Stormwater Pipe Inspection Program

Program Overview

Protecting Our Watersheds Through Proactive Maintenance

The City of Sammamish maintains a complex stormwater network that protects public safety and local waterways. In 2022, the City Council adopted the 2023–2028 Capital Improvement Plan, launching the Storm Pipe Rehabilitation Program — a data-driven effort to identify, inspect, and address aging or at-risk stormwater pipes.

Stormwater System At a Glance 

• 235 miles of pipe

• 64 miles of ditches

• 12,000+ catch basins

• 484 public & 144 private stormwater facilities

Program Goals

• Evaluate the condition of stormwater pipes using CCTV inspections

• Identify and prioritize pipes for repair, rehabilitation, or replacement

• Support risk-based asset management using standardized scoring systems

• Maintain the performance of the City’s stormwater system over the long term

Key Benefits

• Prevents pipe failures and sinkholes

• Reduces flood risk and backups

• Improves maintenance planning and budgeting

• Protects Sammamish’s lakes, streams, and critical areas

Scope of Inspection

• Included:

  • Stormwater conveyance pipes and culverts

  • Pipe segments 8 inches to 48 inches in diameter

  • Prioritized by size, age, and material

• Excluded:

  • Pipes under 8 inches

  • Detention structures

  • Phantom flow/minor drain types