Across Riverside and the Inland Empire, permeable resin-bound surfacing may be proposed as the wearing course of a permeable pavement BMP in a project's Water Quality Management Plan (WQMP), on an infiltration base the local agency accepts. County guidance names pervious asphalt, pervious concrete and modular block, so the approving city decides whether resin-bound is accepted. Inland soils on the alluvial fans below the mountains often drain better than coastal clays, which can make infiltration more realistic here.

The first job is working out which rules apply. Riverside County alone spans three regional water boards, San Bernardino County cities follow their own technical guidance, and the Santa Ana Region is moving to a single regional MS4 permit in March 2027.

Three watersheds, two counties and a new regional permit

Riverside County Watershed Protection organizes land development guidance by watershed: the Santa Ana River watershed, including the cities of Riverside, Corona, Moreno Valley and Jurupa Valley; the Santa Margarita watershed around Temecula and Murrieta, regulated by the San Diego Regional Board; and the Whitewater River watershed in the Coachella Valley, under the Colorado River Basin Regional Board. Each has its own WQMP guidance, and the Riverside County Flood Control and Water Conservation District publishes LID BMP Design Handbooks for all three.

San Bernardino County cities in the Santa Ana watershed, including San Bernardino, Ontario, Rancho Cucamonga, Fontana and Redlands, use the county's Technical Guidance Document for WQMPs. It lists permeable pavement among infiltration BMPs and sizes retention from field-measured infiltration divided by a safety factor.

In the Santa Ana Region, Order No. R8-2026-0034 was adopted on September 11, 2026 and takes effect March 10, 2027, replacing the separate Riverside and San Bernardino county permits. It defines priority projects to include new development of 10,000 square feet or more of impervious surface, significant redevelopment of 5,000 square feet or more, and parking lots adding 5,000 square feet or more. It also limits hydrologic change: for the 2-year, 24-hour storm, post-project runoff volume generally may rise no more than 10 percent unless another listed condition is met. These project rules start later than the permit itself: current WQMP guidance keeps applying to new applications until 90 days after the Water Board approves the uniform guidance documents due by March 10, 2029.

Alluvial fans, heat and groundwater basins

Soils change quickly across the region. Sandy and gravelly alluvial fan deposits below the San Gabriel and San Bernardino mountains can infiltrate readily, while valley-floor clays and shallow bedrock elsewhere cannot. Infiltration testing, with a safety factor applied as the county guidance requires, should set the design rate, and the permeable section's stone reservoir is sized from that tested rate.

Groundwater is a water supply here, so infiltration has to protect it. Sites near former industrial uses, fuel tanks or known plumes may need a liner, and the agency can require a site-specific study. Summer heat and Santa Ana winds bring dust and debris that settle into permeable surfaces, so the maintenance plan should include vacuum sweeping before the first storms of the season.

Inland Empire projects that suit permeable resin-bound

Office frontages, employee plazas and car parking at logistics campuses, kept separate from heavy truck courts.
Paseos, pool decks and walkways in newer master-planned communities across western Riverside and southwest San Bernardino counties.
Courtyards and sidewalks around historic buildings in downtown Riverside and Redlands.
Winery terraces in the Temecula Valley and resort patios in the Coachella Valley, each under its own regional board.

Specifying permeable resin-bound for local WQMP approval

Confirm the watershed and approving city first, then follow that area's WQMP guidance and county LID handbook. The project WQMP should show the permeable area as an infiltration BMP, with test results, reservoir depth and an operation and maintenance agreement. County fact sheets treat permeable pavement as an infiltration design that needs at least 10 feet to historic high groundwater. Where infiltration is not allowed, ask the approving city whether a lined section earns any credit or whether another BMP is needed.

Resin Rock supplies UV-stable resin binder, natural stone aggregate blends, trims and the Rock Crete permeable sub-base; we do not install. Engineers can use our technical data sheets for the submittal, and installers across the Inland Empire can apply for California installer training. Owners who need a contractor can ask us for an approved installer, usually matched within 24 hours.

Before you specify permeable resin-bound in the Inland Empire

Identify the watershed: Santa Ana, Santa Margarita or Whitewater River.
Use the right WQMP guidance for Riverside or San Bernardino County.
Test infiltration and apply the required safety factor before sizing the reservoir.
Screen for contamination or groundwater plumes that call for a liner.
Ask the approving city which WQMP guidance applies on your application date.
Plan vacuum sweeping before the rainy season.

Common questions about permeable resin-bound in the Inland Empire

Which stormwater rules apply to my project in Riverside County?

It depends on the watershed. The Santa Ana River watershed, including the City of Riverside, follows Santa Ana Regional Board rules; the Santa Margarita watershed around Temecula follows the San Diego Regional Board; and the Coachella Valley follows the Colorado River Basin Regional Board. Riverside County Watershed Protection publishes WQMP guidance and LID handbooks for each.

Is permeable pavement an accepted BMP in the Inland Empire?

Yes. San Bernardino County's Technical Guidance Document lists permeable pavement among infiltration BMPs, and Riverside County's LID BMP Design Handbooks cover infiltration BMPs for its watersheds. Acceptance still depends on infiltration testing, site constraints and review by the city that approves your WQMP, so the resin-bound wearing course should be named clearly in the submittal.

Can I resurface my old concrete with resin-bound and call it permeable?

For appearance, yes. For a WQMP or any runoff reduction, no. Water passes through the resin layer and then runs off the concrete underneath, so nothing infiltrates and nothing is stored. A qualifying section removes the slab and places the surface on a permeable base such as Rock Crete over an engineered stone reservoir.

Official sources for the Inland Empire

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 Riverside / Inland Empire, CA