Videos show flooding after an intense storm in the city earlier this year.
The city's civil grand jury released a report detailing how an increase in atmospheric rivers, combined with the city's vulnerable infrastructure, will overwhelm low-lying neighborhoods.
MORE: SF and major coastal cities 'sinking' amid rising sea levels, report says
That includes SoMa, the inner Mission, Civic Center and the Western Addition.
The report also highlights "poor communication" across city departments that will severely affect those areas.
Our media partner the SF Standard writes that city leaders have two months to publish a formal response to the report.