Conventional Gravity Flow Drainfield
This is a septic system where the effluent from the septic tank gravity flows into the drainfield (absorptive bed or leach field). This type of system requires a minimum of 48 inches of suitable soil before encountering a restrictive rock horizon or groundwater. The natural slope of the property cannot exceed 30%. There is no maintenance contract required.

Pumped Effluent Drainfield
This is a septic system where the effluent from the septic tank is pumped into the drainfield (absorptive bed or leach field) because the drainfield is located at a higher elevation than the septic tank. This type of system requires a minimum of 48 inches of suitable soil before encountering a restrictive rock horizon or groundwater. The natural slope of the property cannot exceed 30%. The negative to this type of system is that the pump may need to be replaced over time. There is no maintenance contract required.

Low Pressure Dose Drainfield
This is a septic system where the effluent from the septic tank is pumped into the drainfield (absorptive bed or leach field) providing equal distribution of the effluent simultaneously throughout the drainfield. This type of system requires a minimum of 24 inches of suitable soil before encountering a restrictive rock horizon and a minimum of 36 inches of suitable soil before encountering groundwater. The natural slope of the property cannot exceed 30%. The negative to this type of system is that the pump may need to be replaced over time. There is no maintenance contract required.

Soil Substitution Drainfield
This is a septic system where the drainfield may be constructed in soils which contain greater than 30% gravel, fractured rock, fissured rock, or other areas of high permeability where septic tank effluent could rapidly reach groundwater without undergoing adequate treatment through soil contact. A soil substitution drainfield is constructed similar to a conventional gravity flow drainfield except that a 2-foot thick soil buffer shall be placed below and all sides of the drainfield excavation. The natural slope of the property cannot exceed 30%. The negative to this type of system is that the substituted soil increases the price of the septic system. There is no maintenance contract required.

Mound Drainfield
This is a septic system where the drainfield is constructed above the native soil surface. A mound drainfield may only be constructed on sites with a minimum of one foot of native soil. However, approval for sites with less than one foot of native soil can be granted by the permitting authority on a case-by-case basis. This type of system requires a minimum of 12 inches of suitable soil before encountering a restrictive rock horizon and a minimum of 24 inches of suitable soil before encountering groundwater. The natural slope of the property cannot exceed 10%. The negative to this type of system is that the pump may need to be replaced over time and that the mound can be an “eye-sore” if constructed too high. There is no maintenance contract required.

Aerobic Treatment Unit with Surface Application
This is a septic system where the effluent from the septic tank is treated and sprayed on the ground like a sprinkler system. Land acceptable for surface application shall have a flat terrain and shall be covered with grasses, evergreen shrubs, bushes, trees, or landscaped beds containing mixed vegetation. There shall be nothing in the surface area within 10 feet of the sprinkler which would interfere with the uniform application of the effluent. The natural slope of the property cannot exceed 15%. The negative to this type of system is that the pump, aerator, and chlorinator may need to be replaced over time. A maintenance contract is required throughout the life of this septic system and some counties require that the system utilize a telephone line to notify the maintenance provider of time of malfunction or failure.

Aerobic Treatment Unit with Drip Irrigation
This is a septic system that may be installed in all classes of soil. The system must be equipped with a filtering device capable of filtering particles larger than 100 microns and that meets the manufacturer’s requirements. The drainfield shall consist of a matrix of small-diameter pressurized lines, buried at least 6 inches deep, and pressure reducing emitters spaced at a minimum of 30-inch intervals. The pressure reducing emitter shall restrict the flow of effluent to a flow rate low enough to ensure equal distribution of effluent throughout the drainfield. This type of system requires a minimum of 6 inches of suitable soil before encountering a restrictive rock horizon and a minimum of 12 inches of suitable soil before encountering groundwater with the use of a chlorinator. The natural slope of the property cannot exceed 30%. The negative to this type of system is that the pump, aerator, and chlorinator may need to be replaced over time. A maintenance contract is required throughout the life of this septic system and some counties require that the system utilize a telephone line to notify the maintenance provider of time of malfunction or failure.