This guide will help the applicant complete the Application for a Sewage System Permit. Information has been provided to assist the applicant with the evaluation of the site and soils, and with the design of the sewage system. The environment inspector does not design a sewage system.
It is the responsibility of the owner or the authorized agent to submit a complete application that includes the designed system exactly as the system is to be installed. Recent changes in legislation now require that all work on a sewage system be completed in accordance with the proposed sewage system as submitted in the application.
Sewage System to serve
Describe the intended use of the structure, i.e., single family dwelling, restaurant, motel, etc. For commercial uses and large systems additional information will be required. Full knowledge of Section 8 of the Building Code is essential for such systems.
State Number Of:
This section refers to the building or structure that will be served by the proposed sewage system.
Total Floor Area m2 (excluding basement)
State total floor area of all building levels in square metres.
Total No. of fixture units
Complete the following chart to determine the total number of fixture units.
Include all fixture units in basement and accessory buildings.
| Fixture | # of Fixture Types | Fixture Units | Total Fixture Units by Type |
| i.e. flush toilet with tank | 3 | 4 | 12 |
| Bathtub (with or without shower) | 1 | ||
| Bidet | 1 | ||
| Dishwasher Domestic | 1 | ||
| Garbage grinder - commercial type | 3 | ||
| Shower drain from 1 head | 1 | ||
| Sink domestic and other small | 1 | ||
| Urinal - wall washout | 1 | ||
| Flush toilets- a:with flush tank b:with direct flush |
4 6 |
||
| Laundry Tubs/Wash Machine | 1 | ||
| Other: | |||
| Total # of Fixture Units | |||
If plumbing fixtures in your building are not listed above, please include the item on application under "Other" and refer to the Ontario Building Code, Chapter 7 for a complete description regarding fixture rating. Include all units when stating the total number of fixtures units.
See Ontario Building Code Table 8.2.1.3.A for complete text
Residential Occupancy
a) 1-bedroom dwelling
750
b) 2-bedroom dwelling
1100
c) 3-bedroom dwelling
1600
d) 4-bedroom dwelling
2000
e) 5-bedroom dwelling
2500
f) dwelling over 200 m2
2500
i) each bedroom over 5
500
ii) A) each 10 m2 (or part thereof over 200 m2 up to 400 m2 3
100
iii) each fixture unit over 20 fixture units
50
Notes for Table 8.2.1.3.A.
1.The occupant load shall be calculated using subsection 3.1.16
2.Where multiple calculations of sewage volume is permitted the calculation resulting the highest flow shall be used in determining the design daily sanitary sewage flow.
3.Total finished area, excluding the area of the finished basement.
b.For all other occupancies, the total design sanitary sewage flow shall be at least the value as stated in column 2 from Table 8.2.1.3.B of the Ontario Building Code.
Example Residential Septic design
For a Square footage Home of 2881 feet or 268 square metres
3 Bedroom Dwelling over 200 square metres 2500 litres
Additional 70 square metres 700 litres
Additional fixture units over 20 925 litres
Total daily design flow rate of 4125 Litres
Soil Type (unified soil Classification) T mins/cm
S.M. Poorly graded sands, 10
silty sand
Laundry room Fixture units
Washing machine 1_
Single wash tub 1_
Kitchen
Double sink 1_
Single sink 1_
Dishwasher 1_
Powder room
Toilet 4
Sink 1_
Master bedroom
Shower 1_
Whirl pool 1_
Toilet 4
Sink 1_
Common Bathroom for bedrooms 2&3
Toilet 4
Bath tub 1_
Sink 1_
Total Fixture Units 38 _
Design Calculations
Septic Tank requirements = design flow X Treatment factor
4125 L X 2 = 8250 litres or 1818 Gallons
It is proposed to install a 2000 gallon septic tank.
Absorption Trenches length of distribution piping
Length of distribution piping = total daily design X percolation time
200
= 4125 L X T of 10
200
= 206.25 metres or 674 feet
It is proposed to install 4 inch perforated pipe in six runs of 115 ft or 35 metres spaced a minimum of 1.7 metres apart
Note: Septic bed must be placed so that the following separation distances are complied with.
5 metres from a structure (17 ft)
15 metres from a drilled well (50ft)
30 metres from a dug well or sand point (100ft)
15 metres from a pond, lake, river or natural spring (50ft)
15 metres from a reservoir (50ft)
3 metres from a property line (10ft)
Material List
690 feet 4 inch perforated drainage tile
690 feet untreated building paper or filter cloth
140 feet 4 inch solid sewer tile
8 - 4 inch 90 degree elbows
3 - 4 inch tee's
1 five hole distribution box
1 Septic Tank 9100 litres (2000 gal)
54 cubic yards of 1 inch stone approximately 76 tons
Typical Septic Bed Installation