Installing and maintaining a septic tank system can be a necessary part of owning a home. The cost of installing and maintaining a whole-home septic system can vary based on many factors so we put together this guide on septic tank installation costs and how to maintain, repair, and replace a septic system.
How Much Does an Average Septic Tank System Cost?
The average homeowner can expect to spend anywhere between $10,000-$25,000 to install a new septic system. However, the exact costs for installing a septic tank system vary based on factors such as location, the size of the septic tank, soil quality, and more. The exact required size of a septic tank depends on how many people occupy the home. For an average home, most septic tanks have a capacity between 1,000-3,000 gallons. Septic system costs can be split into materials, labor, and installation costs.
Septic Tank Cost
The cost of the septic tank itself is primarily determined by its size and can range from around $700 for a smaller septic tank to over $3,500 for a larger one. Size requirements depend on the size of your home and the number of people living in it. All other things being equal, the larger your home and the more people that live there, the more expensive the tank will be.
The smallest septic tanks usually start around 500 gallons and are suitable for a 1-bedroom home with 1-2 people. But septic tank systems can vary in size from 500 gallons up to 3,000 gallons or more.
Average Septic Tank Cost By Size
Here are some average figures for the cost of a septic tank based on its size.
- 500 gallons - $700
- 750 gallons - $1,000
- 1,000 gallons - $1,200
- 1,250 gallons - $1,700
- 1,500 gallons - $2400
- 2,000 gallons - $2,800
- 3,000 gallons - $3,500+
The figures are estimated assuming a polyethylene septic tank, which is usually the cheapest kind. There are also fiberglass septic tanks and concrete septic tanks, both of which are generally more expensive.
As a general rule of thumb, you can expect a fiberglass septic tank to be about 20%-30% more expensive than a polyethylene tank of similar size, and a concrete tank is about 25%-40% more expensive than a polyethylene tank of similar size.
Septic Tank Installation Costs
Buying the actual tank is just a part of the total costs. You also need to consider installation costs. Installing a septic tank is a complex process that requires placing the tank, connecting it to existing water mains, laying pies, and installing the control panel. Soil condition is another factor that can affect costs as the condition of nearby soil affects how the drainage pit is dug and how the tank is situated.
A traditional 1,500 polyethylene septic tank for a 3-bedroom house has an average installation cost of around $3,500. This is a baseline amount, and the actual amount could be higher depending on where you live. For example, installation costs in the Midwest are normally cheaper than installation costs in coastal regions.
There is also a distinction between a conventional and engineered septic tank installation. Conventional systems are typically placed in locations where soil conditions are ideal for percolation. These systems are relatively simple and consist of the tank and branching pipes for wastewater flow, encased in a drain field.
Engineered systems are used in places where soil conditions do not allow for a conventional installation. These kinds of systems require additional pumping systems as water does not flow through the soil as naturally. Local health ordinances may also require newly built homes to have an engineered septic system.
Engineered septic systems usually are much more expensive to install and maintain than conventional septic systems. Whereas conventional systems can cost between $3,000-$7,000 for installation, engineered systems typically cost over $10,000 for installation due to the extra equipment and soli engineering that they require.
There are other subtypes of septic systems such as pressure and mound systems, most of which fall between $5,000-$10,000 for installation costs.
Septic Permit Costs
Additionally, you will need to apply for a septic permit if you are installing a new septic system. Acquiring a septic permit involves having an inspection done to make sure your septic system is up to local health ordinances and engineering codes.
The exact cost of a permit depends on the state where you live. Typically, a residential septic permit costs about $300-$500, while a permit for commercial or industrial locations costs anywhere between $500-$1,500, depending on tank size and the type of septic system it is.
Also, depending on the state in which you live, you may have to apply for other permits such as a building permit, water rights permit, utility permit, occupation permit, and others. Ensure you check with your local housing authority for the specific permits you need to build a new septic tank.
Septic Tank Maintenance Costs
Regular maintenance is an essential part of ensuring your septic tank is in working order and lasts a long time. Common problems with septic tanks may include excess water, clogged drainage systems, strong odors, ground movements destroying pipes, and tree root infiltration into the drainage system.
The average home of 4 people requires septic tank maintenance once every 2-3 years. If more people are living in the house, then maintenance should be performed every 1-2 years.
It is hard to give an exact figure for septic tank maintenance costs as they depend on your location, the severity of the problem, and the type of septic tank system you have (e.g., conventional or engineered). However, most professionals charge somewhere around $300-$400, potentially more if the issue is serious or if you are located in an area with high living costs.
How Long Can a Septic System Last?
Assuming that you perform regular maintenance and use the system in the way it was intended (i.e., not flushing non-biodegradable materials), a decent septic tank system can last for decades. However, even the best-maintained septic systems will need to be replaced eventually.
Common signs of a failing septic system include clogged pipes, degradation of the tank, inability to drain properly, puddles seeping up into your yard, excess plant growth on the surface of your drain field, and contaminated water wells. This last issue is serious and can be very dangerous for your health.
Septic Tank Replacement Costs
Despite what you might think, replacing a septic system is often more expensive than installing a brand new one. Replacing a septic system usually involves removing existing material as well as installing new parts. This involves more time and more labor.
In the best-case scenario, you can get away with just replacing the malfunctioning parts. Common replacement parts include pumps, tanks, pipes, and drainage ditches. The cost of these can vary heavily depending on the type of system you have and the severity of the damage. All in all, replacing existing parts of a septic tank system can cost anywhere between $500-$3,000, not including labor costs and material costs.