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903.1 Mound Dimensions and Design

Private Sewage Disposal Code 2012 of South Holland, IL > 9 Mound Systems > 903 System Design > 903.1 Mound Dimensions and Design

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For one- and two-family dwellings and other buildings with estimated waste water flows less than 600 gallons (2271 L) per day, the mound dimensions shall be determined in accordance with this section or Tables 903.1(1) through 903.1(12). Dimensions and corresponding letter designations listed in the tables and referenced in this section are shown in Appendix A, Figures A-6 through A-10. For buildings with estimated waste water flows exceeding 600 gallons (2271 L) per day, the mound shall be designed in accordance with this section. Daily waste water flow shall be estimated as 150 gallons (568 L) per day per bedroom for one- and two-family dwellings. For other buildings the total daily waste water flow shall be determined in accordance with Table 802.7.2.

TABLE 903.1(1)
DESIGN CRITERIA FOR A MOUND FOR A ONE-BEDROOM HOME ON A 0- TO 6-PERCENT SLOPE WITH LOADING RATES OF 150 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL
DESIGN PARAMETER		SLOPE (percent)
DESIGN PARAMETER		0	2	4	6
A	Trench width, feet	3	3	3	3
B	Trench length, feet Number of trenches	42 1	42 1	42 1	42 1
D	Mound height, inches	12	12	12	12
F	Mound height, inches	9	9	9	9
G	Mound height, inches	12	12	12	12
H	Mound height, inches	18	18	18	18
I	Mound width, feet^a	15	15	15	15
J	Mound width, feet^a	11	8	8	8
K	Mound length, feet	10	10	10	10
L	Mound length, feet	62	62	62	62
P	Distribution pipe length, feet	20	20	20	20
	Distribution pipe diameter, inches	1	1	1	1
	Number of holes per distribution pipe^b	9	9	9	9
	Hole spacing, inches^b	30	30	30	30
	Hole diameter, inches^b	0.25	0.25	0.25	0.25
W	Mound width, feet	25	26	26	26

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L.

Additional width to obtain required basal area.
Last hole is located at the end of the distribution pipe, which is 15 inches from the other hole.

TABLE 903.1 (2)
DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE WITH LOADING RATES OF 300 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL
DESIGN PARAMETER		SLOPE (percent)
DESIGN PARAMETER		0	2	4	6
A	Trench width, feet	3	3	3	3
B	Trench length, feet Number of trenches	42 2	42 2	42 2	42 2
C	Trench spacing, feet	15	15	15	15
D	Mound height, inches	12	12	12	12
E	Mound height, inches	12	17	25	25
F	Mound height, inches	9	9	9	9
G	Mound height, inches	12	12	12	12
H	Mound height, inches	18	18	18	18
I	Mound width, feet^a	12	20	20	20
J	Mound width, feet	12	8	8	8
K	Mound length, feet	10	10	10	10
L	Mound length, feet	62	62	62	62
P	Distribution pipe length, feet	20	20	20	20
	Distribution pipe diameter, inches	1	1	1	1
	Number of holes per distribution pipes^b	9	9	9	9
	Hole spacing, inches^b	30	30	30	30
	Hole diameter, inches	0.25	0.25	0.25	0.25
R	Manifold length, feet Manifold diameter, inches^c	15 2	15 2	15 2	15 2
W	Mound width, feet	42	46	46	46

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L.

Additional width to obtain required basal area.
Last hole is located at the end of the distribution pipe, which is 15 inches from the other hole.
Diameter dependent on the size of pipe from pump and inlet position.

TABLE 903.1(3)
DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE WITH LOADING RATES OF 450 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL
DESIGN PARAMETER		SLOPE (percent)
DESIGN PARAMETER		0	2	4	6
A	Trench width, feet	3	3	3	3
B	Trench length, feet Number of trenches	63 2	63 2	63 2	63 2
C	Trench spacing, feet	15	15	15	15
D	Mound height, inches	12	12	12	12
E	Mound height, inches	12	17	20	25
F	Mound height, inches	9	9	9	9
G	Mound height, inches	12	12	12	12
H	Mound height, inches	18	18	18	18
I	Mound width, feet^a	12	20	20	20
J	Mound width, feet^a	12	8	8	8
K	Mound length, feet	10	10	10	10
L	Mound length, feet	62	62	62	62
P	Distribution pipe length, feet Distribution pipe diameter, inches Number of holes per distribution pipe^b Hole spacing^b, inches Hole diameter, inches	31 1¹/₄ 13 30 0.25	31 1¹/₄ 13 30 0.25	31 1¹/₄13 30 0.25	31 1¹/₄13 30 0.25
R	Manifold length, feet Manifold diameter, inches^c	15 2	15 2	15 2	15 2
W	Mound width, feet	42	46	46	46

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L.

