SB 330 'affected cities': where the Housing Crisis Act bites hardest

The Housing Crisis Act of 2019 (SB 330, extended and expanded since) froze the zoning playing field: Government Code § 66300 bans downzoning below the January 1, 2018 baseline, bans housing moratoria, freezes subjective design standards adopted after 2020, and the Act caps duplicative hearings. This page is a curated snapshot as of July 2026 of the coverage question — which of those limits run everywhere, and which turn on "affected" status.

The Act reaches essentially everywhere housing gets built: several provisions bind every city and county outright, and the provisions keyed to "affected" status cover nearly all urban California because HCD's determination sweeps broadly. The authoritative roster is HCD's affected-cities determination (April 2023), and the state's official reading of how the pieces fit is the HCD Housing Crisis Act advisory.

The statute, not the city, answers the question: an "affected city" is one HCD determined to have territory within an urbanized area or urban cluster under census-based criteria set out in § 66300, and affected counties are keyed to their urbanized unincorporated territory. HCD ran that determination and published the resulting list in April 2023 — it runs to hundreds of jurisdictions, which is why this page links it rather than reproducing it. A short illustrative sample of well-known affected cities:

Keep the table general and the statute close: the split lives in the text of § 66300 itself, which has been amended repeatedly — SB 8 (2021) extended the Act into 2030 and expanded its reach, and later cleanup bills kept adjusting the demolition and replacement rules. In practice the "affected-only" column functions close to statewide, because the affected list captures nearly every jurisdiction where projects actually pencil. The rows keyed to affected status are the Act's sharpest teeth — which is why the coverage check comes first.

Three steps, five minutes: (1) find the city or county on HCD's April 2023 determination; (2) read the current § 66300 text for the specific provision you care about — the section has moved since 2019 and summaries age badly; (3) for a downzoning claim, reconstruct the zoning in force on January 1, 2018, because that snapshot is the baseline the ban protects. What turns on affected status in a real underwrite: whether the city can impose a moratorium mid-entitlement, whether a post-2020 "guideline" that isn't objective can bind your design, and whether the protected-unit replacement math attaches to a demolition.

• Verification watch-outs:
• The list is a point-in-time determination — annexations and census-geography changes can move edge cases, so verify borderline rural sites rather than assuming either way.
• Affected-only does not mean optional elsewhere: the statewide tools (hearing cap, preliminary-application vesting) bind non-affected jurisdictions too.
• Sunset math: the Act currently runs into 2030 and has been extended and amended more than once — pin the current text before a litigation posture hardens.
• The § 66300 shields protect existing zoned capacity; they grant no density. Pair them with the density-bonus and streamlining statutes for offense.