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Construction and development activities can disturb soil, increase erosion, and carry pollutants into nearby properties, storm drains, and local streams. Proper Erosion Prevention and Sediment Control (EPSC) measures help protect water quality and reduce sediment leaving a site.
All development activity within the WES service area must follow EPSC requirements. Projects that disturb 800 square feet or more must obtain a WES EPSC Permit. Projects disturbing 1 acre or more anywhere in Clackamas County must also obtain a Department of Environmental Quality (DEQ) 1200-C or 1200-CN Construction Stormwater Permit.
Types of EPSC Permits
The permit you need depends on your project’s size and location. Below is a summary of each permit type.
| Disturbance Area | Permit Type(s) Needed |
| Gladstone, Rivergrove, and applicable WES service areas (excluding Happy Valley) | |
| 800 sq. ft. to less than 1 acre of disturbance (thru all phases) |
|
| 1 acre to less than 5 of disturbance (thru all phases) |
|
| 5 acres or more of disturbance (thru all phases) |
|
| All other areas in Clackamas County | |
| 1 acre or more of disturbance (thru all phases) |
(Check with DEQ) |
WES EPSC Permit
Required for:
- Projects disturbing 800 sq. ft. or more within the WES service district (excluding Happy Valley)
Typical for:
- Single-family homes
- Small commercial or industrial improvements
To apply:
- Submit the WES EPSC Permit Application and required plans
DEQ 1200-CN Permit
Required for:
- Projects disturbing 1 acre to <5 acres
- Located in Gladstone, Rivergrove, or WES service areas (excluding Happy Valley)
- Issued by WES along with the local EPSC permit.
Typical for:
- Small subdivisions and partitions
- Multi-family construction
- Commercial and industrial projects
To apply:
- Submit the WES EPSC Application or 1200-CN Templates and erosion control plans for WES review.
DEQ 1200-C Permit
Required for:
- Projects disturbing 5 acres or more
- Applies within WES service areas, Gladstone, or Rivergrove
- In Happy Valley, this permit is required in addition to the city’s EPSC permit
Typical for:
- Large subdivisions
- Multi-family developments
- Commercial and industrial sites
To apply:
- Submit the DEQ 1200-C application and template-style erosion control plan directly to DEQ.
- Templates available on DEQ’s 1200-C Construction Stormwater webpage.
EPSC Resources
Planning and Design Manual
The Erosion Prevention and Sediment Control Planning and Design Manual and Best Management Practices Drawings provides detailed information about EPSC practices, materials, and installation guidelines. It was developed in partnership with multiple Clackamas County jurisdictions and Clean Water Services.
Training
EPSC training is available from private providers. WES does not endorse or recommend any specific training company.
EPSC Inspections
Inspections help ensure EPSC measures are in place and functioning throughout construction.
Initial Inspection
Required before:
- Single-family homes: Before pouring foundation or footings
- Commercial, industrial, and multi-family: Before any soil disturbance (except installing EPSC measures)
Schedule:
- Single-family: Call 503-742-4720
- Code 201 – Initial EPSC inspection
- Code 297 – Final EPSC inspection
- Commercial / Multi-family / Industrial: Call WES at 503-742-4567 and request a development representative
Ongoing Monitoring
WES will conduct periodic inspections during construction.
Final Inspection
Requested once the site has been permanently stabilized.