Additional width to obtain required basal area.
First hole is located 12 inches from the manifold.
Diameter dependent on the size of pipe from pump and inlet position.

TABLE 903.1(4)
DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 6-PERCENT SLOPE WITH LOADING RATES OF 600 GALLONS PER DAY FOR SLOWLY PERMEABLE SOIL
DESIGN PARAMETER		SLOPE (percent)
DESIGN PARAMETER		0	2	4	6
A	Trench width, feet	3	3	3	3
B	Trench length, feet Number of trenches	56 3	56 3	56 3	56 3
C	Trench spacing, feet	15	15	15	15
D	Mound height, inches	12	12	12	12
E	Mound height, inches	12	20	28	36
F	Mound height, inches	9	9	9	9
G	Mound height, inches	12	12	12	12
H	Mound height, inches	24	24	24	24
I	Mound width, feet^a	12	20	20	20
J	Mound width, feet^a	12	8	8	8
K	Mound length, feet	12	12	12	14
L	Mound length, feet	80	80	80	84
P	Distribution pipe length, feet Distribution pipe diameter, inches Number of holes per distribution pipe^b Hole spacing, inches^b Hole diameter, inches	27.5 1¹/₄ 12 30 0.25	27.5 1¹/₄ 12 30 0.25	27.5 1¹/₄ 12 30 0.25	27.5 1¹/₄ 12 30 0.25
R	Manifold length, feet Manifold diameter, inches^c	30 2	30 2	30 2	30 2
W	Mound width, feet	57	61	61	61

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L.

Additional width to obtain required basal area.
Last hole is located at the end of the distribution pipe, which is 15 inches from the previous hole.
Diameter dependent on the size of pipe from pump and inlet position.

TABLE 903.1(5)
DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 150 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		3 to 60				3 to less than 30
		0	2	4	6	8	10^a	12^a
A	Bed width, feet^b	10	10	10	10	10	10	10
B	Bed length, feet	13	13	13	13	13	13	13
D	Mound height, inches	24	24	24	24	24	24	24
E	Mound height, inches	24	26	29	31	34	36	38
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	12	13	14	17	18	21	26
J	Mound width, feet	12	11	10	10	9	9	9
K	Mound length, feet	12	12	12	13	13	13	15
L	Mound length, feet	37	37	37	39	39	39	43
P	Distribution pipe length, feet^c Distribution pipe diameter, inches Number of distribution pipes	12.5 1 6	12.5 1 6	12.5 1 6	12.5 1 6	12.5 1 6	12.5 1 6	12.5 1 6
R	Manifold length, feet Manifold diameter, inches^c	6 2	6 2	6 2	6 2	6 2	6 2	6 2
S	Distribution pipe spacing, feet	3	3	3	3	3	3	3
	Number of holes per distribution pipe^d	6	6	6	6	6	6	6
	Hole spacing, inches^d	30	30	30	30	30	30	30
	Hole diameter, inches	0.25	0.25	0.25	0.25	0.25	0.25	0.25
W	Mound width, feet	34	34	34	37	37	41	45

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

On sites with a 10- to 12-percent slope, the fill depth (D) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease E [downslope fill depth, feet (mm)].
Bed widths shall not be limited.
Use a manifold with distribution pipes on only one side.
Last hole is located at the end of the distribution pipe, which is 15 inches from the previous hole.

TABLE 903.1(6)
DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 300 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		3 to 60			3 to less than 30
		0	2	4	6	8	10^a	12^a
A	Bed width, feet^b	10	10	10	10	10	10	10
B	Bed length, feet	25	25	25	25	25	25	25
D	Mound height, inches	24	24	24	24	24	24	24
E	Mound height, inches	24	26	29	31	34	36	38
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	12	13	14	17	18	21	26
J	Mound width, feet	12	11	10	10	9	9	9
K	Mound length, feet	12	12	12	13	13	13	15
L	Mound length, feet	49	49	49	51	51	51	55
P	Distribution pipe length, feet^c Distribution pipe diameter, inches Number of distribution pipes	12 1 6	12 1 6	12 1 6	12 1 6	12 1 6	12 1 6	12 1 6
R	Manifold length, feet Manifold diameter, inches	6 2	6 2	6 2	6 2	6 2	6 2	6 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^d Hole spacing, inches^d Hole diameter, inches	3 5 30 0.25	3 5 30 0.25	3 5 30 0.25	3 5 30 0.25	3 5 30 0.25	3 5 30 0.25	3 5 30 0.25
W	Mound width, feet	34	34	34	37	37	41	45

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

On sites with a 10- to 12-percent slope, the fill depth (D) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease E [downslope fill depth, feet (mm)].
Bed widths shall not be limited.
This design is based on a manifold with distribution pipes on both sides. An alternative design basis is 24-foot distribution pipes, with manifold at the end.
Last hole is located 9 inches from the end of the distribution pipe.

