ompacted, and does not allow for infiltration. Water will always find the path of least resistance, and will tend to run downhill over compacted gravel rather than infiltrate into the underlying soils.
While stormwater may be contained within pools during a rain storm, the pool itself does not allow water from other parts of the property to soak into the soil. When the pool is drained, the stormwater that was collected will be sent to the sewer system. Considering pools as impervious surfaces is consistent with many other stormwater utilities throughout the country.
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 of 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.
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.
A stormwater utility covers the critical service of carrying stormwater runoff away from properties, conveying it within the city’s combined sewer system to treatment facilities and ultimately discharging it to the Detroit River. Properly operated stormwater infrastructure prevents flooding and backups, expensive repairs, and pollution of natural waterways. While the city currently operates a combined sewer system, the method of funding this operation and the associated costs for treatment has been determined to be outdated by current standards. The city’s proposed stormwater utility will proportionally bill users for their use of the system and will encourage activities that promote better stormwater management and lessen the burdens of the system, making the existing infrastructure more adaptable to severe rain events.
The city used low-altitude, high-resolution aerial photography to determine the hard surface area on each property. The city will perform aerial flyovers every three years to update the hard surface database.
Using aerial photography is the best possible way to measure each property’s individual hard surface area. However, mapping of aerial photographs does have a degree of inherent error. The hard surface area on each property was therefore reduced by 100 square feet to account for error in the measurements.
The image below is an example of aerial photography. The area outlined in blue represents the hard surface area. The pop-up block indicates the Billable Hard Surface Area of this property is 91,215 sq. ft.
To view your property go to: https://royaloak.maps.arcgis.com/apps/webappviewer/index.html?id=88ea895ad7f34bdb885f3994d431f972
Royal Oak has a "combined" sewer system, which means that all the stormwater from rain and snow is mixed with all the sanitary sewage from private sewer leads into one pipe. Parts of the city do have separate stormwater pipes and sanitary sewer pipes, but these all ultimately drain to the same county drain and are combined. This means that the city has to pay to treat all the sewage AND stormwater that enters the system.
Roads and public rights-of-way maintained by the city are exempt from the stormwater utility fee because they function as part of the stormwater collection and conveyance system. City-owned properties such as parks and parking lots are subject to the stormwater utility fee.
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