Which CEQA Exemption Applies to Your Infill Project?

If your project sits on an already-developed urban site, consistent with local zoning, and doesn't touch sensitive habitat, it likely qualifies for a CEQA exemption rather than a full environmental review. The Class 32 infill exemption (14 CCR §15332) covers general-plan-consistent projects up to 5 acres with no traffic, noise, or utility problems. Smaller single projects often qualify under Class 1 or Class 3 instead, and ministerial approvals like ADUs and SB 9 lot splits are exempt by statute.

For most Southern California owners doing a duplex, a small apartment building, an ADU, or a modest commercial infill project, the CEQA question isn't "how do I survive an EIR" — it's "which exemption gets me out of CEQA review altogether." Picking the wrong one, or missing a disqualifying detail, is one of the more common ways a straightforward infill project loses weeks to an avoidable CEQA challenge.

What is the Class 32 infill exemption, and does your project qualify?

The Class 32 infill exemption (14 CCR §15332) covers qualifying infill development on a site no larger than 5 acres, and it's the exemption most small-to-mid infill projects in built-out LA, Orange, and San Diego County cities end up relying on. To qualify, a project must meet all five criteria in the regulation:

1. The project is consistent with the applicable general plan designation and policies, and with applicable zoning.
2. The project site is within city limits, no larger than 5 acres, and substantially surrounded by urban uses.
3. The site has no value as habitat for endangered, rare, or threatened species.
4. Approval would not result in significant effects on traffic, noise, air quality, or water quality.
5. The site can be adequately served by all required utilities and public services.

The 5-acre cap is measured against the project site — the area actually being developed or disturbed — which is not always the same thing as the assessor's parcel. A 2021 California appellate ruling, Protect Tustin Ranch v. City of Tustin, upheld a Class 32 exemption for a project on a 2.38-acre portion of a nearly 12-acre shopping center because substantial evidence in the record defined the project site as under 5 acres. That cuts in owners' favor on larger parcels, but only if the project-site definition is documented carefully — a sloppy record is what invites the challenge.

What other categorical exemptions cover small residential and commercial projects?

Below the Class 32 threshold, several narrower categorical exemptions in the CEQA Guidelines (14 CCR §15300 et seq.) cover projects that never needed the infill exemption's five-part test in the first place.

Class 1 — Existing Facilities (§15301) covers operation, repair, maintenance, or minor alteration of an existing structure with negligible or no expansion of use. This is the exemption for interior remodels, like-for-like commercial tenant improvements, and repairs that don't add square footage or intensify use.

Class 3 — New Construction of Small Structures (§15303) sets unit and size caps for ground-up construction:

Class 15 — Minor Land Divisions (§15315) covers splitting a parcel in an urbanized area, zoned residential, commercial, or industrial, into 4 or fewer parcels, when the division is consistent with the general plan and zoning and requires no variance.

None of these smaller classes require the general-plan-consistency-plus-five-acre-plus-habitat test that Class 32 does — they're narrower, but faster to confirm you qualify for.

Are ADUs and SB 9 lot splits exempt from CEQA?

Yes, but through a different legal mechanism than a categorical exemption — they're exempt because the approval itself is ministerial, and CEQA only applies to discretionary government decisions. An ADU application that meets the objective standards in Government Code §66314 et seq. (state ADU law, recodified in 2024 from the former §65852.2) must be approved without a public hearing or case-by-case judgment call, which takes it outside CEQA's scope entirely. The same logic applies to SB 9 duplexes and urban lot splits under Government Code §65852.21 and §66411.7 — if the project meets the statute's objective criteria, the city has no discretion to weigh environmental impacts project-by-project, so no CEQA document or exemption filing is needed.

Separately, Public Resources Code §21159.24 provides a statutory exemption (modeled on Class 32) for urbanized-area residential infill sites up to 4 acres and 100 units — subject to a longer list of mandatory conditions than Class 32, including location within a half-mile of a major transit stop, an affordable-housing component, and a community-level environmental review certified within the prior five years. On density: a project at 20+ units per acre conclusively qualifies on that criterion, while one at 10+ units per acre qualifies presumptively if it exceeds the average density of residential properties within 1,500 feet.

How do you file a Notice of Exemption, and why does timing matter?

A Notice of Exemption (NOE) is a short public filing that starts the clock on how long anyone has to legally challenge your project's reliance on a CEQA exemption. Filing early protects the project; skipping it leaves the door open far longer.

Under Public Resources Code §21152, the lead agency (or the applicant, for certain private projects) files the NOE with the county clerk once the exemption determination is made and the project is approved. Filing triggers a 35-day statute of limitations for anyone to challenge the exemption in court, per Public Resources Code §21167(d). If no NOE is filed, that window stretches to 180 days after project approval — five times longer for a challenge to surface. County clerks charge a documentary handling or posting fee for the filing — Fish & Game Code §711.4(e) authorizes up to $50, and amounts vary by county (Los Angeles County, for example, lists a $25 NOE posting fee effective January 1, 2026). Unlike Negative Declarations and EIRs, an NOE carries no CDFW environmental filing fee; confirm the current amount with the specific county clerk before filing.

When can a city deny or lose a categorical exemption even if your project fits the criteria?

Meeting a categorical exemption's listed criteria isn't automatically the end of the analysis — the "unusual circumstances" exception in 14 CCR §15300.2(c) can still apply. It says no categorical exemption applies if there's a reasonable possibility the project will have a significant environmental effect due to unusual circumstances.

The California Supreme Court's 2015 decision in Berkeley Hillside Preservation v. City of Berkeley (60 Cal.4th 1086) set the two-part test courts now use: first, whether the circumstances are genuinely unusual for that class of project (a factual question); second, if they are unusual, whether a fair argument exists that a significant effect is reasonably possible. In practice, the circumstances that most often defeat an otherwise-qualifying exemption are:

• Steep slopes or geologic hazards not typical for that project type
• Habitat value the site assessment initially missed
• Historic or potentially historic structures on site — under §15300.2(f), any substantial adverse change to a historical resource takes the exemption off the table regardless of size or acreage
• Piecemealing — splitting one larger project into smaller phases specifically to stay under an exemption's size cap, which agencies and courts both watch for as a sign the cumulative impact is being understated

Is the CEQA infill exemption changing in 2026?

Yes — the state significantly expanded infill CEQA exemptions in mid-2025, and the changes are still working through implementation as of this writing. AB 130 and SB 131, signed June 30, 2025, created a new statutory exemption (Public Resources Code §21080.66) for infill housing on sites up to 20 acres — four times the Class 32 cap — with no affordable-housing set-aside and no unit cap, in exchange for meeting minimum density (at least half the applicable "Mullin" density) and, for buildings over 85 feet, labor conditions. SB 131 separately narrows CEQA review (Public Resources Code §21080.1) for housing projects that miss a statutory or listed categorical exemption by a single condition, limiting review to the effects of that one condition rather than reopening the whole project. If your site is between 5 and 20 acres, it's worth checking whether this newer exemption now applies where Class 32 previously wouldn't have.

Which exemption path fits your project?

The categorical exemption rows above (Classes 1, 3, 15, and 32) also assume the project doesn't trigger the §15300.2 exceptions — habitat, historic resources, scenic corridors, or hazardous sites. (Statutory and ministerial exemptions aren't subject to §15300.2, though §21080.66 carries its own built-in site exclusions.) Confirming which exemption fits, and documenting it correctly with an NOE, is the kind of detail that's cheap to get right up front and expensive to fix after a challenge.