TABLE 903.1(7)
DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 450 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		3 to 60		3 to less than 30
		0	2	4	6	8	10^a	12^a
A	Bed width, feet^b	10	10	10	10	10	10	10
B	Bed length, feet	38	38	38	38	38	38	38
D	Mound height, inches	24	24	24	24	24	24	24
E	Mound height, inches	24	26	29	31	34	36	38
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	12	13	14	17	18	21	26
J	Mound width, feet	12	11	10	10	9	9	9
K	Mound length, feet	12	12	12	13	13	13	15
L	Mound length, feet	62	62	62	64	64	64	68
P	Distribution pipe length, feet^c Distribution pipe diameter, inches Number of distribution pipes	18.5 1 6	18.5 1 6	18.5 1 6	18.5 1 6	18.5 1 6	18.5 1 6	18.5 1 6
R	Manifold length, feet Manifold diameter, inches	6 2	6 2	6 2	6 2	6 2	6 2	6 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^d Hole spacing, inches^d Hole diameter, inches	3 8 30 0.25	3 8 30 0.25	3 8 30 0.25	3 8 30 0.25	3 8 30 0.25	3 8 30 0.25	3 8 30 0.25
W	Mound width, feet	34	34	34	37	37	41	45

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

On sites with a 10- to 12-percent slope, the fill depth (D) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease E [downslope fill depth, feet (mm)].
Bed widths shall not be limited.
Use a manifold with distribution pipes on only one side.
Last hole is located at the end of the distribution pipe, which is 27 inches from the previous hole.

TABLE 903.1(8)
DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 600 GALLONS PER DAY FOR SHALLOW PERMEABLE SOIL OVER CREVICED BEDROCK
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		3 to 60				3 to less than 30
		0	2	4	6	8	10^a	12^a
A	Bed width, feet^b	10	10	10	10	10	10	10
B	Bed length, feet	50	50	50	50	50	50	50
D	Mound height, inches	24	24	24	24	24	24	24
E	Mound height, inches	24	26	29	31	34	36	38
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	12	13	14	17	18	21	26
J	Mound width, feet	12	11	10	10	9	9	9
K	Mound length, feet	12	12	12	13	13	13	15
L	Mound length, feet	74	74	74	76	76	76	78
P	Distribution pipe length, feet^c Distribution pipe diameter, inches Number of distribution pipes	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6
R	Manifold length, feet Manifold diameter, inches	6 2	6 2	6 2	6 2	6 2	6 2	6 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^d Hole spacing, inches^d Hole diameter, inches	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25
W	Mound width, feet	34	34	34	37	37	41	45

For SI: 1 inch 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

On sites with a 10- to 12-percent slope, the fill depth (D) shall be reduced to a minimum of 1.5 feet or the bed width shall be reduced to decrease E [downslope fill depth, feet (mm)].
Bed widths shall not be limited.
Use a manifold with distribution pipes on only one side.
Last hole is located 9 inches from the end of the distribution pipe.

TABLE 903.1(9)
DESIGN CRITERIA FOR A ONE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 150 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		0 to 60				0 to less than 30
		0	2	4	6	8	10	12
A	Bed width, feet	4	4	4	4	4	4	4
B	Bed length, feet	32	32	32	32	32	32	32
D	Mound height, inches	12	12	12	12	12	12	12
E	Mound height, inches	12	13	14	14	16	17	18
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	9	10	11	12	13	14	15
J	Mound width, feet	9	9	8	8	7	7	6
K	Mound length, feet	10	10	10	10	10	11	11
L	Mound length, feet	52	52	52	52	52	53	53
P	Distribution pipe length	15.5	15.5	15.5	15.5	15.5	15.5	15.5
	Distribution pipe diameter, inches	1	1	1	1	1	1	1
	Number of distribution pipes	2	2	2	2	2	2	2
	Number of holes per distribution pipe^a	7	7	7	7	7	7	7
	Hole spacing, inches^a	30	30	30	30	30	30	30
	Hole diameter, inches	0.25	0.25	0.25	0.25	0.25	0.25	0.25
W	Mound width, feet	22	23	23	24	24	25	25

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

Last hole is located at the end of the distribution pipe, which is 21 inches from the previous hole.

