Permeable resin-bound surfacing can count as a stormwater practice in Boston only when it sits on a permeable base such as Rock Crete over an open-graded stone reservoir that infiltrates, sized to the Boston Water and Sewer Commission (BWSC) retention volume, and BWSC accepts the design. Laid over an existing slab, it is a finish, not a recharge system, and it should not be presented to BWSC as one.

Boston adds two pressures most cities do not have. Since April 1, 2024, BWSC has billed a separate stormwater charge based on impervious area, with credits for qualifying practices. And in filled-land neighborhoods where buildings stand on timber piles, the Groundwater Conservation Overlay District requires recharge, not just detention. The sections below cover how a resin-bound pavement fits those rules.

BWSC retention volumes, the stormwater charge and where porous surfaces fit

In BWSC site plan review, projects under 100,000 square feet of floor area must infiltrate 1 inch of rainfall times the total impervious area on site, and larger projects 1.25 inches. BWSC accepts a 30% void ratio for storage within a stone area, which is the number that sizes the open-graded reservoir under any permeable surface.

The stormwater charge is based on impervious area. BWSC's credit program offers a 30% Best Management Practice credit for systems described in the Massachusetts Stormwater Handbook that meet its retention standard. Porous asphalt is on the eligible list, and BWSC says it will consider other BMP types that meet the Handbook criteria. Credits last five years and require a maintenance log and consent to random inspections, so whether a resin-bound section qualifies is decided by BWSC, not by the product.

Behind the city rules sit MassDEP's Stormwater Management Standards. The Handbook posted by MassDEP is the February 2008 revision, and an update is in progress, so confirm which version your filing will be reviewed under.

Made land, timber piles, marine clay and tides: what the base has to handle

Much of central Boston is filled land. Inside the Groundwater Conservation Overlay District, BWSC requires an infiltration system that captures at least 1 inch of rainfall, and green infrastructure there may not use an underdrain or be designed for capture and reuse, because the goal is to keep groundwater up around wood piles. That rules out the lined, underdrained section an engineer might otherwise choose on a tight lot.

Outside the overlay the constraints often run the other way. Marine clay, high groundwater and contaminated urban fill can make infiltration infeasible, in which case a permeable surface over an underdrain or liner is detention and treatment, not recharge. Along the harbor, Article 25A maps areas expected to flood in a 1% storm in 2070 with 40 inches of sea level rise, and a reservoir sitting in tidal groundwater will not drain. With hard freeze-thaw cycles and heavy de-icing salt, the project engineer should check base depth against frost and plan winter care without sand.

Where it fits in Boston

Rowhouse rear yards in the overlay: small Back Bay and South End lots where a recharge system is required and a permeable surface over a stone reservoir can share space with a dry well.
Hospital and university campuses: walks and plazas on large impervious footprints, where the stormwater charge is significant and a documented BMP credit is worth pursuing.
Commercial and multifamily parking courts: lots that now carry an impervious-area charge on every bill.
Courtyards in Article 80 redevelopment: constrained sites that must show retention without giving up usable open space.

If you only want to refresh a sound concrete patio or walk, see our Boston concrete resurfacing page. That is a decorative overlay, not a stormwater practice. Inside the groundwater overlay, ask the Boston Groundwater Trust whether a resurfacing counts as replacement paving under Article 32.

Getting a permeable section through BWSC and city review

BWSC Site Plan Review is the main gate for drainage. In the overlay, BWSC wants plans and calculations for the infiltration system, stamped by a Massachusetts-registered professional engineer, showing that stone void space plus internal storage exceeds the required volume. New or replacement paving in the overlay also needs an Article 32 conditional use permit from the Zoning Board of Appeal, which requires the BWSC approval letter and an engineer's no-harm letter sent to Inspectional Services and the Boston Groundwater Trust. Large projects also pass through the Boston Planning Department's Article 80 review, which includes resilience review inside the coastal overlay.

Resin Rock supplies the system rather than the crew: UV-stable binder, stone blends, trims and the Rock Crete permeable sub-base, with technical data sheets your engineer can cite in the stormwater report. We do not install. Use find an installer and we usually match you with an approved, trained installer within 24 hours. Ask BWSC about credit eligibility before design is fixed, and schedule the infiltration test early.

Before you specify permeable resin-bound in Boston

Check whether the parcel is in the Groundwater Conservation Overlay District; if it is, plan for recharge with no underdrain and an Article 32 zoning approval.
Confirm the BWSC infiltration target, 1 inch or 1.25 inches, from the project's floor area.
Test infiltration and find seasonal groundwater at the reservoir depth, especially near the harbor.
Check Article 25A coastal flood overlay status for waterfront sites.
Ask BWSC before design whether the section can be submitted for a BMP credit.
Write a winter maintenance plan that uses no sand and includes vacuum cleaning.

Common questions about permeable resin-bound in Boston

Will a resin-bound driveway lower my BWSC stormwater charge?

Only if it is part of an engineered system BWSC accepts. The BMP credit covers practices described in the Massachusetts Stormwater Handbook that meet BWSC's retention standard, and porous asphalt is the porous surface it lists by name. A resin-bound section over a stone reservoir would need to be submitted and reviewed. Resurfacing an existing slab does not change your impervious area.

My Back Bay building sits on wood piles. Is a permeable surface enough for the overlay?

Usually not on its own. The overlay requires an infiltration system that captures at least 1 inch of rainfall, with plans and calculations stamped by a Massachusetts engineer, and no underdrain. A permeable resin-bound surface can be the top of that system if the stone reservoir beneath it holds the volume and the soil below accepts the water.

Can I use it on the public sidewalk in front of my house?

Work in the public way needs city approval separate from BWSC, and we have not seen resin-bound listed as an approved sidewalk surface in Boston. Treat it as a private-property surface unless the city tells you otherwise, and check with Boston Public Works before designing anything past your property line.

Official sources for Boston

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 Boston, MA