SEWERAGE HOLDING TANKS
1. What is a “Holding Tank”?
A holding tank is a large container that is used to collect and temporarily store sewage from a
home or building. The sewage is removed and transported to an approved location for disposal.
Holding tanks are used when it is not possible to install a sewage disposal system on a property or
connect to a community sewer system.
A person must not install, repair, or alter a holding tank unless they hold a permit issued by an
Environmental Health Officer. Applications for a holding tank permit are evaluated on a
case-by-case basis. Prior to issuing a permit, the Environmental Health Officer must be satisfied
that the use of a holding tank will be adequate to deal with the sewage generated at a particular
site and that it is unlikely to cause or contribute to a health hazard.
For specific information about the design, siting, and installation of holding tanks see our
“Holding Tank Planning and Installation Guidelines”
To find more information and a copy of the Guidelines go to: www.interiorhealth.ca under Your
Environment – Healthy Built Environment
2. How do I apply for a Holding Tank Permit?
Applicants (owner of the property or someone acting on their behalf) must submit the following
information, along with a $400 application fee, to the local Health Protection office:
a. A completed “Holding Tank Permit Application”. Find the holding tank application form at:
www.interiorhealth.ca under Your Environment – Healthy Built Environment
b. Supporting documentation (e.g. design plans, specifications, site plan, maintenance plan)
described in the “Holding Tank
Planning and Installation Guidelines”. To find more information and a copy of the Guidelines go to:
www.interiorhealth.ca under Your Environment – Healthy Built Environment
Note: Local or regional governments may have bylaws in effect which prohibit or regulate the
construction of a sewage holding tank. In such cases, the more restrictive requirements for the
holding tank will apply.
c. Any other information, as requested by an Environmental Health Officer.
3. What is the application process?
Upon receipt of payment and a completed application package, the Environmental Health Officer will
review the submitted information. A “permit to construct” may be issued if the reviewer is
satisfied that the holding tank is adequate to deal with the domestic sewage originating from the
structure and that the use of the holding tank will not, if the maintenance plan is followed, cause
a health hazard.
Note: Incomplete applications will be returned to the applicant and the review process will be
halted until a complete application is received.
4. When can I start using the Holding Tank?
Once the installation of a holding tank has been completed, the applicant must submit a “Holding
Tank Letter of Certification” and all supporting documents to the local Environmental Health
Officer. A holding tank must not be used until this form has been accepted by the Health
Authority. To find more information and the Letter of Certification form go to:
www.interiorhealth.ca under Your Environment – Healthy Built Environment.
HOLDING TANK PLANNING & INSTALLATION GUIDELINES
Under no circumstances is sewage from a holding tank to be discharged onto the surface of the
ground or into groundwater or surface waters.
TABLE OF CONTENTS
A. General Information ………………………………………………………………………………………………. 2
1. What is a “Holding Tank”? ……………………………………………………………………………….. 2
2. How do I apply for a Holding Tank Permit?…………………………………………………………. 2
3. What happens next?……………………………………………………………………………………….10
4. When can I start using the Holding Tank? ………………………………………………………….10
B. Holding Tank Specifications ……………………………………………………………………………………..11
1. Holding Tank Capacity…………………………………………………………………………………….11
2. Setback Distances (minimum) ………………………………………………………………………….12
3. Construction and Installation ……………………………………………………………………………12
4. Alarm……………………………………………………………………………………………………………14
5. Maintenance Plan…………………………………………………………………………………………..15
6. Resources …………………………………………………………………………………………………….15
APPENDIX A – EXAMPLE OF A SITE PLAN ……………………………………………………………..16
APPENDIX B – TANK MARKING ……………………………………………………………………………..17
A. GENERAL INFORMATION
1. WHAT IS A “HOLDING TANK”?
A holding tank is a large watertight vessel that allows for the collection and temporary storage of
sewage effluent from a residence or building for future removal and transport to an approved
treatment and disposal site.
Holding tanks may be constructed of a variety of materials. Tanks can be prefabricated or they can
be constructed (engineered) in place.
Tanks that are prefabricated must meet the current CAN/CSA B66 standard for design, material, and
manufacturing requirements for prefabricated septic tanks and sewage holding tanks. See Part B –
Holding Tank Guidelines – Construction and Installation for specifics. Tanks constructed in place
must be overseen by an engineer. Proper sizing of tanks will vary depending on intended usage.
