(a) As San Francisco has grown, its hilly topography has been paved over, and naturally formed historic waterways have been incorporated into the City’s combined sewer and stormwater collection system that routes both overland runoff and sanitary sewage to the City’s treatment plants.
(b) During intense storms, when there is more rain than the collection system is designed to handle, certain areas of the City are subject to flood risk from stormwater. The location of these flood-prone areas generally aligns with the City’s historic waterways and areas that are built on landfill.
(c) Flooding in these areas can result in property damage which negatively impacts affected residents and businesses.
(d) The San Francisco Public Utilities Commission performed a technical analysis to develop a 100-Year Storm Flood Risk Map that identifies those parcels in San Francisco that are at risk of deep and contiguous flooding during a storm with a 100-year return period, meaning a storm having a 1% chance of occurring in a given year.
(e) It is in the public interest to ensure that owners of real property at risk of deep and contiguous flooding from stormwater have accurate information about the flood risk so they can take steps to mitigate the risk.
(f) For that reason, and also to ensure fairness in real property transactions, it is also in the public interest to ensure that people are aware of stormwater flood risks before buying or renting real property. Mandatory disclosure at the point of sale, or before signing a lease, is an effective tool for ensuring that buyers and tenants of real property have access to this information.
(Added by Ord. 35-19, File No. 181108, App. 3/8/2019, Eff. 4/8/2019)