Cost and Funding

The Costs and Financing of Septic Systems

Septic systems, when properly designed, installed, operated and maintained, provide effective treatment of household sewage at a very reasonable cost. Unfortunately because the septic system is buried "out of sight" in the back yard, it often becomes "out of mind."

Many rural residents have had the idea that "disposing of sewage" should have little or no cost. We know now that the "treatment" of our sewage necessary to protect our family health and the community water supply will have a cost. Persons using municipal treatment systems pay both connection fees and user fees.

Would you buy a car, then never change the oil until the engine starts knocking or seizes up? Of course not. Why would you buy a septic system for $3,000 to $10,000 and then never take care of it?

There are three kinds of costs associated with a septic system: the original installation costs, the maintenance and repair costs, and the replacement costs if things go wrong. Because proper steps taken in the installation and maintenance will prevent many of the replacement costs.

The original design and installation costs of an individual on-site septic system typically range from $3,000 to greater than $10,000, depending on the size of home, the site conditions and local ordinance requirements. The installation costs of multi- household systems in small rural communities, around lakes or in clustered suburban developments will also have a wide range. The variables contributing to the wide range include the number of homes on the system, the distances between homes, the distance to the soil treatment site, availability of land for the site and the type of treatment system necessary as determined by soil conditions. Several documented installations have cost between $3,900 and $16,000 per home. Installation costs are one-time costs that last for 20+ years.

The annual operation, maintenance and repair costs occur over the life of the system. Traditional installations last 15 to 40 or more years. The annual costs of septic systems include the regular cleaning or pumping of the tank on a two or three year interval.

The typical annual costs of an individual drainfield or mound system range from $30 up to $500 with the high end including replacement costs of pumps in mound systems. The annual costs with systems including constructed wetlands or sand and peat filters are often $50 to $1,700, depending on the discharge method and monitoring requirements. Annual costs for multiple-household systems are typically $200 to $1500 per household. The costs of contracted monitoring raise the lower end costs for these systems.

The typical total cost for individual systems over a 20 year period is $6,300 to $13,000 for trenches and mounds, or $13,500 to $32,000 for alternative treatment systems. For multi- household systems, typical trench or mound systems range from $18,500 to $25,000. Alternative treatment systems typically range from $18,000 to $44,500 for 20 years of service.

Financing of the original design and installation costs can be a major hurdle for some homeowners. The state of Minnesota, through the MPCA, Department of Agriculture and the Department of Trade and Economic Development has created several special loan or grant programs that may be available through local lending institutions, county water plan programs or other agencies. Contact your local planning and zoning, environmental services or Soil and Water Conservation District about these programs.

With all of the new systems being installed around Minnesota to replace old, non-conforming systems, homeowners must learn how to use and take care of them. If people don't learn these things, the system is likely to fail within 3 to 10 years and the owner will get the opportunity to buy another system. The answer to these unnecessary costs is to learn how to use and take care of it!

Preventing Costly Drainfield Repair

A septic system's effectiveness is greatly influenced by how it's used and maintained. Treatment of disease-causing pathogens and nutrients is done in the soil part of the system.

This soil treatment system can be a drainfield, mound, or drip dispersal unit. Overloading it with water and solids can clog the soil. Large amounts of water flowing through your system are damaging; solids might be flushed out before the tank separates them from the water. An example is the washing of many loads of laundry on the same day. Spacing heavy water-using jobs, such as laundry, throughout the day and week helps prevent overloading. Water from roof drains or snow melt flowing onto or collecting in drainfield areas should be avoided.

Lack of proper septic tank cleaning can cause biological overloading. By adding "dirty" water to the soil treatment system, a thickened layer called the biomat becomes thicker than desired. The soil's ability to accept water slows. Effective treatment is decreased.

Driving heavy vehicles on the drainfield or mound system during or after construction can damage it. Soil treatment depends on natural, uncompacted soil to treat wastes. This is especially important in winter, when a vehicle's weight can drive the frost deep into the soil. This prevents effective treatment from occurring. Nothing heavier than a riding lawnmower should be driven over any part of the septic system. In addition, people should stay off the area in wintertime to prevent freezing.

Good vegetative cover, usually grass, is planted over soil treatment systems. Mow it regularly. Mowing is necessary to encourage growth without using fertilizer. The vegetative cover helps remove nutrients such as nitrogen and phosphorous. Do not plant trees or other plants with deep roots within five feet of the soil treatment system. Be sure to keep gophers and other rodents out of the soil treatment area.

By following these management practices and others found in the Septic System's Owner's Guide, Extension Publication PC-06583, you will prevent costly repairs & protect your family's health & environment. For more information, contact your local Extension office.