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Buyers: In the Little Calumet or Lower Des Plaines Watershed Planning Areas any developer who triggers the MWRD’s watershed management ordinance (WMO) is eligible to purchase credits to meet their compliance obligations. Per the WMO, most developments over 0.5 acres are required to provide stormwater management onsite, but starting in May 2020 MWRD is allowing developers to meet a portion of their stormwater management requirement using off-site facilities. StormStore can help developers find and match with available offsite facilities so that you can more cost-effectively meet your management obligations. Sellers: Any non-single family home landowner located in the Little Calumet or Lower Des Plaines Watershed Planning Areas can build an off-site facility and generate credits on their site, regardless of the size and type of project. A few things to consider for those landowners who are interested in generating credits: Any credit generating stormwater detention or retention projects must be new and voluntary. Both detention controls, such as wet/dry stormwater ponds, and retention volume controls, like rain gardens, permeable pavers, or other types of green infrastructure are eligible to trade through StormStore. Developers and landowners can also generate credits by installing new stormwater controls in excess of what is required under MWRD’s WMO, as long as it is shown that the excess storage is used to capture runoff from impervious surfaces that are not already managed by other stormwater controls. Any credit generating project must have an approved watershed management permit and pass MWRD’s construction inspection, regardless or size or type of project (even those type of projects that are considered exempt under the WMO) Landowners who generate credits for StormStore must also provide a maintenance contract and sign a sale agreement with the credit buyer and agree to provide long-term maintenance of new stormwater facilities.

There are no conditions that limit who can build, buy or sell projects as long as eligibility criteria are met or restrictions on where projects can be built and traded in the pilot Lower Des Plaines and Little Calumet watershed planning areas. The only requirement is that credits can only be traded within the same watershed. This means that if you build a rain garden in the footprint in the Little Calumet Watershed Planning Area you can only sell or trade credits to potential buyers who are developing projects in the Little Calumet watershed area.

Each stormwater credit represents 1 acre-ft of stormwater retention or detention storage. You can buy and sell more or less than 1 acre-ft per trade depending on your project needs. Buyers: Currently MWRD’s WMO caps the number of credits that can be purchased or traded by developers in order to minimize the rise of damage to local community and regional water resources and adjacent properties. Today developers can meet their stormwater management requirements by trading or purchasing up to 50% of their volume control or retention storage needs and the difference between the 10-year and 100-year detention volume needs. Reach out to the StormStore team to help you figure out how many credits you are eligible to buy or check out MWRD's WMO for more details on how to calculate your project’s stormwater management requirements. Sellers: For landowners looking to build new credit generating stormwater projects on their site, the only restriction in the number of credits that you can create is based on how much stormwater the project can receive from impervious surfaces, like rooftops, parking lots and roads, that are not already managed by other stormwater controls. The StormStore team may be able to help you figure out how many credits you are eligible to sell but you can also contact an engineer in your area to calculate your site’s credit generating potential.

StormStore is a partnership of The Nature Conservancy and the Metropolitan Planning Council formed to start-up a stormwater credit trading marketplace in Cook County, IL. The partnership supports the Stormwater Volume Trading Pilot operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRD). MWRD maintains all responsibility for permitting regulated development projects under the Watershed Management Ordinance (WMO).