Permeable resin-bound surfacing can earn stormwater value in Alexandria when it is built as permeable pavement over a gravel base that stores rain, which is the practice the City's Stormwater Utility credit describes. If the City accepts the surface, the permeable pavement credit is worth up to 20% of a property's fee, and on a redevelopment site the plan reviewer decides whether it can count toward Virginia's phosphorus reduction targets.

Over an existing concrete patio or asphalt lot, the same surface is decorative: water passes the resin-bound layer and then runs off the slab toward Four Mile Run, Cameron Run or the Potomac. Here is how the City's credit and Virginia's rules work, what Alexandria's ground means for the base, and where the system fits from Old Town to the West End.

Alexandria's utility fee credit and Virginia's phosphorus rules

Alexandria adopted its Stormwater Utility Fee in 2017, billed on the real estate tax bill and based on impervious area. The Stormwater Utility Credit Manual approved in November 2022 lets owners combine credits to cut the fee by up to 50%, with permeable pavement worth up to 20% on both the residential and non-residential menus. Applications are accepted from December 1 to February 15, and approved credits apply to the next two years of fees.

The current Credit Manual describes permeable pavement as a surface with enough gaps for rain to reach a gravel base layer, where it gradually soaks into the ground, and names interlocking paver blocks as the typical residential type. The City's self-certification guide for permeable pavement lists porous concrete, asphalt or pavers over a washed-stone reservoir. BMPs must meet City-recognized design standards, generally the Virginia BMP Clearinghouse specifications. A resin-bound surface is not one of the named types, so the Stormwater Management Division decides whether and how it would be credited.

For development, Virginia's Erosion and Stormwater Management Regulation requires redevelopment with no net increase in impervious cover to cut total phosphorus at least 20% below the predevelopment load where an acre or more is disturbed, and at least 10% where less is disturbed. Permeable pavement is among the practices in the Virginia Stormwater Management Handbook approved for meeting those reductions. The Handbook's specification names pervious concrete, porous asphalt, grid pavers, interlocking concrete pavers and artificial turf, so the plan reviewer decides whether a resin-bound surface fits it.

Coastal Plain clays, waterfront fill and recurring flooding

Alexandria sits almost entirely on Coastal Plain sediments of sand, pebbles, mud and silt, and the City flags marine clay soils, which drain slowly and shrink and swell, as a concern in parts of the city. The Handbook's permeable pavement specification says Hydrologic Soil Group C and D soils usually need an underdrain, that a design meant to infiltrate without one needs a field-verified rate of at least 0.5 inch per hour, that permeable pavement should never sit on fill unless it has an impermeable liner and underdrain, and that it should not be installed over soils with high shrink or swell potential, so test the subgrade early. Much of the Old Town waterfront is made ground, so lined sections are the realistic default there.

The Handbook also requires at least 2 feet between the bottom of the reservoir and the seasonally high water table. Near the Potomac and in low parts of Old Town, shallow groundwater can make that hard to meet, and the City runs Flood Action Alexandria to address recurring flooding. Freeze-thaw winters are one more reason to keep the reservoir free-draining.

From Old Town rowhouses to West End condominiums

Rear patios and garden paths in Old Town, where a stone finish suits historic streets and visible work goes through historic district review.
Driveways and parking pads in Del Ray, Rosemont and Seminary Hill, where the residential menu offers a flat 20% permeable pavement credit if the City accepts the surface.
Condominium association walkways and courtyards, where the association applies for credits on behalf of owners.
Plazas in Carlyle, Potomac Yard and Eisenhower Valley, where redevelopment phosphorus targets have to fit dense sites.
Church, school and nonprofit lots, which pay the fee even when tax-exempt.

Review by Alexandria's stormwater staff, and supply from Resin Rock

Development plans go through the City's site plan process, with Transportation and Environmental Services stormwater staff reviewing water quality and quantity under the state regulation. Credit applications go to the Stormwater Management Division during the December to February window. Bring reservoir details, underdrain details if the design uses one, infiltration data, and the maintenance commitment the City expects, including at least annual vacuum sweeping.

As a manufacturer-supplier, Resin Rock doesn't do installations. We supply UV-stable binder, natural stone blends, trims and Rock Crete permeable sub-base, with technical data sheets for your reviewer, and we train and approve installers. Use find an installer for a match, usually within 24 hours, or see our Virginia installer training if you install.

Before you specify permeable resin-bound in Alexandria

Design a washed-stone reservoir that matches the City's credit description, and add an underdrain where the soils call for one.
Ask the Stormwater Management Division how a resin-bound surface will be reviewed, since the City's documents name pavers, porous concrete and asphalt.
Treat waterfront fill as liner-and-underdrain ground, and test for marine clay elsewhere.
Confirm 2 feet of separation to the seasonally high water table.
Apply for credits between December 1 and February 15.
Plan at least annual vacuum sweeping and keep sand and salt off the surface.

Common questions about permeable resin-bound in Alexandria

How much can permeable pavement reduce my Alexandria stormwater fee?

Permeable pavement is worth up to 20% under the City's credit menu, and combined credits can reach 50%. Approved credits apply to the next two years of fees, and applications are taken from December 1 to February 15. The City's credit describes a permeable surface over a gravel base that stores rain and lets it soak in, so an overlay on existing concrete won't qualify, and the City decides whether a resin-bound surface counts.

Does a resin-bound surface qualify for Alexandria's credit?

Not automatically. The City's self-certification guide lists porous concrete, asphalt and pavers, and BMPs must meet City-recognized design standards. A resin-bound wearing course over a compliant reservoir may be considered, but the Stormwater Management Division decides. Get its view in writing before you build if the credit matters to your budget.

How do I keep the credit once it's approved?

Inspect the surface each year and keep it working. The City's guide asks owners to keep the pores free of debris, vacuum sweep at least once a year, check that a bucket of water soaks in rather than ponding, and shovel snow instead of spreading sand or salt. Homeowners self-certify that the practice functions when applying.

Official sources for Alexandria

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 Alexandria, VA