Permeable Resin-Bound Surfacing in Bend, OR

Bend's DEQ permit and the 5,000 square foot trigger

Bend operates under an individual Phase II municipal stormwater permit from the Oregon Department of Environmental Quality, the only individual Phase II permit DEQ currently lists. Its stormwater drains toward the Deschutes River, sections of which are on DEQ's 2018/2020 impaired waters list for turbidity and sedimentation and for pH.

The permit lowers the post-construction threshold for new development and redevelopment to 5,000 square feet of new or replaced impervious surface. Bend has updated its rules to match (Bend Code Chapter 16.15, Ordinance NS-2538), and since January 1, 2026 residential building permits that create or replace 5,000 square feet need a stormwater drainage plan and a maintenance agreement. DEQ's evaluation notes that retention-based green infrastructure is effective at reducing the pollutants behind those Deschutes listings, which favors facilities that hold water on site.

Infiltration has a second regulator. DEQ encourages it, but the stormwater permit does not authorize discharges to underground injection control (UIC) systems such as drywells, which are the most common UIC type in Oregon and need their own coverage under OAR 340-044. A permeable section that infiltrates through its base into native soil is a different design from one that feeds a drywell, and the difference matters at review.

Volcanic ground, freeze-thaw and cinders: what the base must handle

Bend's soils are typically thin layers of pumice, ash and sandy material over fractured basalt. Some areas drain very fast and others hit rock close to the surface, so infiltration testing and a look at depth to bedrock come first. Fast-draining ground is good for a permeable section but also gives pollutants a short path to groundwater, which is why DEQ watches how water enters the subsurface.

Winter is the design driver. The base has to drain before it freezes so water does not sit in the section through freeze-thaw cycles, and snow removal should avoid steel blades that can damage the surface. Winter traction material on nearby roads and driveways is the biggest clogging risk for any permeable surface in Central Oregon, so plan for vacuum sweeping each spring and keep plowed piles of grit off the permeable area. A resin layer over an existing concrete slab gives none of these benefits: meltwater still runs off the slab.

Bend projects where it fits

• Patios, walkways and hot tub surrounds at homes on the west side and in newer neighborhoods.
• Courtyards and outdoor seating in the Old Mill District and downtown, where snowmelt management matters for winter use.
• Brewery, restaurant and resort terraces that need a finish that drains quickly after snow.
• Small multifamily and mixed-use projects reaching the 5,000 square foot trigger, where a permeable surface reduces runoff to other facilities.

Getting a permeable resin-bound section approved in Bend

Ask the City of Bend's engineering and stormwater staff which design standards apply, then submit infiltration test results, depth to bedrock or groundwater, the section and any overflow route, and a winter maintenance plan. If the design uses a drywell or other subsurface injection, confirm UIC registration or permit coverage with DEQ before construction.

Resin Rock manufactures and supplies resin-bound systems and does not install. We supply UV-stable binder, natural stone aggregate blends, trims and the Rock Crete permeable sub-base, with technical data sheets for review, and Central Oregon contractors can apply for our Oregon installer training. Owners can ask us for an approved installer, usually matched within 24 hours.