Street Sweeping Program

Overview 

The City of Sammamish’s Street Sweeping Program helps protect water quality, reduce urban flooding, and maintain the integrity of our stormwater infrastructure. Street sweeping is a key requirement under the NPDES Phase II Municipal Stormwater Permit and is included in the City’s annually updated Stormwater Management Program Plan.

By regularly removing leaves, sediment, and debris from streets, prevents pollutants from washing into storm drains and local waterways—like 6PPDQ. 6PPD is a chemical that prevents automotive tires from degrading (i.e., breaking down) and helps them last longer. When 6PPD is exposed to air, it reacts with ozone to create 6PPD-quinone (also known as 6PPDQ). 6PPDQ is lethal to coho salmon and can contaminate water systems.

Current Operations 

• Coverage: ~60 miles of arterial roadways and ~220 miles of local access roads.

• Priority Areas: Arterials are swept more often due to higher traffic and pollutant levels; neighborhood streets are swept less frequently due to lower traffic and physical obstructions such as parked cars and vegetation.

• Seasonal Schedule: More frequent sweeping in fall and winter to manage leaf drop and storm debris.

• Equipment: Rear broom and air vacuum sweepers. Collected material is taken to a designated yard before disposal at a landfill.

• Monitoring: Pollutant load reductions (e.g., phosphorus, nitrogen) are estimated using established calculation tools.

• Implementation: Street sweeping services are performed by ProVac under a multi-year contract through the end of 2024, with the option to renew.

Street Sweeping Schedule 

The City sweeps public streets on a regular basis to help keep our roads and waterways clean. Street sweeping schedules and priorities may shift depending on severe weather conditions, traffic incidents or construction, or emergencies. Please note that moving, raking, or blowing leaves and debris into the street is not allowed. It slows down the street sweepers, can create hazardous driving conditions, and can clog our storm drains.

Main Arterials

Neighborhood Streets

Map of the Current Street Sweeping Program

Benefits of the New Sweeper 

• Enhanced Cleaning Power: More efficient pollutant removal, helping protect streams, lakes, and salmon habitat.

• Faster Spill Response: Owning a sweeper allows the City to respond quickly to emergency spills and resident requests.

• More Frequent Sweeping: Increased coverage of arterials and neighborhood streets.

• Cost Savings: Reduced reliance on contracted services and better control over scheduling.

• Measurable Impact: Ability to track volume and type of debris collected for water quality benefit reporting.

2025/2026 Program Enhancements 

The City’s Enhanced Maintenance Plan will expand sweeping efforts in:

• High-traffic corridors

• Leaf-heavy canopy areas

This proactive approach will help:

• Meet and exceed National Pollutant Discharge Elimination System (NPDES) permit requirements

• Protect water quality and wildlife habitat

• Improve the cleanliness and appearance of City streets