Home> Septic Tank Sizing Calculator

Alberta Septic Tank Size Estimator (SOP 2021)

This is an estimate only, and cannot be used for design purposes. Imperial gallons are primary. Table 4.2.2.2 minimums may be used when no additional-flow conditions exist; otherwise sizing uses the greater of Table 4.2.2.2 and Article 4.2.1.1 (Peak + sludge/scum).

Home details

Bedrooms

Expected occupants (SOP peak-flow rule)

—

≤2 bedrooms: 2 people/bedroom. ≥3 bedrooms: 1.5 people/bedroom.

Fixture Units (FU) builder

Full Bathrooms (bathroom group)

Bathroom group = 6 FU

Half Baths (toilet + basin)

Toilet (flush tank)=4 FU, Basin=1 FU

Bidets

Bidet = 1.5 FU

Laundry Standpipes

Laundry standpipe = 2 FU

Laundry Trays

Laundry tray = 1.5 FU

Kitchen Sinks

Kitchen sink = 2 FU

Total Plumbing Fixture Units (FU)

—

Calculated from the selections above (dishwashers excluded).

FU threshold for this bedroom count

—

If FU exceeds threshold, additional-flow rules apply.

Additional flow conditions

Garbage Grinder (Garburator) Water Softener Discharge (adds 15% to peak)

Soaker / Hydro Tub Count

Tub Volume (Imp. gal) (each)

Adder: (Tub Vol − 75) × 2 (per tub), minimum 0.

High Flow Shower (L/min)

If >13 L/min, adds 11 Imp. gal/day for each extra 6 L/min (or part).

Other High Capacity Fixture (Imp. gal/day)

Water Treatment Discharge (Imp. gal/day)

Get Soilworx Design Help

Estimator only. Final design requires site evaluation + SOP compliance review.

Results

Estimated Peak Daily Flow (Design)

—

Article 4.2.1.1 Sludge/Scum Storage Allowance

—

Article 4.2.1.1 Working Capacity (Peak + Sludge)

—

Table 4.2.2.2 Minimum Working Capacity

—

Minimum Septic Tank Working Capacity (Applied)

—

Calculation breakdown

403-899-8992

Alberta Septic Tank Size Estimator (SOP 2021)

Home details

Fixture Units (FU) builder

Additional flow conditions

Results