Permeable resin-bound surfacing can work as a stormwater practice in Asheville only when it is built as a complete permeable pavement system: the porous wearing course over an open-graded stone reservoir, designed by an engineer to North Carolina's permeable pavement criteria and accepted by the City. On Asheville's hillsides that usually means terracing the base in level steps instead of following the slope.
Laid over an old concrete driveway or asphalt lot, the surface still drains through its top layer, but the water then runs off the slab underneath. Treat that as a surface upgrade, not a stormwater control. The notes below are for designers and owners working in the French Broad and Swannanoa watersheds as the city rebuilds after Tropical Storm Helene.
How Asheville and North Carolina treat permeable pavement
Asheville operates under a state-issued NPDES stormwater permit (NCS000435) that the City says was renewed on January 1, 2021 and runs through December 31, 2026, with post-construction runoff control as one of its required program elements. Local rules sit in Section 7-12-2 of the City code, and engineering and stormwater permits are handled by the Traffic Engineering and Stormwater Services Divisions through the Permits Application Center.
Design criteria come from the NCDEQ Stormwater Design Manual, Chapter C-5. It names permeable interlocking concrete pavers, pervious concrete and porous asphalt as the common surfaces and says a designer proposing any other surface must show it performs hydraulically and structurally over the long term. The finished surface must demonstrate an infiltration rate of at least 50 inches per hour. Infiltrating systems built to the criteria may be counted as 100 percent pervious when calculating built-upon area, which can keep a project below a density threshold. That is an argument your engineer makes to the reviewer, not an outcome anyone can promise.
The City also bills a stormwater fee on impervious area. For July 2026 to June 2027, single-family tiers are $4.87, $7.76 or $10.69 a month, and other properties pay $7.76 per ERU of 2,442 square feet. City Code Section 7-12-6 lets properties other than detached single-family homes apply for fee credits of up to 60 percent for measures that go beyond the minimum rules, renewed each year. Ask Stormwater Services for the current credit policy before counting on one.
Slopes, thin soils and flood history: what the base design must answer
C-5 limits the soil subgrade under permeable pavement to a 2 percent slope and allows terraces, baffles or graded berms to hold water at different elevations, shown on a separate subgrade grading plan. On a ridge or cove lot, the engineer will step the stone reservoir down the hill rather than drape one section over existing grade.
Mountain soils here range from deep weathered material to thin cover over rock, and old fill can lose strength when saturated. The state guidance points designers to a detention design, with an underdrain or liner, where soils are unstable when wet, shrink and swell, or drain slowly. Infiltrating systems need a site-specific soil investigation, and the subgrade has to be graded when it is dry. Winter freeze-thaw cycles are another reason to keep the reservoir draining rather than holding water near the surface.
Helene changed the starting point for many owners. The City's Public Works recovery program covers nearly 200 damaged sites, including landslides and stormwater infrastructure. Permeable surfacing is not flood protection, and on slide-prone or recently disturbed slopes a geotechnical engineer should decide whether adding infiltration is appropriate at all. In mapped floodplains, rebuilding requires a floodplain permit first.
Where permeable resin-bound fits in Asheville
- Terraced parking pads and walks on hillside lots in Montford, Kenilworth or West Asheville, where a stepped base can take roof and drive runoff that now sheets into the street.
- Brewery, restaurant and hotel patios downtown and on the South Slope, replacing worn concrete with a drained, decorative finish.
- Infill multifamily and mixed-use courtyards that need to stay under a built-upon area threshold, using the C-5 pervious credit as a design option.
- Campus and institutional paths with light pedestrian loads and a maintenance plan someone will actually follow.
Getting a permeable section through Asheville review
Expect two early conversations: one with your engineer about whether the site can infiltrate at all, and one with Stormwater Services about how a resin-bound wearing course will be evaluated, since it is not among the surfaces C-5 lists by name. Bring a soil report, the reservoir and subgrade design, observation well locations, a plan for the post-construction surface infiltration test, and an owner maintenance plan. Where infiltration is not feasible, expect an underdrained detention design instead.
Resin Rock does not install. We manufacture and supply the UV-stable binder, stone blends, trims and the Rock Crete permeable sub-base, publish technical data sheets your engineer can attach to a submittal, and train and approve installers. Once the design is settled, request an approved installer and we usually make a match within 24 hours.
Before you specify permeable resin-bound in Asheville
- Ask Asheville Stormwater Services how a surface not named in NCDEQ C-5 will be reviewed.
- Order a site-specific soil investigation and choose infiltration or underdrained detention early.
- Terrace the subgrade so each cell stays at or below a 2 percent slope.
- Have a geotechnical engineer assess slide risk on steep or Helene-affected slopes.
- Confirm floodplain status and permits before any rebuilding near a river or creek.
- Write a maintenance plan that covers vacuum sweeping and surface infiltration testing.
Common questions about permeable resin-bound in Asheville
Will a permeable resin-bound driveway lower my Asheville stormwater fee?
Not automatically. Asheville bills single-family properties in three tiers by impervious area, and the City Code's fee credit provision covers other properties, not detached homes. If an engineered, infiltrating section reduces your measured impervious area, ask Stormwater Services whether your tier can be reviewed. An overlay on existing concrete changes nothing, because the slab underneath is still impervious.
Can it go on a steep Asheville lot?
Often, but not as one sloping section if it is meant to manage stormwater. North Carolina's criteria cap the subgrade at 2 percent, so engineers terrace the base with baffles or berms and size each cell separately. Steep drives usually keep a conventional surface on the steepest run, with permeable sections on the flatter landings and parking areas.
Does permeable surfacing help with flooding like Helene?
No. A permeable surface helps with the frequent, smaller storms that cause runoff and erosion around buildings, and it can reduce what leaves a lot. It cannot hold back river flooding of the kind Helene brought along the French Broad and Swannanoa. Properties in mapped floodplains need a floodplain permit before rebuilding, and the City's Flood Assistance Support Team can explain the options.
Official sources for Asheville
- NCDEQ Stormwater Design Manual (Chapter C-5, Permeable Pavement)
- City of Asheville: Stormwater Fees
- City of Asheville: Apply for a Stormwater Permit
- City of Asheville: Flood Assistance Support Team (FAST)
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.