Sewage Disposal System
Introduction
The proper treatment and disposal of sewage
is an essential element of our high standard of health and welfare in Ontario.
Many bacterial and viral diseases, which less than a century ago frequently
reached epidemic status, have been drastically reduced or eliminated through
advances in sanitary engineering. Today sewage disposal is not something that
most people living in municipally serviced areas of Caledon often think about.
Public sanitary sewer systems and sewage treatment plants virtually eliminate
the need for public concern.
In
areas without sanitary sewers, sewage disposal is the responsibility of each
property owner. Residential, commercial, and industrial property owners alike
must treat and dispose of sanitary sewage and waste water on their property. To
this end, a properly designed, constructed and maintained on-site private
sewage disposal system will function effectively and safely for many years. A
poorly designed or constructed system, or one that is not properly maintained
can be dangerous to health, damage the environment and be costly to repair.
The
purpose of this section of the website is to familiarize you with the operation
and maintenance of your on-site sewage disposal system. Also, provided are the
requirements for permit application and approval if you are installing a new
system, or replacing or repairing an existing system.
Should
you have queries which are not addressed here, please contact us.
Town
of Caledon Building and Support Services Section
6311 Old Church Road
Caledon, Ontario
L7C 1J6
Phone:
(905) 584-2272
Toll-free: 1 (888) 225-3366
Fax: (905) 584-4325
Please
select the On-site Sewage Disposal Systems section you are interested in:
·
The Law Relating to On-site Private Sewage Disposal
·
Fundamentals of On-site Private Sewage Disposal
·
Approval Process
·
Types of Private Sewage Disposal Systems
·
Care and Maintenance of a Sewage System
·
Problems
The Law Relating to
On-site Private Sewage Disposal
The standards for on-site sewage disposal systems discharging 10,000 litres and
less are prescribed by the Building Code Act and the Ontario Building
Code.
In the Town of Caledon, the installation requirements listed in the Ontario
Building Code are administered by the Building and Support Services Section.
The Building Code Act requires that any new development serviced by
on-site sewage disposal, or any alteration to an existing system or building
that may impact on an existing on-site sewage disposal system be undertaken
only with a permit issued by the Chief Building Official. This includes
additions to your home, accessory buildings, and swimming pools. Aside from the
legal requirement to do so, it is in your best interest to contact the Building
and Support Services Section to discuss your building plans because your
construction project may be influenced by the location of your sewage disposal
system. The Ontario Building Code requires a sewage system to be completed and
operational prior to occupancy of any building.
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Fundamentals of
On-site Private Sewage Disposal
For the purpose of
private sewage disposal, sanitary sewage includes liquid or water borne waste
of industrial or commercial origin, or of domestic origin, including toilet,
shower, tub, laundry or kitchen waste. Other sources of water such as rain
water leaders, downspouts, eavestroughs, weeping tiles, and sump pump
discharges are considered to be storm sewage and must not be discharged to a
private sewage disposal system.
Sewage created
within your home is discharged into a tank at the exterior. After treatment in
the tank the liquid portion known as 'effluent' is discharged to a disposal,
leaching, or tile bed where additional treatment and final disposal occurs.
This is explained in more detail later in this booklet.
The successful
operation of an on-site sewage disposal system depends on the volume of sewage
produced and the suitability of the soil to absorb the effluent (liquid waste).
The daily sewage
flow from a house or dwelling is estimated according to various factors,
including the number of bedrooms, the side of dwelling, the flow from the
plumbing fixtures, and the type of soil located on site. In the case of
industrial or commercial development the daily flow is determined from the use.
The design
criteria for on site sewage disposal systems is found in the Ontario
Building Code. All installers (contractors) employed in the business of
installation or design of on-site sewage disposal systems in the province of
Ontario must be licensed with the Ministry of Municipal Affairs and Housing. In
certain circumstances, a professional consulting engineer must be hired by the
property owner or developer to design the sewage system.
