§ 57-22. Disposal of effluent.

A. 

Disposal of septic tank effluent may be by means of leaching cesspools or leaching trenches installed with tile. The minimum required sizes of such systems for various types of soil are listed below:

(1) 

None of these systems shall be laid out in groundwater.

(2) 

Class A soil is considered as rapid-seepage soil (course sand or gravel).

(3) 

Class B soil is considered as medium-seepage soil (fine sand or light sandy loam).

(4) 

Class C soil is considered as slow-seepage soil (clay with some sand or gravel, not for very tight clay soils). In case of doubt as to proper classification of soil, final decision shall be based on the results of soil tests, as described later.

Leaching Cesspools
Type of Soil	Number of Families	Number of Cesspools	Diameter (feet)	Depth Below Inlet (feet)
Class A Soil	1	1	5	5
	2	1	8	6
	3	2	6	6
Class B Soil		1	6	7
		2	6	7
		2	8	8
Class C Soil		2	6	7
		2	9	8
		3	9	8

B. 

Cesspools shall be at least 15 feet apart. They shall not be built below groundwater.

Leaching Trenches Linear feet of leaching trenches 2 feet wide
Number of Families	Number of Bedrooms	Class A Soil	Class B Soil	Class C Soil
1	2	100	120	150
1	3 to 4	120	150 to 175	200
2	4 to 5	120	175 to 200	300
3		150	225	350

(1) 

Tile shall be either unglazed drain tile, at least four inches in diameter, laid with open joints, of four-inch perforated pipe, in trenches about 24 inches wide. Tile shall be laid in the upper one-third (1/3) of a layer of screened gravel or crushed stone about 18 inches deep and shall be covered with a protective layer of thirty-pound asphalt paper or of salt hay.

(2) 

Tile lines shall ordinarily be laid on a grade not exceeding two to four inches per 100 feet. Spacing between trenches for tile lines shall be at least three times the width of the trench. Better distribution is secured in tile fields by using siphondosing apparatus to apply the septic tank effluent.

(3) 

The minimum number of square feet of absorptive area for leaching trenches filled with gravel or broken stone shall be as follows, the absorptive area being calculated as the bottom area of the trench:

Square Feet of Bottom Area
Number of Families	Number of Bedrooms	Class A Soil	Class B Soil	Class C Soil
1	2	200	240	300
1	3 to 4	240	300 to 350	350
2	4 to 5	240	350 to 400	600
3		300	450	900