How is hard surface area calculated?

For billing purposes, stormwater charges will be based on the amount of hard surface on your property. Hard surfaces within the city’s right of way (roads, boulevards and sidewalks) are not included in your property’s hard surface area.

The hard surfaces of a property will be measured using high-resolution aerial photography. This will provide the basis for the quarterly bill. Due to the possibility for error using aerial photography, each property’s hard surface area was reduced by 100 square feet before calculating the stormwater utility charge.

Newly-developed properties will have their hard surface area determined using the approved site plan. Property owners will have the opportunity to appeal the measurement. In these cases, the property owner can provide their own measurement and submit it to the city for review.

Typical Lot showing impervious and pervious surfaces
Pervious examples
The example above shows a parcel with a house, garage, deck (with pavement below) and areas of brick, gravel and concrete pavement.

The diagram above shows impervious areas of the property above in gray and pervious areas in blue. 



The hard areas (shown in gray in the example above on the right) of a property will be calculated to the square foot and are billable.

The area in yellow (the sidewalk and street right-of way) are non-billable.





Show All Answers

1. Is Royal Oak the only city that has a stormwater utility?
2. Why is stormwater run-off a problem?
3. What are some examples of pervious & impervious surface areas
4. How is hard surface area calculated?