Save the Bay official says stormwater is largest source of plastic and microplastic pollution to San Francisco Bay; outlines local steps

Josh Quigley, policy manager for Save the Bay, told a City of Sunnyvale sustainability speaker series webinar that urban stormwater — the runoff from streets and paved surfaces — is the largest contributor of many pollutants to the San Francisco Bay and a major pathway for plastic and microplastic contamination.

Quigley said the federal Clean Water Act and regional regulators require municipalities to stop discharging trash into waterways and that many Bay Area cities face a regulatory deadline at the end of June 2025 to demonstrate full trash control. “Full trash capture … 0 discharge is the goal under the Clean Water Act,” Quigley said.

The San Francisco Estuary Institute has estimated the Bay receives trillions of microplastic particles annually, Quigley said: “The Bay is actually receiving more than 7,000,000,000,000 microparticles of microplastics every year, and most of that is coming through our storm drain system.” He and other speakers at the webinar outlined three broad approaches cities use to meet the trash-control requirement: install engineered filtration devices that capture pieces down to about 5 millimeters; increase maintenance and street‑level controls such as sweeping and focused litter pickup; and reduce the amount of single‑use plastic entering the system through ordinances and industry changes.

Quigley described examples in Sunnyvale, showing the city’s trash-generation map and how the municipality has used a hybrid approach. He said Sunnyvale reported roughly 94% trash control in its most recent public report and has targeted commercial corridors such as El Camino Real and Middlefield for additional controls. He also noted some high-trash corridors are Caltrans‑owned highways and therefore fall under state, not city, responsibility.

Engineered “full trash capture” systems can be placed at low points in a drainage area to treat a large watershed, Quigley said, and are considered reliable when installed and maintained. He acknowledged those systems are expensive and not always feasible, so cities often supplement with more frequent street sweeping and targeted litter removal. “If there’s not trash on the street, it’s not gonna end up in the storm drain system, and it’s not gonna end up in the bay,” he said.

Quigley emphasized that many pollutants smaller than 5 millimeters — notably microplastics from tire wear and degraded plastic films — will pass through those screens and require additional strategies. He recommended pairing source-reduction policies (for example, limits on single‑use foodware) with nature‑based solutions that filter runoff before it reaches pipes.

Green stormwater infrastructure — bioswales, rain gardens, permeable pavement and similar projects — was presented as a way to achieve multiple outcomes: water quality improvement, microplastic and chemical filtration, reduced localized flooding and neighborhood co‑benefits such as pedestrian safety and urban cooling. “Dirt and plants do a really great job of filtering out microplastics, bacterial, and chemical pollution,” Quigley said, while also noting these green solutions can be costlier up front and require maintenance.

On funding, Quigley pointed to regional and statewide tools that advocates and cities are using. He described the San Francisco Bay Restoration Authority and Measure AA (a regional parcel tax) as sources used for shoreline restoration work; he also said advocates supported a statewide climate resilience bond (referred to at the event as Prop 4) that includes grant funding for stormwater upgrades. He encouraged cities to prepare project lists so they can compete for available grants when funds are released.

Audience questions addressed practical concerns: volunteer opportunities such as California Coastal Cleanup Day and local reusable-foodware campaigns; whether animals can get trapped in capture systems (Quigley explained full-capture devices include an open upstream end and are not intended to entrap animals); whether green infrastructure should use native plants (he and the organization’s habitat staff favor native mixes for longevity and lower maintenance); and the pollution risks of artificial turf, which he said is a significant microplastic and PFAS source.

Quigley and the host highlighted local steps Sunnyvale is taking, including a stormwater strategic plan and pilot green‑infrastructure projects on Persian Drive, Caribbean Drive and safe‑routes‑to‑school projects. He urged residents to participate in county coalitions and city planning processes and to press elected officials to support statewide and local measures that reduce single‑use plastics and fund stormwater upgrades.

Quigley urged a combined approach: “We want to make sure that any investment is meeting multiple benefits,” he said — pairing trash control with climate adaptation and community improvements so local spending achieves several public goals.

The webinar included presentations by Ria Grover, environmental program specialist in Sunnyvale’s Environmental Services Department, who introduced the city’s Climate Action Playbook, and Courtney Jansen, a Sunnyvale sustainability commissioner who hosted and moderated the Q&A.

Looking ahead, Quigley noted the San Francisco Bay Regional Water Quality Control Board has provided compliance flexibility, but cities will need revenue, interagency coordination (including with Caltrans and utilities) and maintenance plans to sustain both engineered capture devices and green infrastructure. Sunnyvale’s ongoing strategic planning and regional grant opportunities were presented as the immediate next steps for local action.