Showcase · Data layers · DataSF and California open data

How far has the soft-story program got?

San Francisco requires wood-frame apartment buildings built before 1978, with five or more homes and two or more storeys over a weak ground floor of garages or shops, to be strengthened against earthquakes.

How far has San Francisco’s soft-story retrofit program got, and are the buildings on liquefiable ground done? Every building on the program’s list, by the year its retrofit was finished, against the state’s mapped liquefaction zones.

A soft-story building has a weak ground floor, garages or shopfronts under flats, that can fold in an earthquake. In 2013 San Francisco required the owners of about 5,000 wood-frame buildings of three or more storeys and five or more units to strengthen them, in four tiers with deadlines from 2017 to 2020. On the program’s list as of 7 October 2026, 4,662 of 4,901 parcels (95.1%) are listed complete. In the mapped liquefaction zones, where shaking is worst, it is 657 of 698 (94.1%), and 37 are still listed non-compliant.

The list says what, not when or where

The city publishes the program’s list weekly: each building’s block and lot, tier and status, today. It does not say when each building was finished, so progress over the years cannot be read from it, and it does not say which buildings stand on ground that can liquefy. The dates are in another dataset, the city’s building permits: 9,403 permits name the soft story work. The ground is in a third, from the state: the California Geological Survey’s mapped liquefaction zones. Here the three meet on each parcel.

The map

Each parcel on the list, coloured by its state in the year on the slider, over the liquefaction zones in blue. Press Play to watch the city fill in. Hover over a parcel, or tap it on a phone, for its tier, status and year.

The zones lagged, by design

The ordinance put buildings in mapped liquefaction zones in Tier IV, the last deadline (15 September 2020), unless they belonged in Tier I. 405 of the 698 zone parcels are Tier IV. So at the end of 2018 the zones were 8.1 percentage points behind the rest of the city (41.5% against 49.6% with a completed permit). By 2026 they have all but caught up: 85.5% against 86.2%.

Against the deadlines

By its deadline, 62.6% of Tier II had a completed permit (15 September 2018), 62.6% of Tier III (2019) and 57.8% of Tier IV (2020). Most of the rest followed within two years. Today Tier IV, the zones’ tier, is 92.3% complete, with 76 parcels non-compliant.

How it was made in Plotlay

1. A map project on the USGS National Map topo base map (public domain), and two data layers.
2. Soft-story parcels: Take all. The city’s parcel file as a layer to pick from, with its licence: 4,899 parcels in one step, keyed by their own block and lot.
3. Link by key the program’s list, then one row per parcel and year from 2014 to 2026 as a time axis.
4. Colour by the state that year: retrofitted, not yet, complete with no known year, and in 2026 still not done or under review. Play steps the years.
5. Liquefaction zones: Take all from the state’s file, drawn over the parcels.
6. Charts and map pictures in the Analysis workspace: the lines above and the neighbourhood maps, each exported as PNG.
7. Export GeoJSON, TopoJSON for the Power BI Shape Map, CSV with WKT and the linked data.

More about Data layers · Make a data layer of your own

Power BI

Python

A narrated Jupyter notebook reads the tables and shapes, recomputes every number on this page, shows why the zones lagged, and maps the parcels over the zones.

Download the notebook (with its outputs) and the data. Both are also in the repository on GitHub.

Read it carefully

• Years come from permits. A parcel’s year is the earliest completed date of a completed soft story permit on it. 444 parcels the program lists as complete have no such permit in the open data; they count as complete in the status figures and never as done in the year-by-year figures, which is why those end at 86.1%, not 95.1%.
• The program’s status is the authority. A completed permit is not the city’s certificate of compliance; parcels are counted by their listed status.
• The zones are today’s. The California Geological Survey revised part of San Francisco’s map in 2021, and the program assigned tiers from the maps of its time, so some zone parcels are Tier II or III. A parcel counts as in a zone when a point inside it is.
• One row per parcel. 4,958 list rows are 4,901 parcels; a parcel listed under two addresses keeps its least finished status.

The other United States showcase

• Which buildings face Local Law 97 fines?: every benchmarked New York City building’s emissions against its limit.