Charges are calculated using property size (A), development intensity (I), and a runoff coefficient (R), based on land zoning and a city-wide monthly rate.
A x I x R x Rate = Stormwater utility charge
- A: The area of the property in square metres (m2), and the proportion of the building lot area attributable to each unit for multiple units sharing a single building of property.
- I: The measure of the portion of lot being used for its intended development. The development intensity factor is typically 1.0, except for properties where owners demonstrate the contribute significantly less stormwater runoff per property area to the City's land drainage system during rainfalls than other similarly-zone properties.
- R: Run-off coefficient—the permeability of your lot's surface (i.e. grass versus concrete), based on land zoning.
Rate: The monthly charge of $0.042506 per square metre (m2).
- The run-off coefficient for a single detached residential house is typically 0.50. However, depending on your property's land zoning classification, the run-off coefficient can range from 0.20 to 0.95.