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Approval Process
1. Size
the System
Following a calculation of the sanitary sewage volume (daily design flow) of
the building, a soils analysis is required. The analysis, completed by a
geotechnical engineer will show the percolation capacity of the soil (known as
the percolation time or T-time). Using the daily design flow, soils analysis,
and the requirements listed in the Ontario Building Code, a design can be
completed.
2. Submit
your Design
The design to be submitted for permit review and approval is required to
include the following.
o
2 copies of a site plan (scaled map) showing the
sewage system, any structures on the property, wells, watercourses, property
lines, etc. and measurements to those features
o
the soils analysis showing the T-time
o
a fully completed 'Application Form and Certificate
of Approval For a Sewage System'. The application form can be completed by the
property owner or an authorized agent acting on behalf of the owner.
3. Starting
Installation
If the design is acceptable, a certificate of approval is issued allowing
construction of the sewage system to begin. If the sewage system is being
constructed to service a new building or building addition, a permit can now be
applied for.
4. Inspection
Before covering any part of a sewage system, an inspection and approval is to
be obtained from a Town of Caledon Building Inspector. As an example, the
following is a list of the sewage system components required to be inspected in
a Class 4 system: the sewage system area; the contact area as used in a raised
system; the septic tank(s); pump chamber, pumps, and pump controls/alarms;
leaching bed piping; and a final grading inspection.
5. Need
Help or Information?
Building and Support Services Section staff are available at any time during
the design, review, approval, or installation of the sewage system to provide
information and assistance.
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Types of Private Sewage Disposal
Systems
There are several varieties of private sewage
disposal systems in common use in Ontario. This section is to provide sewage
system owners with the basic understanding of the most common type of sewage
system used and how it operates. To determine the type of sewage system on your
property, please refer to your certificate of approval.
Primary Sewage Treatment
An on site private sewage disposal system generally
consists of two parts; a septic tank or treatment unit which receives the
untreated sewage from the house or building, and a leaching or disposal bed
which introduces the liquid portion of the sewage into the soil.
Class 4 System
The Class 4 system has the widest range of
applications and can be configured as an in ground or raised leaching bed or
filter bed system. The operation of these variations are as follows:
1. Septic
Tank
The main function of the septic tank is to remove solids and grease from the
raw sewage that would otherwise plug the leaching bed. Suspended solids in the
raw sewage are settled out in the first compartment of the septic tank and the
liquid portion of the sewage flows through to the second compartment. Anaerobic
(without oxygen) bacterial action breaks down much of the solid matter to
liquids and gases. If the septic tank is working and maintained properly, only
liquid waste should be discharged to the leaching bed system.
Sludge (settled solids) and scum (floatables) accumulate over time in the
septic tank and must be periodically removed and properly disposed of to
safeguard efficient operation of the septic tank. You should contact a licensed
contractor by consulting your yellow pages under "septic tanks" and
have your system inspected at least once every two years.
The bacterial action in a septic tank produces odours. The septic tank, however
is normally vented back through the house sanitary drainage venting system to
open air at the plumbing stacks.
Septic tanks are sized according to the daily design flow of the building. A
septic tank must have a capacity of double the daily design flow for
residential occupancies and triple the daily design flow for non-residential.
Despite the daily design flow, septic tanks can have a capacity of no less than
3600 litres.
2. Leaching
Bed
Installation of leaching beds in native soils are allowable only if ground
conditions permit (see raised leaching beds). The leaching bed is comprised of
a number of lengths of perforated piping placed in carefully prepared trenches.
The liquid sewage effluent passes through the pipe into the soil where further
treatment by aerobic (with oxygen) bacteria takes place.
3. Raised
Leaching Bed
In areas with high groundwater conditions, shallow bedrock, or poorly pervious
natural soils, porous soils must be imported to construct a raised leaching
bed. Soil must also be imported to construct a mantle which extends from the
raised leaching bed piping to a distance of 15m in any direction which sewage
is likely to flow after it has moved through the raised leaching bed. The
maximum slope off the sides of a raised leaching bed is 4 units horizontally to
1 unit vertically. The distances to property lines must also be increased if a
raised leaching bed is used.
