’t have to pay for city sewer with a septic tank.


  • Depending on the size of your tank, its age and the amount of people in your home, you’ll have to have your septic tank regularly maintained. Tree roots grow towards water and can cause unexpected problems. So can erosion or other shifts in the soil. Regular inspections are necessary to try to prevent issues before they become big problems.

  • Groundwater contamination. If your drain field is not properly filtering contaminants, it can affect the groundwater. This can flow into nearby water sources where it can impact drinking water, as well as wildlife habitats.

  • Limited waste disposal. While you shouldn’t flush many things on a municipal waste system, you definitely shouldn’t do it with a septic tank. Items like dental floss, hair and other solids can cause big problems for your wastewater system.

Plumbing issues can be a hassle.

Let HomeAdvisor help you find a plumber today.

How To Get A Septic System Inspection

Scheduling a septic system inspection is like scheduling any other type of home maintenance. Speak with people in your network that have a septic tank and see if they can refer an inspector to you. Check out reviews of septic system companies online and make sure you hire a qualified, licensed inspector.

If you’re buying a home with a septic system, it’s important to make the offer contingent on an inspection. While septic tanks can last for decades if they’re properly maintained, people may not do the proper maintenance on them. Since they’re buried, without an inspection you won’t know what you’re getting into until there’s a problem.

Here are a couple common inspection types and how much they cost.

Visual Inspection

Visual inspections are typically done by the home inspector when buying a house and the cost of it is tied into the home inspection fee. The inspector will ask how old the system is, how often it’s been pumped and when the last full inspection was. The house inspector will check all of the sinks, toilets and other drains to make sure they’re draining correctly, as well as checking the drain field for standing water, which can indicate it’s not working.

A visual inspection is a starting place when buying a home. The home inspector may be able to tell you if something is wrong or if a full inspection is necessary. However, it’s not a thorough inspection and may not be the full story. For that you’ll need a full inspection.

Full Inspection

Full inspections are done by an experienced septic tank inspector and can range in price from $100 - $600, with the average cost being around $390, according to Costs vary based on the contractor, your location, the size of the tank and how easy it is to access.

During a full inspection, an inspector will remove the manhole cover and check the tank’s water level to ensure it’s draining correctly. They will run water in the house to check the drainage speed and be sure the water level doesn’t rise in the tank, being certain the new water is pushing the old effluent to the drain field. To aid in visualizing this, the inspector may dump some dye down the drain to be sure it reaches the septic tank.

After this full inspection, the tank is ready to be pumped. Usually the inspection and pumping is scheduled at the same time and is often done by the same contractor.

Does A New Septic Tank Increase Home Value?

A new septic tank may not dramatically increase you home value, but if you’re trying to sell your home, a working septic system is necessary. A new septic tank may not be a huge selling point, but a faulty septic system can make your home unsellable. Think about it this way: would you buy a home knowing the septic tank needed to be replaced?

A completely new septic system, including new pipes and drain field, can cost $10,000 - $25,000, according to Even if your septic tank isn’t faulty, you may have to replace it if you’re expanding your home. Some municipalities require the tank size to increase if your home sewage needs increase. On average, new septic tanks cost around $6,500 to replace and install.

In short, a new septic system may not add much value to your home, but a faulty or undersized system will definitely detract value. This is the type of

The Bottom Line: Septic Tanks Are A Valuable Home System

If you find out a home you like has a septic tank, there’s no need to be intimidated. Septic systems are like any other home element. Regular maintenance every 3 – 5 years can help keep them in optimal shape and paying attention to what you flush can keep them from getting clogged.

Many homes outside city limits have septic systems, and if this is where you want to live, a septic tank may be part of your new home. If you’re concerned about the septic system, consider purchasing a home warranty plan that covers septic systems. This could help protect you from any surprises and offset the regular maintenance costs.

Andrew Dehan

Andrew Dehan is a professional writer who writes about real estate and homeownership. He is also a published poet, musician and nature-lover. He lives in metro Detroit with his wife, daughter and dogs.