What ADU laws take effect in California on January 1, 2027?

Three that matter to ADU builders. AB 956 (Chapter 791) makes two detached ADUs per single-family lot a ministerial approval. SB 1117 (Chapter 809) re-bases local impact fees for up to two ADUs on only the square footage above 750. SB 1117 does not touch school developer fees or utility connection charges. SB 1196 also takes effect that day, but it is a utility-energization law, not a fee law — its binding deadlines arrive through a CPUC proceeding due by September 30, 2027.

How much do impact fees drop under SB 1117?

For covered city and county impact fees, the assessable basis for an 800 sq ft ADU falls from 800 sq ft to the 50 sq ft above the 750 threshold — in proportional-fee cities like Folsom, a worked example falls from about $10,477 to roughly $40. Fees that are not covered impact fees do not drop at all: school developer fees (up to $8,208 in Folsom) and water/sewer connection or capacity charges are expressly outside the statute.

Does SB 1196 change any ADU fees?

No. SB 1196 amends the Public Utilities Code (§931, new §934.5), not the Government Code, and its final text never mentions accessory dwelling units. It orders the CPUC to set processing deadlines, defect-notice rules, and penalties for 'small energization projects' — new-meter-only service requests, a category most ADU hookups fall into — by September 30, 2027. One provision (§934.5(d)(5)) requires utilities to provide fee and upgrade-cost estimates up front: a transparency rule, not a fee change.

Should I wait until 2027 to build my ADU?

On fees alone, waiting saves real money only where covered impact fees are large — five figures in the heaviest proportional cities, near zero where impact fees are already $0 under 750 sq ft or where the bill is dominated by school fees and utility charges, which do not change. AB 956's second-ADU right also starts January 1, 2027. Against that, construction pricing and your own timeline usually swamp a fee delta; the laws change the government lines of the budget, not the construction lines.

California ADU Laws Changing January 1, 2027: Two Rewrite Your Fees, One Rewrites Your Power Hookup

Published: 28 Oct 2026 · Last verified: 21 Oct 2026 · Next review: Jan 2027 Cost figures are re-checked against permit records quarterly. Changes are logged in Corrections.

Three California laws land on ADU projects on January 1, 2027. Two of them rewrite your government fee bill. The third is routinely described as an ADU fee law and is not one — it is about how long the power company may take to energize your unit, and its real deadlines arrive nine months later. This hub is the short, sourced version of all three, with links to the deep dives and to your city’s page.

AB 956 — two detached ADUs per lot, ministerially

What it does. From January 1, 2027, a local agency must ministerially approve two detached ADUs on a lot with a proposed or existing single-family dwelling (Gov. Code §66323(a)(2), as amended by Chapter 791). Each can be up to 800 sq ft with 4-foot side and rear setbacks and a 16-foot height limit (18 feet near transit). No JADU is required alongside them, and HOA bans on ADUs are further restricted.

What it does to your bill. Indirectly, everything: a second unit means a second run through the fee table — under the post-2027 fee rules below.

Deep dive: Two Detached ADUs Per Single-Family Lot From Jan 1, 2027

SB 1117 — impact fees shrink to the 50 sq ft margin

What it does. SB 1117 (Chapter 809) adds Gov. Code §66311.5: for up to two ADUs, a local agency may assess covered impact fees only on the area in excess of 750 square feet, proportionate under the existing §66324 framework. An 800 sq ft ADU is billed as if it were 50.

What it does to your bill. Covered city/county impact fees collapse — in a worked proportional example, fees fall from ~$10,477 to ~$40. Every jurisdiction page in our fee index now carries a “What changes on January 1, 2027” block with the same summary.

What it does not touch. School developer fees are not covered impact fees — Folsom’s $8,208 Level II school fee is identical on January 2. Connection and capacity charges for water and sewer are expressly excluded (§66311.5(c)(2)). Charter cities are covered; a third ADU on the lot is billed the old way.

Deep dive: SB 1117 Kills the 750 Sq Ft Cliff

SB 1196 — the utility law that is not a fee law

What it actually is. SB 1196 (McNerney) amends Public Utilities Code §931 and adds §934.5. The enrolled text contains no ADU provision at all — an earlier 2026 version was ADU-specific, but June 29 Assembly amendments generalized it to “small energization projects”: service requests that need no distribution or service-line extension or upgrade, including projects that need only a new meter. Most ADU hookups are exactly that.

What it does. It orders the CPUC to establish, by September 30, 2027, processing deadlines for energization applications, rules for notifying applicants of defects, and penalties for utility non-compliance. Energization applications may be filed alongside the building permit application, and a utility may not cancel one without the applicant’s consent. Section 934.5(d)(5) requires utilities to give applicants their applicable fees and any upgrade-cost estimates up front — a transparency requirement that changes what you are told, not what you are charged.

Why it is on this page. Because “2027 ADU laws” roundups keep listing it next to the fee bills, and the difference matters for budgeting: the law takes effect January 1, 2027, but the deadlines and penalties that could actually shorten a hookup wait do not exist until the CPUC proceeding concludes, due September 30, 2027. Plan 2027 projects on the old energization timelines; treat anything faster as a bonus.

Your city, line by line

Every jurisdiction page in the fee index shows the current verified table and the January 1, 2027 block side by side. For whole-project budgets, start from the city cost breakdowns or run your own square footage through the fee calculator.

Sources

AB 956, Chapter 791 (2026) — enrolled text, California Legislative Information (Gov. Code §66323).
SB 1117, Chapter 809 (2026) — enrolled text, California Legislative Information (Gov. Code §66311.5).
SB 1196 (McNerney, 2026) — enrolled text, California Legislative Information (Public Utilities Code §§931, 934.5). Chapter number pending confirmation in our verification file; section citations are from the enrolled text.

Disclaimer

This post summarizes three statutes for general information; it is not legal advice, and local implementation ordinances may add parcel-level conditions. Fee figures cited from other posts carry their own verification dates. Confirm your project’s treatment with your city or county planning department.