Pests to know in San Francisco
Termites in San Francisco
UC IPM says the western drywood termite is common along California's Pacific coastal region, and drywood swarmers are usually seen in daytime during summer and fall.[5]
Invasive species reported here
Invasive Aedes mosquitoes (yellow fever and Asian tiger mosquitoes), which bite in daytime and breed in small containers, have spread from Southern California and the Central Valley into the San Francisco Bay Area.[4]
Climate
Central San Francisco (ZIP 94102) is in USDA plant hardiness zone 10b, where the average coldest winter night is 35 to 40°F.[8]
Public agencies that handle pests
- Unusual mosquito activity in San Francisco can be reported to the Department of Public Health's Mosquito Control program at (415) 252-3806 or through 311.[1]
- San Francisco treats street catch basins and storm drains at least monthly to keep them from breeding mosquitoes, and treated basins are marked.[1]
- SFDPH Environmental Health may place mosquito traps on a property for a few days to find the source of a mosquito problem; vermin issues are reported by calling 311.[2]
Local rules and responsibilities
- San Francisco's vector rules are Department of Public Health Director's Rules issued under Article 11, Sections 581–596 of the San Francisco Health Code, covering dwellings, yards, businesses and vacant lots.[1]
- After a tenant reports vermin, San Francisco building owners have 72 hours to investigate and must keep a written log of pest sightings such as rodents, bed bugs, cockroaches and mosquitoes.[2]
- San Francisco's Integrated Pest Management Ordinance, passed in 1996, governs pest control on all City-owned properties and limits products to a Reduced Risk Pesticide List; it does not apply to private property.[3]
Hiring a licensed company
- In San Francisco, property owners or managers must respond to tenant bed bug complaints by hiring a licensed pest control operator; DPH notes treatment can take more than 30 days.[2]
- Only a licensed pest control operator may apply restricted pesticides in San Francisco rentals; the company needs a California Structural Pest Control Board license and must also be licensed to do business in San Francisco.[2]
Free local help
UC IPM, the University of California's statewide pest program, identifies the Argentine ant as the most common ant in and around homes and gardens in California.[7]
Through the year
- Spring to Fall
- In California, subterranean termite swarmers typically fly on warm, sunny days following fall or spring rains; dampwood termites, common in cool coastal areas, also swarm in summer and fall.[6]
Sources
- San Francisco Department of Public Health, “Director's Rules and Regulations for Prevention and Control of Rodents and other Vectors.” media.api.sf.gov/documents/VectorControl_1uauiap.pdf (accessed 2026-10-06)
- San Francisco Department of Public Health, Environmental Health, “Keeping your building free of vermin.” www.sf.gov/information/keeping-your-building-free-vermin (accessed 2026-10-06)
- San Francisco Environment Department, “Pest Management for City Departments.” www.sfenvironment.org/pest-management-for-city-departments (accessed 2026-10-06)
- UC Statewide IPM Program (UC ANR), “Pest Notes: Mosquitoes.” ipm.ucanr.edu/home-and-landscape/mosquitoes/ (accessed 2026-10-06)
- UC Statewide IPM Program (UC ANR), “Pest Notes: Drywood Termites.” ipm.ucanr.edu/home-and-landscape/drywood-termites/ (accessed 2026-10-06)
- UC Statewide IPM Program (UC ANR), “Pest Notes: Termites.” ipm.ucanr.edu/home-and-landscape/subterranean-and-other-termites/ (accessed 2026-10-06)
- UC Statewide IPM Program (UC ANR), “Pest Notes: Ants.” ipm.ucanr.edu/home-and-landscape/ants/ (accessed 2026-10-06)
- USDA ARS and PRISM, via phzmapi.org, “Plant hardiness zone for ZIP 94102 (2023 USDA map data).” phzmapi.org/94102.json (accessed 2026-10-06)
- National Pesticide Information Center, “State Pesticide Regulatory Agencies.” npic.orst.edu/reg/state_agencies.html (accessed 2026-10-06)