SFPUC unveils draft 100‑year storm flood‑risk map; staff to seek feedback and propose disclosure law

San Francisco Public Utilities Commission staff presented a draft citywide flood‑risk map July 24 showing parcels likely to be subject to flooding in a 100‑year design storm. The map, based on a validated hydrologic and hydraulic model that incorporates city drainage infrastructure and projected sea‑level rise through 2050, highlights deep flooding (>6 inches) and contiguous flood areas.

Wastewater staff described the modeling workflow, noting use of the watershed urban assessment model, ground‑surface and imperviousness data, and an approach that defines contiguous flooding as greater than half a block. Staff said about 4,000 property owners within the draft map area were sent notification letters, and the map and supporting FAQs are available at sfwater.org/floodmaps for address searches.

"The purpose of the map is to inform prospective buyers and renters about stormwater flood risk so that they can make informed decisions about investments or preparedness on their property," staff said, and added the next steps are to finalize the map in August, establish a request‑for‑review process for contested parcels and return to the commission in September before proposing legislation requiring disclosure on sale or lease.

Public commenters described repeated flooding in particular neighborhoods and asked for more neighborhood meetings and advance review of proposed disclosure language. Staff said the request‑for‑review will include site visits and objective, repeatable criteria for appeals.

Next steps: staff intends to finalize the map, publish a review procedure and propose legislative steps to require disclosure to buyers/lessees; community outreach and hearings will continue.