After your septic tank design is approved, the best way to get a precise appraisal of the septic tank costs is to send your design to multiple licensed installers of septic systems. The second best way is to ask around and do some searching online. The prices you will find below are rough estimates and you should ask a licensed installed for an accurate price quote. In addition to the installation costs, septic tank systems will also require repair and maintenance (septic tank cleaning and pumping). Routine maintenance will help you avoid replacing the entire system, which would cost a whole lot more.
Septic System Costs
Generally speaking, you have three options when considering a new septic system.
- Standard Septic System – $1,500 – $10,000. More information below.
- Cluster Septic System – These systems share a drain field between more than one home in an area. These can cost between $4,000 to $7,500 or more, but the cost would be shared among all homes using the same cluster system.
- Engineered Septic System – These are complex systems that are usually developed for special situations. The cost of these systems is between $5,000 and $20,000.
- Pressure Systems – $3,000 – $5,000.
Standard septic systems use gravity to move the effluent to drain fields where the run-off is filtered. For a level site with a three bedroom house a standard septic system will cost between $1,500-$10,000 depending on where you live in the country and who installs it. The costs for these systems will go up depending on the type of soil; for example, more drain fields are required for silty soils and there is a higher risk of septic tank failure. Building the drain field is fairly in expensive. The drain field vaults typically cost $25 – $40 and quality drain field gravel will cost between $9 and $12. If you decide to use plastic vaults instead of the regular gravel vaults they will cost a few dollars more each.
The minimum size of the septic tank is set by local and state laws, so make sure you check those before you start building your system. The most practical choice is a concrete septic tank. A 1000-gallon concrete tank will cost between $500 and $700 when delivered to a site within 50 miles. A 1200-gallon concrete tank delivered to the same location will cost about $100 more.
Pressure Septic Systems are relatively new and will cost more in places where they are scarce and only a few contractors install them. As the systems become more popular the price will start to come down. A small pressure septic tank system or a bottomless sand filter will cost $3,000 – $5,000. The sand filter system does not require concrete, plywood or vinyl liners. With the pressure system, keep in mind that it is electrically powered and most states require that you hire an electrician to do the wiring, but some will allow the installer to do it.
The price estimates you receive will depend on the septic system design, the health codes in your area, and how many licensed installers are in the area. In some parts of the country the cost for parts is 50% higher than the rest of the country.
Septic System Maintenance Costs
With a new septic system, drain field or mound septic system installation you can expect between $30 – $500 in annual maintenance cost. It is rare that you will have to pay up to $500 unless something has to be repair or replaced (septic tank pumps are often the culprits of high maintenance costs).
A standard trench system with a gravity tank only needs to be inspected and pumped once every 1 – 3 years. The pumping cost of these systems is usually between $75 and $150.
If the septic system is constructed with sand and peat filters or wetlands, the annual cost are between $50 and $1,700. The cost will depend on the monitoring requirements and the discharge method.
A properly built and well taken care of septic system can potentially last 20 – 40 years or longer. Some systems may require special septic tank treatments or periodic replacement of pumps. If you are not experienced with septic systems then I recommend that you learn as much as you can about the system you have installed or are going to install at your home. The more you know the fewer problems and expenses you will have in the future.