4. Filter
Beds
A filter bed consists of distribution piping placed on a continuous layer of
stone above an approved sand filter medium. A filter bed concentrates the
application of sewage effluent in a smaller area than a trenched leaching bed.
Consequently, the need for a sound mantle around the filter to absorb effluent
as it moves through the filter bed is critical.
5. Pumps,
Siphons, and Distribution Boxes
When the total length of the leaching bed is 150 metres or more a pump or
siphon must be installed in a separate tank. The purpose of the pump or siphon
is to ensure that effluent reaches all parts of the leaching bed. A pump or
siphon also permits the leaching bed to rest between doses and assists in
preventing the leaching bed from freezing during extremely cold weather. An
effluent pump may also be required for any leaching bed which is higher in
elevation than the septic tank or treatment unit. A good quality effluent pump
will last for many years, but as with all mechanical devices, it will
eventually fail. A high level alarm should be installed to warn of a pump
failure.
A distribution box may be used to assist with balancing the flow of effluent to
each length of the leaching bed. If a distribution box is used, it should be
placed on a compacted foundation to ensure that it is kept level. A split
header may also be used to distribute effluent. A split header is a secondary
header connecting to the main header of the leaching bed. The split header
helps distribute effluent to the entire main header.
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Care and Maintenance
of a Sewage System
A sewage system
should, with proper care and maintenance, provide many years of service. There
are, however, some things which you, the sewage system owner, should be aware
of that will help the system to function.
The area over the
leaching bed should have a good cover of grass, good ventilation and adequate
sunlight. When landscaping, remember not to add soil to the leaching bed.
Vegetable gardens, particularly root crops are not recommended over a leaching
bed. Trees and shrubs should not be planted in the immediate vicinity of the
leaching bed as root proliferation can disrupt and block the leaching bed
piping. In addition, structures such as patios, sundecks, and tool sheds cannot
be erected over your leaching bed.
Water usage should
be kept to a minimum. Excessive waste water taxes the ability of the leaching
bed to dispose of liquid sewage and could flush solids from the septic tank to
the leaching bed. An automatic irrigation system should not be installed on or
around leaching beds. Surface water should also be diverted away from leaching
beds. These two factors can saturate a leaching bed and cause the system to
malfunction.
Moderate use of
household drain solvents, cleaners, or disinfectants should not interfere with
the operation of the sewage disposal system. Indiscriminate use, however, may
cause problems. Other chemicals such as paint thinners, pesticides, and
herbicides should never be poured down the drain. These chemicals will
contaminate ground water. Vehicular traffic should not be allowed over the
leaching bed. Vehicles may cause soil compaction and damage to the piping.
Your septic tank
should be inspected every 2 years and the tank pumped out when necessary
(approximately every 4 years). Failure to pump out a septic tank will allow
sludge or scum to be carried into the leaching bed piping. The final result of
not maintaining your septic tank will be failure of the system. Regular
maintenance of the septic tank is well worth the effort.
WARNING!
Under no circumstances
should anyone enter a septic tank. Noxious gases which are heavier than air
remain in the tank after the top is removed, and have caused death to both the
original victim and to those who have attempted to rescue the first victim.
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Problems
Should
you experience a problem with your on site sewage disposal system, such as
sewage effluent discharging from the leaching bed to the surface of the ground,
you must notify the Building and Support Services Section immediately.
Arrangements with a licensed on site sewage system installer must be made to
have your system repaired. As an owner/operator of a sewage system you are
responsible by law to properly maintain and operate your system. The Building
Code Act considers a malfunctioning system to be an unsafe condition.
Please
direct any questions regarding on-site sewage disposal systems in the Town of
Caledon to:
Town
of Caledon Building and Support Services Section
6311 Old Church Road
Caledon, Ontario
L7C 1J6
Phone:
(905) 584-2272
Toll-free: 1 (888) 225-3366
Fax: (905) 584-4325
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