See Part B1, Table 1: Minimum Holding Tank Capacities based on Estimated Daily Design Flow for
specifics.
See Section B “Holding Tank Guidelines” for specific information about the design, siting, and
installation of holding tanks.
Improper use and/or maintenance of holding tanks may lead to raw sewage discharges onto the ground
and/or into water bodies, presenting significant health hazards to the public. To ensure that
sewage holding tanks do not cause or contribute to a public health hazard, they are regulated under
Section 4 and 5 of the B.C. Sewerage System Regulation (B.C. Reg 326/2004).
A person must not install, repair, or alter a holding tank unless they hold a construction permit
issued by an Environmental Health Officer, in accordance with the Sewerage System Regulation.
Applications for a holding tank permit are evaluated on a case-by-case basis. However, prior to
issuing a construction permit, the Environmental Health Officer must be satisfied that the use of a
holding tank will be adequate to deal with the domestic sewage generated at a particular site and
that it will not cause or contribute to a health hazard.
Note: Proposed subdivisions must still meet the requirements of the B.C. Subdivision Regulations
(B.C. Reg. 262/70).
2. HOW DO I APPLY FOR A HOLDING TANK PERMIT?
Submit the following information along with a $400 permit application fee to the local
Environmental Health Officer:
A completed “Holding Tank Permit Application”. Include information about the manufacturer and
construction Material. See Section B3 – Construction and Installation for more information.
Note:
Local or regional governments may have bylaws which prohibit or regulate the construction of a
sewage holding tank. In such cases, the more restrictive requirements for the holding tank will
apply.
Holding tank plans and specifications prepared and provided by an authorized person.
Authorized persons include, but may not be limited to, a Registered Onsite Wastewater Professional
(ROWP), or a BC Professional Engineer who has self-declared with APEGBC. See the B.C. Sewerage
System Regulation for more information and Section B3 – Construction and Installation.
Site plan showing the location of the proposed holding tank in relation to (see Appendix A –
Example of a Site Plan):
buildings (with labels),
surface water bodies (lakes, rivers, streams, creeks, etc.),
drinking water source(s) and water lines,
property boundaries with separation distances clearly marked. A surveyor is not required or
recommended,
proposed Maintenance Plan for the holding tank (see Section B6: Maintenance Plan), and
any other information requested by the Environmental Health Officer
Note – Due to differing holding tank site locations each application is assessed on its own merits.
Information requested by the Environmental Health Officer during the application process may
differ from one location to another.
3. WHAT HAPPENS NEXT?
With receipt of payment and a complete application package, the Environmental Health Officer may
issue a permit to construct if satisfied that the holding tank is adequate to deal with the
domestic sewage originating from the structure and that the use of the holding tank will not, if
the maintenance plan is followed, cause a health hazard. Conditions may be attached to the permit
as appropriate. When the Holding Tank Construction Permit is approved and signed by the
Environmental Health Officer, the applicant may proceed with the construction and installation. The
installation of the holding tank and related works shall follow good engineering practice and be
inspected and sealed by an Authorized Person.
4. WHEN CAN I START USING THE HOLDING TANK?
When the installation of a holding tank is complete, the applicant must submit a “Letter of
Certification” and supporting documentation to the local Health Protection Office. A holding tank
must not be used until the Letter of Certification has been accepted by the Health Authority.
B. HOLDING TANK SPECIFICATIONS
1. HOLDING TANK CAPACITY
A holding tank receives wastewater from toilets, baths, washbasins, showers, sinks, and washing
machines. Water from roofs, yards, or foundation drainage must not enter the holding tank and must
be diverted away from the location of the tank.
The capacity of the holding tank shall be at least seven times the estimated minimum daily sewage
flow, but not less than 4900 litres/1295 gallons (see Table 1 below).
Notes: Homeowners should review the hauling costs associated with local wastewater hauler truck
capacities to get the most efficiency out of the tank. Consider a larger tank that provides more
days of storage. In some circumstances, (i.e. remote areas) an Environmental Health Officer may
require a holding tank capacity greater than those listed in Table 1.
