In Evanston, a permeable resin-bound surface can be part of stormwater management when it tops an infiltrating permeable pavement section and MWRD accepts that section. The Metropolitan Water Reclamation District's Watershed Management Ordinance lists porous pavement as a retention-based practice and does not count infiltration-designed permeable pavement as impervious area, but it does not name resin-bound, so acceptance is the reviewer's decision. Laid over an old slab, it is only a new finish.
Evanston sits outside Chicago but inside MWRD's suburban Cook County jurisdiction, so larger sites answer to the WMO while City Engineering reviews grading and stormwater on building permits. Most of the city drains to combined or relief sewers that empty into MWRD's system, which is why keeping water on site has real value here.
MWRD's first inch, and the City's own detention rules
The WMO, as amended January 9, 2025, applies volume control to non-residential and multi-family development on property holdings of half an acre or more and to residential subdivisions of an acre or more. The volume control storage is the first inch of runoff from the impervious area, and practices to capture it are required once impervious area reaches 0.10 acre. Retention-based practices that infiltrate come first, and those discharging to a combined sewer need a backflow prevention device.
Below the WMO thresholds, Evanston applies its own detention rules. The City's 2023 Stormwater Master Plan notes that smaller buildings and one to three homes on small lots are generally exempt, that parking lot resurfacing is currently exempt, and that a fee-in-lieu option exists. It also recommends tightening several of those exemptions, so confirm the current rules before you design.
Lakefront sand, inland clay and a sewer system that backs up
Evanston's ground changes quickly between the lakefront and the North Shore Channel. The Master Plan points to sandy soils, such as those around Mason Park, as the best places to infiltrate, while heavier soils inland will need an underdrain. The City's stormwater guide, which follows MWRD's Technical Guidance Manual, sets the screening numbers for volume control practices: infiltration rates between 0.5 and 2.41 inches per hour, and the bottom of the storage at least 3.5 feet above seasonally high groundwater.
Soil contamination can rule infiltration out, and so can maintenance exposure: the guide flags sites next to beaches or sandy ball fields where windblown sand can clog voids. Freeze-thaw and plowing season mean the engineer should size the open-graded base for frost and specify an edge detail that survives snow equipment.
Projects that suit Evanston's mix of campus, courtyard and bungalow
- Campus walks and plazas near the lakefront, where sandy soils can take water and foot traffic is heavy.
- Vintage courtyard apartment buildings replacing cracked courtyard paving, often in combined-sewer blocks prone to basement backups.
- Downtown mixed-use redevelopment that crosses the half-acre WMO line and needs first-inch storage on a small footprint.
- Church, school and clinic parking being rebuilt rather than resurfaced, which turns a maintenance job into a stormwater opportunity.
Permits, upkeep promises and how Resin Rock fits in
For sites at or above half an acre, the Watershed Management Permit comes from MWRD, because Evanston is not one of the District's authorized municipalities. Ask City Engineering at pre-application what the City needs alongside it.
Plan for long-term upkeep too. An MWRD permit application includes a perpetual maintenance program for volume control practices, and the City's plan for its own Civic Center permeable parking lot is a good model: owner inspections and sweeping three times a year, and no seal-coating, stockpiling or sand for traction.
Resin Rock supplies binder, stone blends, trims and Rock Crete permeable sub-base for the engineer to evaluate. We match owners with approved installers and run hands-on installer training in Illinois for local crews.
Before you specify permeable resin-bound in Evanston
- Measure the property holding and impervious area against the WMO half-acre and 0.10-acre tests
- Find out whether the parcel drains to combined, relief or separate storm sewer
- Test infiltration and confirm 3.5 feet to seasonally high groundwater
- Screen the site for soil contamination before planning infiltration
- Budget for regular inspections and vacuum sweeping; the City's Civic Center lot plan uses three a year
- Specify winter care without sand or seal-coating
Common questions about permeable resin-bound in Evanston
Will a resin-bound driveway at my Evanston house need MWRD review?
Not usually. WMO volume control starts at half-acre multi-family and non-residential sites and one-acre residential subdivisions, and the City exempts most small residential lots from detention. Your driveway still needs City permits. If it sits on a permeable stone base over workable soil, it will also send less water into a combined or relief sewer that already struggles in big storms.
Does MWRD count permeable pavement as impervious area?
Not when it is designed to promote infiltration. The amended WMO excludes porous or permeable pavement built for infiltration from its definition of impervious area and lists porous pavement as a retention-based practice. Whether a resin-bound section counts as porous pavement is MWRD's call. A resin-bound finish glued to existing concrete is different: the slab underneath is still impervious, so neither MWRD nor the City should credit it.
Is there an Evanston fee credit for permeable paving?
We have not found a City stormwater fee credit that a permeable surface would reduce. The incentive that does exist is in the City's green building ordinance, which the 2023 Master Plan says gives credit for stormwater best management practices on covered projects. Ask the City whether a permeable resin-bound section, built on an infiltrating base, would qualify on yours.
Can we use resin-bound on a lakefront site with sandy soil?
Sandy ground is often the best place to infiltrate in Evanston, and the City's 2023 plan suggests adding green infrastructure to public projects in sandy-soil areas, such as around Mason Park. The trade-off near the lake is windblown sand, which the City's guide flags as a clogging risk near beaches and ball fields. Plan for more frequent vacuum sweeping and keep landscape edges from washing onto the surface.
Official sources for Evanston
- MWRD Watershed Management Ordinance and Technical Guidance Manual
- Evanston Stormwater Management Guide, December 2019 (PDF)
- Evanston Stormwater Master Plan, 2023 (PDF)
Local rules change. We last checked these sources in October 2026. Confirm current requirements with the reviewing agency before you design, and treat this page as a starting point, not engineering or permitting advice.