Porter's Wisconsin Inspections, LLC
Southwest Wisconsin Residential &
Light Commercial Inspector
(608) 583-6024
(800) 360-2458


Septic systems come in various types of designs. The purpose is to recycle waste water without contaminating our water reserves or environment.

If you have never lived on a rural property you most likely do not have experience with septic systems. If you have or do live in the country then you still may not fully understand these systems. I will attempt to explain them in terms we all can understand.

Once you have the basic concept of a septic system, it does not matter what system is used the end result is always the same. Waste is broken down and the environment and the water table are not contaminated. There is certain criteria, that needs to be met to do this though, and because of this criteria various types of systems may need to be installed.

Locations for the installation of the septic system will have varying soil types at various soil depths. Some soils are better suited to drainage than other soils that may hinder drainage. Some soils are shallow to bedrock as well and could allow non-treated wastewater to seep down cracks in rock strata to the water table below.

Depending on the type of system to be used there needs to be at least 36" of proper drainage soil below what is called the infiltrative surface. This means below the drainage pipe and material used such as gravel that is in the drain field area.

A soil evaluation will be performed before installing a new system by a certified soil tester to determine the soils ability to properly drain. This will indicate the type of system that will be allowed to be used.

A conventional system is the least expensive, with the At-Grade next and the Mound after more costly after that.

All these other systems are doing is artificially lifting the drain fields higher to meet the 36" rule.

Septic tanks do what is called anaerobic treatment or "without oxygen" plus settles out sludge to prevent it from reaching the drainage field area. Drain field areas and it does not matter the type are called aerobic treatment where oxygen reaches the effluent liquid to oxidize it. The soil then filters the remaining contaminants out.

Typically septic tanks should be pumped every three years or checked as they may not be in need of pumping if not used regularly.

Septic evaluations go through various components of the system to determine any visual evidence of defects.

Some hints to protect your septic are:

  • Have it inspected every 2 - 3 years and have it pumped when when needed to prevent solids from entering the drainfield.

  • Reduce amounts of solids entering the septic tank by reducing the amount of fats and oils down the drain. Compost rather than use the disposal to dispose of food waste.

  • Avoid disposing of hazardous substances down the drains such as solvents, paint, etc.

  • Reduce the volume of water entering the septic system by repairing any fixture leaks and keeping the water softener adjusted properly. Use water saving appliances such as low flow toilets and shower heads.

  • Keep storm water out of the septic. Basement drains and sumps should not empty into the septic system.

  • Keep the bacteria working in the system. Excessive amounts of bleach, disinfectants, pesticides, paint thinners and other common household products can kill the bacteria that make the system work.

  • Protect your drainfield. Avoid driving, parking, burning brushpiles over the drainfield. Take care not to plant deep rooted trees or shrubs near the system.