Reduction in water consumption will benefit the environment and reduce hauling costs by researching
ways to conserve water usage. For example, do not let water run unnecessarily and install low flow
shower heads and toilets.
TABLE 1. Minimum Holding Tank Capacities based on Estimated Daily Design Flow.
Capacities are listed in litres and US gallons
Number of Bedrooms
Estimated Daily Sewage Flow (litres/Gallons)
Holding Tank Capacity
1 700 l. (185 gal.) 4900 l. (1295 gal.)
2 1000 l. (264 gal.) 7000 l. (1850 gal.)
3 1300 l. (343 gal.) 9100 l. (2404 gal.)
4 1600 l. (423 gal.) 11 200 l. (2959 gal.)
5 1900 l. (502 gal.) 13 300 l. (3514 gal.)
6 2200 l. (581 gal.) 15 400 l. (4069 gal.)
Add 300 l/day for additional bedrooms
2. SETBACK DISTANCES (MINIMUM)
TABLE 2. Minimum Setback Distances From Holding Tank Location
Note: Install the tank in a location that provides easy access for pump-out, any time of the year.
Site the tank a minimum distance from the following:
15 m. (50 ft.) Surface Source of Drinking Water (includes lakes, rivers, etc.)
15 m (50 ft.) Domestic water supply well
1 m. (3 ft.) Property line
1 m. (3 ft.) Building or structure (where there is not a perimeter drain)
1 m. (3 ft.) Buried utility service
1 m. (3 ft.) Drinking water supply cistern, at or above ground
3 m. (10 ft.) Domestic water pipeline
Source: Sewerage System Standard Practice Manual Version 3 (September 2014)
3. CONSTRUCTION AND INSTALLATION
a. Tank Selection
Holding tanks can be constructed from a variety of materials and must be designed for its intended
usage. They can be prefabricated or they can be poured in place. Septic tanks are generally not
acceptable as holding tanks but dual purpose tanks may be available. Acceptable tanks can be
identified as having the current CAN/CSA B66 approval with designation as a holding tank; visible
by the “H” on the CSA approval stamp.
The type of tank that you choose may require additional information to be submitted with your
application. For example:
figure 1
• CAN/CSA approved prefabricated tank – A photograph of the CSA certification stamp on the tank
specifying the Holding Tank Designation “H” is required. Include the photo and a copy of the CSA
certification document specific to that tank with your application. See Appendix B – Tank Marking
(CAN/CSA Standard) for more information.
CAN/CSA B66
If proposing to use a prefabricated tank that is not the current standard (CAN/CSA-B66) then a
report from a Professional Engineer should accompany the design stating that the tank is equivalent
to CAN/CSA-B66 current standard and will not constitute a health hazard.
Tanks that are constructed on-site will require a Professional Engineer. This includes tanks that
are poured in place and may
See Appendix “B” for holding tank certification (marking) information
include those that come in pieces and are assembled on-site. Registered Onsite Wastewater
Professionals (ROWPs) cannot engineer a design in place. The application will require a tank
design and state that the tank is equivalent to CAN/CSA-B66 current standard and will not
constitute a health hazard.
Figure 1. Typical Holding Tank Sewage System and general information
b. Sizing
Proper sizing of a tank varies depending on intended usage. See TABLE 1. Minimum Holding Tank
Capacities based on Estimated Daily Design Flow
c. Location
Locate the tank to protect it from physical damage and so allow for easy access for the pumping
truck. In areas where a high water table exists, additional precautions may be required (i.e.
anchoring that would require a Professional Engineer).
d. Installation
The installation of the holding tank and related works shall be completed and inspected by an
Authorized Person. An accepted Letter of Certification is required by the Health Authority prior
to operation and is a condition of the construction permit. After installation, but prior to use,
the water tightness of the tank must be tested.
e. Access
Holding tanks must have access openings at or above finished grade and with the ground graded to
slope away to divert surface water. Access risers must be watertight at the connection to the
holding tank and at the joints between all sections. To prevent unauthorized or accidental entry
into a holding tank, openings must be equipped with a secure lid or cover. In extremely cold
climates, the access riser must be insulated to prevent freezing.
