BAY AREA • HOUSEHOLD FIELD GUIDE

Storm ready,
San Francisco.

Street flooding, basements & sewer backups. Local steps and official sources for the place you call home.

Sources reviewed October 24, 2026 · Preparation guide

Making a decision today?

Check current forecasts, warnings and local instructions. This guide does not display live alerts or verify road access, shelters or supply stock.

NWS Bay Area forecasts & alerts

01 / KNOW YOUR EXPOSURE

Street flooding, basements & sewer backups

San Francisco’s combined stormwater and sewage system can be overwhelmed during intense rain. Low entrances, garages and basements need attention even away from the waterfront. Coastal high tides are a separate hazard.

Read the map correctly

SFPUC’s 100-Year Storm Flood Risk Map concerns stormwater runoff. It is not a coastal flood forecast or a complete map of all flooding.

Official local map guidance FEMA effective flood-map address lookup

Maps cannot rule out flooding outside a mapped zone. No individual parcel has been assessed for this guide.

02 / BEFORE THE RAIN

Your household checklist

Check items for this visit, then use your browser’s print command for a paper copy.

Move important belongings above garage and basement floor level.
Review sewer lateral maintenance with a qualified professional if backups are a concern.
Keep leaves and litter away from private drains; report street flooding or sewer issues to 311.
Prepare drinking water, food, medications, lights, charged devices and important documents.
Agree on a meeting place and help for children, older adults, pets and access needs.
Safely clear private gutters and drains before storms. Stay out of channels; report public blockages.

San Francisco official preparation guidance

03 / PROTECT LOW ENTRANCES

Sandbags: check before you go

Public Works publishes up to 10 bags per resident or business address before and during severe rainstorms, with proof of address. Published pickup: Marin/Kansas gate, Monday–Saturday, 8 a.m.–2 p.m. Expect self-loading; confirm exceptions, hours and stock.

Confirm current activation, eligibility, stock and hours before travel. Sandbags can help redirect shallow runoff; they do not make a building floodproof or replace evacuation.

Official sandbag program & locations

04 / STAY CONNECTED

Alerts & local reporting

Flooding and sewer issues: SF311. Immediate life danger: 911.

Official city storm contactsCall 911 for immediate danger to life.

When a storm arrives

Follow official evacuation instructions. Stay out of floodwater, never drive around barricades, and avoid downed wires. Do not enter unsafe drainage channels or attempt storm-time roof or gutter work. Check actual closures before traveling.

A local question

Is the SFPUC map the same as a coastal flood advisory?

No. The map models stormwater risk; a coastal advisory describes a particular forecast period and shoreline geography. Read both if your property has both exposures.