Permeable resin-bound surfacing can be proposed as a volume control measure in Chicago as the wearing course of a permeable paving section built to the Department of Water Management's criteria, with a civil engineer certifying the subsoil. The Regulations don't name resin-bound, so the Department of Buildings stormwater reviewer decides whether the surface is accepted. Under the City's 2026 Regulations for Sewer Construction and Stormwater Management, a Regulated Development must capture one-half inch of runoff from all impervious surfaces, or, if it doesn't discharge directly to waters or a separate storm sewer, cut impervious area 15 percent from existing conditions.

On a tight city lot with no room for a basin, a permeable parking court or plaza can carry part of that load. The limit is just as local: Chicago's stormwater manual counts permeable pavement as a permeable surface only when its stone has no underdrain and isn't used for detention.

What triggers Chicago's stormwater ordinance, and where permeable paving sits in it

A project becomes a Regulated Development when it disturbs 15,000 square feet or more, creates 7,500 or more substantially contiguous square feet of at-grade impervious surface, or discharges to waters or a separate sewer. Regulated Developments must also provide rate control for the 100-year storm, with narrow exceptions for some sites that discharge directly to waters such as Lake Michigan. Detached single-family and two-family residential development, in-kind maintenance and projects entirely within the public way fall outside the plan requirement.

Permeable paving appears in the Regulations as a volume control BMP with its own design criteria. Most of the city drains to combined sewers that feed the Metropolitan Water Reclamation District's interceptors, so every gallon held back on site matters downstream. What doesn't count is a resin-bound finish bonded to an existing slab: rain passes through the top layer, then runs off the concrete underneath. That is a resurfacing job (see our Chicago concrete resurfacing page), not a stormwater measure.

Lake-plain clay, sand pockets and groundwater: notes for the base design

The City's manual maps the sandier ground near the lake against the heavier clays found across much of Chicago, and the Regulations translate that into hard rules the engineer will design around:

Subsoils need at least 0.5 inches per hour of infiltration; below that, an underdrain is required, with the top 3 inches of impermeable soil mixed with sand.
The bottom of the aggregate sits at least 2 feet above groundwater or bedrock, and an outlet pipe to a combined sewer at least 3.5 feet above the water table.
Uniform sand to 2 feet below the BMP allows an assumed 1.4 inches per hour; anything else needs percolation tests.
Slopes stay between 0.5 and 5 percent, the stone base drains within 48 hours, and run-on from conventional pavement is capped at 3:1.

Freeze-thaw cycling and road salt add a Chicago-specific layer: open-graded, fines-free stone and a winter plan that bans sanding are part of keeping the section working.

Where a permeable resin-bound section earns its place in Chicago

Commercial parking lot rebuilds on neighborhood corridors, where 7,500 square feet of reconstructed pavement brings the ordinance into play and land is too valuable for a basin.
Mid-rise residential courtyards and entry plazas on lot-line infill sites, where the open space is small but still needs volume control.
Schoolyards and campus walks, where a smooth, accessible surface has to sit next to play areas and drain quickly after storms.
Two-flat and bungalow patios outside the ordinance, where owners simply want less roof and patio water heading into the combined sewer.

Alleys, sidewalks and parkways are public way, controlled by the City rather than this ordinance. Keep resin-bound on private property unless the City approves otherwise.

Getting a permeable section through DOB stormwater review

The Department of Water Management has designated the Department of Buildings as its agent, so the Stormwater Management Plan goes through DOB, and its stormwater reviewer issues the checklist for final approval. Expect to submit soil borings, the engineer's subsoil letter, volume control calculations from the City's spreadsheet tool, and an operations and maintenance plan.

Resin Rock supplies the system: UV-stable binder, natural stone blends, trims and Rock Crete, a permeable resin-bound base layer the engineer can evaluate as part of the section. Your designer can pull our technical data sheets for the specification, and we can match you with an approved installer trained on our hands-on program, usually within 24 hours.

Before you specify permeable resin-bound in Chicago

Confirm whether the site is a Regulated Development under the 15,000 and 7,500 square-foot tests
Order soil borings and, unless uniform sand is found, percolation tests for the permeable area
Check seasonal high groundwater against the 2-foot and 3.5-foot separation rules
Hold slopes between 0.5 and 5 percent and run-on at no more than 3:1
Add a check valve where an underdrain invert sits within 1 foot of the combined sewer crown
Write the O&M plan, including winter maintenance with no sanding

Common questions about permeable resin-bound in Chicago

Does a resin-bound patio at my two-flat need a city stormwater plan?

Usually not. Plans are triggered by 15,000 square feet of disturbance, 7,500 square feet of at-grade impervious surface, or discharge to waters, and detached single and two-family residential development is excluded. Other permits can still apply, so check with the Department of Buildings. Built on a permeable base over suitable soil, the patio still sends less water to the combined sewer.

Can resin-bound laid over our existing parking lot count toward volume control?

No. Over solid asphalt or concrete the water drains through the finish and then runs off the slab, so it provides no volume control. To count, the old pavement comes out and a permeable section goes in: open-graded stone, an engineer-certified subgrade and, on low-infiltration soils, an underdrain designed to the Department of Water Management criteria. The DOB reviewer decides whether the resin-bound surface is accepted.

Our site is on heavy clay. Is permeable paving still worth it?

It can be, with an underdrain. The Regulations require one when subsoils infiltrate less than 0.5 inches per hour. The manual then treats that area as impervious in volume control and detention calculations, so the engineer counts the storage in the stone rather than infiltration. Whether that beats a vault or green roof depends on your site.

Official sources for Chicago

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.

Permeable Resin-Bound Surfacing in Chicago, IL