TABLE 903.1(10)
DESIGN CRITERIA FOR A TWO-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 300 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		0 to 60				0 to less than 30
		0	2	4	6	8	10	12
A	Bed width, feet	6	6	6	6	6	6	6
B	Bed length, feet	42	42	42	42	42	42	42
D	Mound height, inches	12	12	12	12	12	12	12
E	Mound height, inches	12	13	14	17	18	19	22
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	9	10	11	12	13	15	16
J	Mound width, feet	9	9	8	8	7	7	6
K	Mound length, feet	10	10	10	10	10	11	11
L	Mound length, feet	62	62	62	62	62	64	64
P	Distribution pipe length, feet^a Distribution pipe diameter, inches Number of distribution pipes	20 1 4	20 1 4	20 1 4	20 1 4	20 1 4	20 1 4	20 1 4
R	Manifold length, feet Manifold diameter, inches	3 2	3 2	3 2	3 2	3 2	3 2	3 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^b Hole spacing, inches^b Hole diameter, inches	3 9 30 0.25	3 9 30 0.25	3 9 30 0.25	3 9 30 0.25	3 9 30 0.25	3 9 30 0.25	3 9 30 0.25
W	Mound width, feet	24	25	25	26	26	28	29

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

Use a manifold with distribution pipes only on one side.
Last hole is located at the end of the distribution pipe, which is 15 inches from the previous hole.

TABLE 903.1(11)
DESIGN CRITERIA FOR A THREE-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 450 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		0 to 60				0 to less than 30
		0	2	4	6	8	10	12
A	Bed width, feet	8	8	8	8	8	8	8
B	Bed length, feet	47	47	47	47	47	47	47
D	Mound height, inches	12	12	12	12	12	12	12
E	Mound height, inches	12	12	16	18	19	22	24
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	9	11	12	13	15	17	18
J	Mound width, feet	9	9	8	8	7	7	6
K	Mound length, feet	10	10	10	10	10	11	12
L	Mound length, feet	67	67	67	67	69	69	71
P	Distribution pipe length, feet Distribution pipe diameter, inches Number of distribution pipes	23 1 6	23 1 6	23 1 6	23 1 6	23 1 6	23 1 6	23 1 6
R	Manifold length, feet Manifold diameter, inches	64 2	64 2	64 2	64 2	64 2	64 2	64 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^a Hole spacing, inches^a Hole diameter, inches	32 10 30 0.25	32 10 30 0.25	32 10 30 0.25	32 10 30 0.25	32 10 30 0.25	32 10 30 0.25	32 10 30 0.25
W	Mound width, feet	26	28	28	29	30	32	32

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1 minute per inch = 2.4 s/mm.

Last hole is located at the end of the distribution pipe, which is 21 inches from the previous hole.

TABLE 903.1(12)
DESIGN CRITERIA FOR A FOUR-BEDROOM HOME FOR A MOUND ON A 0- TO 12-PERCENT SLOPE WITH LOADING RATES OF 600 GALLONS PER DAY FOR PERMEABLE SOIL WITH A HIGH WATER TABLE
DESIGN PARAMETER		PERCOLATION RATE (minutes per inch) SLOPE (percent)
		0 to 60				0 to less than 30
		0	2	4	6	8	10	12
A	Bed width, feet	10	10	10	10	10	10	10
B	Bed length, feet	50	50	50	50	50	50	50
D	Mound height, inches	12	12	12	12	12	12	12
E	Mound height, inches	12	14	17	19	22	24	26
F	Mound height, inches	9	9	9	9	9	9	9
G	Mound height, inches	12	12	12	12	12	12	12
H	Mound height, inches	18	18	18	18	18	18	18
I	Mound width, feet	9	11	13	14	17	18	19
J	Mound width, feet	9	9	8	8	7	7	6
K	Mound length, feet	10	10	10	10	11	11	12
L	Mound length, feet	70	70	70	70	72	72	74
P	Distribution pipe length, feet Distribution pipe diameter, inches Number of distribution pipes	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6	24.5 1 6
R	Manifold length, feet Manifold diameter, inches	6 2	6 2	6 2	6 2	6 2	6 2	6 2
S	Distribution pipe spacing, feet Number of holes per distribution pipe^a Hole spacing, inches^a Hole diameter, inches	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25	3 10 30 0.25
W	Mound width, feet	28	29	31	32	34	35	36