Tigard, OR Environmental Rules: Stormwater Management (2026)
Key Facts
- Permit condition
- Adequate provisions for stormwater and floodwater runoff
- System design
- Storm drainage separate from any sanitary sewerage system
- Culverts
- Sized for runoff from the entire upstream drainage area
- Governing rules
- Clean Water Services requirements adopted in Chapter 12.02
- Penalty
- Each day a separate violation; civil infraction, no jail
- Size approval
- City Engineer approves facility size
Summary
In the City of Tigard, Oregon, the Director and City Engineer issue a development permit only where adequate provisions for stormwater and floodwater runoff have been made. Storm drainage must be separate from the sanitary sewer, culverts must handle the entire upstream drainage area, and Clean Water Services rules are adopted as part of the city code.
§ 18.910.100. Storm Drainage. ... A. General provisions. ... The Director and City Engineer shall issue a development permit only where adequate provisions for stormwater and floodwater runoff have been made, and: 1. The storm water drainage system shall be separate and independent of any sanitary sewerage system; ... C. Accommodation of upstream drainage. A culvert or other drainage facility shall be large enough to accommodate potential runoff from its entire upstream drainage area, whether inside or outside the development, and the City Engineer shall approve the necessary size of the facility, based on Clean Water Services requirements. D. Effect on downstream drainage. Where it is anticipated by the City Engineer that the additional runoff resulting from the development will overload an existing drainage facility, the director and engineer shall withhold approval of the development until provisions have been made for improvement of the potential condition or until provisions have been made for storage of additional runoff caused by the development in compliance with Clean Water Services requirements.
Full Breakdown
Section 18.910.100 of the Tigard Municipal Code ties every development permit in the City of Tigard, Oregon to stormwater capacity. The Director and City Engineer issue a development permit only where adequate provisions for stormwater and floodwater runoff have been made. The storm water drainage system must be separate and independent of any sanitary sewerage system, inlets must be provided where possible so surface water is not carried across any intersection or allowed to flood any street, and surface water drainage patterns must be shown on every development proposal plan. Where a development is traversed by a watercourse, drainageway, channel or stream, a stormwater easement or drainage right-of-way must follow the lines of the watercourse with enough further width for conveyance and maintenance.
A culvert or other drainage facility must be large enough to accommodate potential runoff from its entire upstream drainage area, whether inside or outside the development, and the City Engineer approves the necessary size based on Clean Water Services requirements. Where the City Engineer anticipates that added runoff will overload an existing drainage facility, the director and engineer must withhold approval until improvements are provided or storage of the additional runoff is provided in compliance with Clean Water Services requirements.
Chapter 12.02 supplies the operating rules. Section 12.02.040 adopts Clean Water Services Resolution and Orders No. 91-47 (excluding Chapter 2), covering construction standards for sanitary sewerage and storm and surface water management systems, and § 12.02.050 adopts Clean Water Services Ordinance Nos. 26 through 28. Under § 12.02.080 the city manager can adopt amendments for no longer than 90 days without council action, and the council must adopt them before expiration to keep them in effect.
Violations & Fines
Under § 12.02.100, each day a violation of Chapter 12.02 is committed or permitted to continue is a separate violation, and a finding is a civil infraction under Chapter 1.16 that can be prosecuted in the municipal court. A violation does not result in imprisonment or a jury trial, and the fine does not relieve the responsible party of the duty to abate. The code enforcement officer can require immediate remedial action under § 12.02.090, and officers of a firm or corporation answer for its violations.
Frequently Asked Questions
Does a development in Tigard need a stormwater plan before a permit is issued?
Whose stormwater standards does the City of Tigard follow?
What happens if a new development would overload an existing drain in Tigard?
What is the penalty for violating the Tigard sewer and surface water chapter?
Who counts as a responsible party under Tigard's surface water rules?
Sources & Official References
Other rules in Tigard
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Stormwater Management in Nearby Cities
How other cities in Washington County handle stormwater management.