Pipe from Building to Treatment System

• Must be at least three inches in diameter and constructed of cast iron, ductile iron, PVC Schedule 40 or 80, or SDR 26 PVC
• The slope of the pipe must be no less than 1/8 inch per foot of pipe (1 inch of fall per every 8 feet of pipe)
• A two-way cleanout must be provided between the sewer stub out and the treatment tank. An additional cleanout is required every 100 feet on long runs of pipe and within five feet of any 90-degree bends

Pipe After the Treatment System to Disposal

• Must be at least three inches in diameter, a minimum of five feet in length, and constructed of ASTM 3034, SDR 35 PVC, PVC Schedule 40 or 80
• Must maintain a continuous fall to the disposal system
• There must be at least one foot of fall from the bottom of the outlet device to the bottom of the trench

The flowline of the tank’s inlet device in the first compartment of a two-compartment tank must be at least three inches higher than the flowline of the outlet device.

Inlet and outlet devices must use a “T” branch fitting and have a minimum diameter of three inches.

A laser level will be used to ensure the proper slope has been maintained from the cleanout to the inlet of the treatment tank. The laser will also be used to verify the required three-inch difference between the inlet and outlet devices.

Risers must be installed on each tank within the treatment train, extending at least two inches above grade, with an inside diameter equal to or larger than the inspection or cleanout ports, which must be at least 12 inches in diameter. Risers must be permanently fastened to the tank lid, be watertight, and fitted with removable watertight caps. They must also be protected against unauthorized intrusion.

A secondary plug, cap, or other suitable restraint system must be installed below the riser cap to prevent tank entry if the cap is damaged or removed. This is often referred to as secondary containment.

The required amount of drainfield is based on the total Gallons Per Day (GPD), typically determined by the square footage of living area and/or number of bedrooms in a single-family residence. Sizing may vary depending on the type of dwelling(s) served.

Each excavation must be a minimum of 18 inches wide and not exceed 150 feet in length. Most leaching chambers are two to three feet wide.

The drainfield must have a minimum of twelve inches of cover on the leaching chamber and a maximum depth of five feet.

Multiple excavations must be separated horizontally by at least three feet of undisturbed soil.

The bottom of the excavation must be level to within one inch over every 25 feet of excavation or within three inches over the entire excavation, whichever is less. This will be verified using a laser level.

 Private Water Well

• 50-foot radius to treatment tanks
• 100-foot radius to disposal field (can be reduced to 50 feet if the water well is properly pressure cemented)
• 20 feet to sewer line

Public Water Well

• 50-foot radius to treatment tanks
• 150-foot radius to disposal field
• 20 feet to sewer line

Water Line

• 10-foot radius to treatment tank, sewer line, and disposal field

Foundations, Buildings, Surface Improvements, Property Lines, Swimming Pools, and Other Structures

• 5 feet for tanks and disposal field

Easements

• 1 foot for tanks and disposal field