Hillsboro, OR Environmental Rules: Stormwater Management (2026)
Key Facts
- Applies to
- Aboveground stormwater facilities on new development
- Technical standard
- 2018 CWS Design & Construction Standards
- Design requirement
- Integrated grading and compatible landscaping
- Reviewed at
- Type II/III land use approval
- Regional authority
- Clean Water Services, Washington County
Summary
New Hillsboro development with aboveground stormwater facilities must integrate them into site design and meet Clean Water Services' regional runoff treatment standards.
The Review Authority may condition any Type II or Type III land use application approval to require that the aboveground stormwater facility complies with the applicable provisions of the 2018 CWS Design and Construction Standards Chapter 3 Sensitive Areas and Vegetated Corridors and Chapter 4 Runoff Treatment and Control.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 1 | Community Development Code: Supplement 1).
Full Breakdown
Hillsboro's Community Development Code requires aboveground stormwater facilities on qualifying development sites to be designed with coordinated finished grading and compatible landscaping so they read as part of the site rather than bolted-on infrastructure. The Review Authority may condition Type II or Type III land use approvals on compliance with the 2018 Clean Water Services Design and Construction Standards, Chapter 3 (Sensitive Areas and Vegetated Corridors) and Chapter 4 (Runoff Treatment and Control). CWS being the Washington County regional agency that sets the actual technical stormwater treatment and quantity standards Hillsboro incorporates by reference.
Violations & Fines
Land use applications that omit required stormwater facility plans, or facilities that don't meet the incorporated CWS design standards, can be denied or held up with conditions before the project is approved.
Frequently Asked Questions
Who actually sets Hillsboro's stormwater treatment standards?
Does this rule apply to a typical single-family home?
Sources & Official References
Other rules in Hillsboro
Compare Hillsboro to another location·View the Oregon environmental rules overview
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Stormwater Management in Nearby Cities
How other cities in Washington County handle stormwater management.