Private sewage in Alberta is governed by the Safety Codes Act, the Private Sewage Disposal Systems Regulation and the Alberta Private Sewage Systems Standard of Practice. The 2021 edition — the fourth — is the one in force, and it has applied to permit applications since November 1, 2022.
- Standard in force
- 2021 SOP
- In force since
- Nov 1, 2022
- Tank to well
- 10 m min.
- Open discharge to line
- 90 m min.
The systems you will find
The Standard recognizes a family of system types. On Calgary-area acreages you will most often meet:
- Septic tank and treatment field — the tank settles solids and effluent is distributed through laterals (weeping tile or chambers) in the soil.
- Treatment mound — a raised, engineered bed used where native soil or groundwater conditions won't treat effluent in a conventional field.
- Open discharge — effluent pumped to the ground surface, common on older, larger parcels and now heavily restricted.
- Packaged treatment plants, drip dispersal and at-grade systems — more specialized designs with their own maintenance needs.
In November 2025 the province confirmed that certified combined treatment-and-disposal systems are accepted under the 2021 Standard, within limits — pressure distribution only and a peak flow no greater than 5.7 m³ per day.
Sizing and siting the tank
The Standard sets a minimum working capacity for a house's septic tank by bedroom count:
| Bedrooms | Minimum working capacity |
|---|---|
| 1 to 3 | 3,360 L (740 imp. gal.) |
| 4 | 4,260 L (940 imp. gal.) |
| 5 | 5,220 L (1,150 imp. gal.) |
| 6 | 6,130 L (1,350 imp. gal.) |
A tank must sit at least 10 m from a water well or water course and at least 1 m from a property line and from a building. When a basement is developed into extra bedrooms, the question becomes whether the original tank still meets the Standard for the home as it is used today.
Treatment field and mound setbacks
| Minimum distance to | Treatment field | Treatment mound* |
|---|---|---|
| Water well or water source | 15 m | 15 m |
| Water course | 15 m | 15 m |
| Licensed municipal water well | 100 m | 100 m |
| Property line | 1.5 m | 3 m |
| Basement, cellar or crawl space | 10 m | 10 m |
| Septic tank | 5 m | 3 m |
*Mound distances are measured from the toe of the berm.
These distances protect the well you drink from and the foundation you live over. They also limit where a future shop, garage or addition can go — a useful thing to know before you buy with plans.
Open discharge: legacy systems and new limits
Open discharge systems carry the strictest distances in the Standard. The point of discharge must be at least 90 m from a property line, 45 m from any building, 50 m from a water well or source, 45 m from a water course and 100 m from a licensed municipal well. Effluent must stay on the property and must not travel more than 30 m before soaking in.
Density matters too: a new open discharge system cannot be installed on a property in a quarter section where more than four parcels have already been subdivided out. Existing systems may keep operating, but if one fails on a smaller parcel in a subdivided quarter, replacement will likely mean a different technology — and a different budget.
Permits and the paper trail
The Safety Codes Act requires a permit before work begins on a private sewage system, and installers must hold a current certificate of competency to obtain one. For a property you are buying or selling, the useful documents are the permit, the inspection record and any as-built drawing showing where the tank and field actually are. Permits are generally issued through the municipality or its accredited agency; ask the county which applies.
What a good inspection covers
A general home inspection rarely goes underground. A septic-specific inspection by a certified professional typically pumps and examines the tank (baffles, lids, cracks and the sludge and scum layers), checks the pump and alarm on pressurized systems, and looks for signs of saturation or surfacing over the field. On a purchase, ask for the pump-out record as well — frequency and findings say a lot about how the system has been used.
Your checklist
- Permit and inspection record for the system as installed
- As-built drawing or a located tank and field
- Tank size compared with the current number of bedrooms
- Recent pump-out receipt and a septic inspection by a certified professional
- Setbacks from the well, buildings and property lines confirmed
- For open discharge: parcel density in the quarter section and distance to the property line
How Dusko uses this
Wastewater is where many acreage deals wobble. Dusko asks sellers for the permit trail and a recent pump-out before listing, and writes a septic inspection condition for buyers with time to act on what it finds.