Systems Planning

Residential Storm Water Credits

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​​Single and two-family residential properties are placed in one of four rate tiers, depending on the square footage of impervious area. 

Residential credit options

You can take steps to reduce your stormwater bill.  You can partner with us to reduce stormwater runoff at the source. This is the best way to create a healthy Huron River watershed. ​

If you are a one- or two- family residential customer, consider using up to three of these optional stormwater credits. Please call 734.794.6320 or email with the description of your credit and your address. 

  • Make your home a RiverSafe Home partner (save $1.03/quarter). Visit the RiverSafe home​ and take the survey. The survey is also available by mail, just call 734.222.6833. There is no cost to enroll. Once completed, please email with your address to obtain credit. 

  • Install Rain Barrels on your downspo​uts (save $2.71/quarter, total, for one-to-five rain barrels).  35 gallons is the minimum size rain barrel for the credit. ​Rain barrels are sold locally at many garden centers and online. Rain barrel image for stormwater campaign.png

  • Create a Rain Garden, Cistern, or Drywell (limited to one of these options per property to save $5.62/quarter). In addition to being beneficial for the watershed, rain gardens can be a very attractive landscaping feature.  For details on how to qualify for these options, download the following PDF information sheets for constructing a: Rain GardenCistern, or Drywell. ​

  • To request a credit or for additional information, please contact Note: If you are requesting a rain garden / rain barrel credit please indicate the size of the feature, and percentage of your roof that is captured by the feature.
  • If you have nonresidential property or residential apartment units larger than two units, you may qualify for commercial credits.


Planning and Development Services- Storm water management plan is required for residential construction projects with 200+ sq. ft. of impervious surfaces Visit the Residential Storm Water Code Requirements page for more information about the code changes and to download an impervious​ area worksheet that will help you determine if your project will require storm water management as part of the grading permit application process.

Office of the Washtenaw County Water Resources Commissioner - This site has annotated case studies of dozens of local rain gardens created in Ann Arbor, including the landscape design, plant materials, and four-season photographs.

Huron River Watershed Council - Local nonprofit organization specializing in local water protection and coordinating periodic bulk rain barrel sales. 734.769.5123​

Rain gardens​

City of Ann Arbor - design guide (PDF) for storm water​ credit . 

Wisconsin Department of Natural Resources - Information on rain gardens.

Rain barrels

Washtenaw County Conservation District sells rain barrels.  They have sold them since 2011 and offer black, grey or terra-cotta colors, 55 gal. in size.  They are made from food-grade plastic barrels that have been cleaned and repurposed as rain barrels and are made in the U.S.A. 

Rain Barrel Guide - Source of commercially-available rain barrels for comparisons 

King County Natural Resources and Parks - Information on rain barrels

Permeable p​avement

Michigan Conc​re​te Association - Information on permeable concrete  ​

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