What is stormwater and what is impervious area?
When water from rain and snowmelt washes off a piece of property, it flows into a storm drain system and eventually into the Huron River. The impervious or hard surfaces on the property—such as roofs, driveways, and patios—do not absorb the water and contribute to water runoff. Federal and state regulations require the City of Ann Arbor to address the amount of runoff and the pollution carried by the water that is deposited, untreated, into the Huron River. The initial half-inch of stormwater tends to carry the most pollution as it washes fertilizers, automotive fluids, animal waste, deicers, and dirt into the street and down the gutter. Greater impervious area = more stormwater runoff = degraded Huron River watershed.
How is stormwater usage measured by impervious area?
A computer analysis of infrared aerial photographs is able to distinguish hard, impervious surfaces in contrast to areas that can absorb stormwater, such as lawns and gardens. The computer program assigns the residential property into one of four billing tiers to more equitably distribute costs proportional to use instead of using a flat fee. Homes with larger impervious areas pay more. You can review your property's stormwater assessment online and, if desired, submit an appeal (see below).
How will the new stormwater rate system work?
Stormwater Brochure (pdf) - 4-page overview of the stormwater rate structure (2007 data)
Stormwater Rates - For residential and commercial customers
Stormwater credits - actions you can take that will reduce quarterly stormwater charges
Online Impervious Area Analysis and Appeal Process: A computer analysis of infrared aerial photographs was used to distinguish hard, impervious surfaces in contrast to areas that an absorb stormwater, such as lawns and gardens. The computer program assigns each residential property into one of four billing tiers to more equitably distribute costs proportional to use instead of using a flat fee. You may review your aerial photograph online and if you do not think the tier assigned your property is accurate, you may submit an appeal by mail. The online review and appeal process is describe in the above link.
Announcements, as available, will be posted here for scheduled rain barrel or rain garden workshops, bulk rain barrel sale events, etc. Please follow link to events.
Updated July 1, 2008