f. Tank Bedding and Backfill Information
Follow the manufacturer’s standards, including maximum depth for burial. Ensure any bedding layer
below the tank is compacted before installing. Holding tanks should be backfilled evenly on all
four sides in 30 cm lifts, with compaction, to final grade. Risers and lids are not to be shifted
or distorted when backfilling. Tanks and piping must be adequately protected from freezing.
g. Piping
The inlet piping (sewer pipe) connected to the holding tank must be protected from distortion
caused by settling of the backfill material. The excavation for a tank should not be any larger
than is necessary to install the tank. This provides undisturbed earth closer to the tank to
support the sewer line leading into the holding tank. Piping connected to the holding tank must be
supported to within 30 cm of the tank on a solid base. In addition, holding tanks buried in the
ground require the installation of a flexible coupling near the entrance to the holding tank and at
the point at which the pipe to the holding tank exits from the building.
4. ALARM
A functional audible and visual high level alarm will alert the owner/resident if the tank needs to
be pumped out. The sewage alarm level should be activated at 75% capacity and the audible alarm
setting at no greater than 90% of the tank capacity. The alarm shall be connected to the water
supply pump switch to automatically shut off the pump when the sewage level is a maximum of 90% of
the tank capacity. A qualified electrician must ensure a proper high water alarm system and
connection to a separate circuit from the pump. In situations where a
continuous source of electricity is not available, the holding tank must be equipped with some form
of visual indicator that alerts the owner/resident if the tank needs to be pumped.
5. MAINTENANCE PLAN
A written “Holding Tank Maintenance Plan” must be developed and forwarded to your local
Environmental Health Officer with the Holding Tank Permit Application. The maintenance plan should
include the following information:
Contact information for sewage hauler,
Availability of sewage hauler,
Distance to sewage hauler and estimated response time,
Contact information for approved waste disposal site,
Estimated frequency of pump out,
Scheduling for routine inspections of alarm system,
Emergency contact information (e.g. owner, electrician, plumber, sewage hauler’s “after
hours” contact number, Environmental Health Officer, etc.)
Any other items as requested by an Environmental Health Officer.
A copy of the “Holding Tank Maintenance Plan” should be kept on-site as a reference for the
homeowner/occupants.
The owner must keep operational and maintenance records, including information about pumping
frequency, sewage volume pumped, disposal site, proof of acceptance by treatment and disposal site,
and system servicing and repairs. A copy of the “Holding Tank Maintenance Plan” and other
important records must be maintained for reference. These records may be requested for
review by an Environmental Health Officer.
Under no circumstances is sewage from a holding tank to be discharged onto the surface of the
ground or into groundwater or surface waters.
6. RESOURCES
Go to Interiorhealth.ca; Your Environment; Healthy Built Environment; Sewerage to obtain:
• Holding Tank Permit Application Form
• Holding Tank Letter of Certification Form
APPENDIX A – EXAMPLE OF A SITE PLAN
APPENDIX B – TANK MARKING
CAN/CSA Standard (as of March 05, 2015)
Source: CSA Group Class Number 6921-01 Plumbing Fixtures – Septic and Sewage Holding Tanks for
Plumbing Systems
TANK MARKING:
Each tank shall be permanently marked, legible and readily visible and located on top of the tank
near the access opening or at the end of the tank near the inlet. In addition, the inlet and outlet
shall be marked to indicate the direction of flow. The marking or label shall include the
following:
• manufacturer’s name or trademark;
• the last two digits of the year of manufacture;
• the working capacity of the chambers (in litres);
• the volume of the chamber(s) per centimetre of depth, expressed in litres;
• the type of tank, i.e., sewage holding tank (H), trickle-type septic tank (T), septic tank
with siphon (S), septic tank with pump (P), effluent chamber with siphon (ES), or effluent chamber
with pump (EP);
• the maximum burial depth for which the tank is designed, expressed in metres;
• the liquid depth of the septic tank if less than 1200 mm, expressed in millimeters;
• for a concrete tank, a marking to indicate whether it is suitable for sulphate or non-
sulphate soils, i.e., “SUL” or “NON-SUL”;
• ” above ground installation not permitted ” or ” AGINP ” (where applicable); and
• the CSA monogram.
Tank marking shall also include a permanent warning advising against entry into the tank and the
word “DANGER”. The warning shall be in English and French and shall be located on the access
opening lid(s), applied at the factory.
