StormStore is powered by nearly a decade of research on the benefits of stormwater credit trading for developers, engineers, and landowners.


Metropolitan Planning Council and The Nature Conservancy conducted research on the viability of stormwater credit trading in Cook County and the benefits credit trading would offer for developers, landowners, and local communities.

StormStore Feasibility Study – Cook County (2017)

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StormStore Feasibility Study – Chicago (2019)

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2019 StormStore Market Admin Analysis Exec Summary

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2019 StormStore Market Admin Analysis Full Report

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Frequently Asked Questions

What is a stormwater credit?

A stormwater credit is a term that refers to a volume of stormwater that has been voluntarily constructed and verified by the Metropolitan Water Reclamation District (MWRD) to meet the high-quality standards of the Watershed Management Ordinance (WMO). Credits are measured in Acre-Feet (ac-ft)), which is a unit of volume that represents the amount of water required to cover an acre of land to a depth of one foot.

Developers with an eligible project can use stormwater credits to meet a portion of management required by the WMO. This can help reduce the amount of on-site stormwater management required, which can reduce construction costs and increase usable space on the site.

What types of stormwater management practices qualify for stormwater credits?

Stormwater management practices that qualify for stormwater credits include green infrastructure practices such as rain gardens, bioswales, and green roofs, as well as other stormwater management practices such as detention basins and infiltration systems.

What is the cost and value of a stormwater credit, and how much is a credit worth?

The cost of each credit will need to be negotiated on a trade-by-trade basis between the buyer and seller. Generally speaking, the seller will set the sale price based on the total pre-planning, planning, design, construction, and long-term maintenance costs for the facility they build. While the cost of a credit can vary depending on factors such as location, market demand, and the type of stormwater management system being used, the price will often result in cheaper, easier, and greener stormwater management for buyers.

Despite the cost, buying stormwater credits can be a smart investment for developers. Our team can help you with all aspects of buying and selling stormwater credits, including helping sellers set a fair price, supporting buyers in finding and securing credits, or supporting buyers and sellers in finalizing credit trade agreements. If you're interested in buying or selling stormwater credits, please contact us today to learn more about how we can help.

Is there a limit to the number of credits I can buy for my project?

Yes, there is a limit to the number of credits that can be used to meet permit requirements for a development project. The Metropolitan Water Reclamation District (MWRD) allows developers to use stormwater credits for:

  1. up to 50% of their volume control (retention) storage needs, and
  2. the difference between the 10-year and 100-year detention volume needs.

To determine how many credits your project is eligible to purchase, contact the StormStore team for assistance, or refer to the MWRD's Watershed Management Ordinance (WMO) for guidance on calculating your project's stormwater management requirements.

Does it cost anything to work with StormStore, and how can StormStore help with stormwater credit trading in Cook County?

No, there is no cost to working with StormStore. Our team provides pro bono support to anyone who would like to learn more about stormwater credit trading in Cook County. We are committed to promoting sustainable stormwater management practices, and providing pro bono support helps to make these practices more accessible to a wider range of stakeholders.

Working with StormStore offers a range of benefits, including the opportunity to learn more about stormwater credit trading, evaluate your site's potential for stormwater management, and access pro bono support from a knowledgeable and experienced team. Whether you have a project in the pipeline and are looking for credits to buy, or you just want to talk about the benefits of stormwater trading, we can help you!

Who is eligible to participate in the stormwater credit trading program, and what are the requirements for eligibility?

Developers, engineers, and public & private landowners within the Little Calumet River or Lower Des Plaines River Watershed Planning areas are generally eligible to participate in the stormwater credit trading program. However, eligibility requirements may vary depending on the specific project and location.

Developers and Engineers:

Projects in the Little Calumet or Lower Des Plaines Watershed Planning Areas that trigger the MWRD’s Watershed Management Ordinance (WMO) are eligible to purchase credits to meet their stormwater management requirements without first demonstrating existing site constraints or limitations. Verify your project's eligibility using an address.

Public and Private Landowners:

Many 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. Verify your project's eligibility using an address.

Credit Generators and Sellers:

Stormwater credits—also known as offsite facilities—must be voluntary storage, and not storage otherwise required by the Watershed Management Ordinance. Credits cannot collect stormwater runoff that is already managed by a different facility. Verify your project's eligibility using an address.

Note: Projects in the four additional Cook County Watershed Planning Areas (Polar Creek, Upper Salt Creek, North Branch of the Chicago River, and Calumet-Sag Channel) may also be eligible to participate in the stormwater credit trading program if they demonstrate site constraints or limitations to meeting Watershed Management Ordinance requirements. If you're unsure whether your project is eligible, contact us today for a free consultation.

Are there any restrictions for projects within an eligible area?

Yes. Projects that are located within an eligible area for stormwater credit trading may be subject to restrictions that limit their suitability for credit generation. For example, projects that are partially or fully located within a Flood Protection Area (such as a Floodway, Floodplain, Wetlands, or Riparian Environments) may not be good candidates for credit generation.

To determine whether your project is eligible for stormwater credit trading, you can contact the StormStore team for a free consultation. You can also visit the Watershed Management Ordinance (WMO) website for up-to-date contact information to set up a pre-application meeting with the Metropolitan Water Reclamation District (MWRD). Our team can help you navigate any restrictions or requirements that apply to your project and provide guidance on how to proceed.

Can I generate stormwater credits on my property, and if so, what factors determine its suitability for credit generation?

If you have access to stormwater detention or green stormwater infrastructure (GSI), your property may be a good candidate to generate stormwater credits. Stormwater credits can be generated by any new, voluntary stormwater facility, including green infrastructure. However, the cost-effectiveness of credit-generating projects can vary.

If you are planning a construction project, considering improving your landscaping, or have space available to help reduce flooding in your community, the StormStore team can help you determine whether your property is a good candidate for generating stormwater credits. Contact us today for a free consultation to see how StormStore can help make your property work for you.

Who can I trade with?

In order to trade stormwater credits, you can only do so with parties who are developing projects within the same watershed as your project. This means that if your project is located in the Little Calumet Watershed Planning Area, you can only sell or trade credits to potential buyers who are developing projects in the same watershed.

Furthermore, it's important to note that buyers and sellers must follow the credit trade agreement and abide by the requirements set by the Metropolitan Water Reclamation District (MWRD) for stormwater management. This ensures that the credit trading process is fair, transparent, and in compliance with regulations. If you have questions about trading credits or need help finding potential buyers or sellers, don't hesitate to contact the StormStore team for assistance.

When should I consider stormwater credit trading, and what types of projects are well-suited for generating stormwater credits?

If you are a developer in the scoping and planning stages of a new development or redevelopment project that is likely to trigger MWRD's WMO, it's a good time to consider stormwater credit trading. This allows you to evaluate the cost-benefit of offsite compliance and potentially save on stormwater management costs.

Projects that have site limitations, such as poorly infiltrated soils, suspected contamination, significant underground utilities, or the need for underground detention facilities, are particularly good candidates for generating stormwater credits.

Property owners who are already planning construction or landscaping improvements on their property may also want to consider generating stormwater credits by installing credit-generating stormwater facilities at the same time. This is especially beneficial for sites that do not trigger MWRD's stormwater management regulations, as any stormwater runoff retained or detained by the new project may be eligible to generate credits.

In short, considering stormwater credit trading early in the planning process can help you optimize your stormwater management approach, potentially save on costs, and generate credits that can benefit your community. Contact the StormStore team for more information and to get started.

Check your eligibility:

Learn more about available credits in each watershed on our Credit Registry.

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