# 2027 Construction Law Changes in California: What Los Angeles Homeowners Should Plan For *Published 2026-10-20 by 1 Smart Build* AB 956, SB 1117 and SB 908 all take effect January 1, 2027. Here is what changes for Los Angeles homeowners and how to plan ahead. January 1, 2027 is a big date for California homeowners. Several new laws take effect that day, and a few of them change what you can build in your own backyard. Here is a plain-English look at what is coming and how to plan around it. A Los Angeles residential build. Photo: 1 Smart Build. ## Key Takeaways - AB 956 requires cities to approve two detached new-construction ADUs on a qualifying single-family lot. - SB 1117 ends the 750 sq ft impact fee cliff for the first two ADUs on a lot. - SB 908 limits HOA restrictions on qualifying window replacements. - Local rules, utilities, setbacks and fire access still decide what is buildable on your lot. ## 1. Two detached ADUs on one lot (AB 956) Today the state fast-track covers one detached ADU. Starting January 1, 2027, cities must approve two detached, newly built ADUs on a lot with a single-family home when the plans meet state standards. Cities may still cap each unit at 800 sq ft of living space and apply height limits, and side and rear setbacks cannot exceed 4 feet. If you build two detached ADUs this way, the city does not have to approve a Junior ADU on the same lot. The law also widens protections against HOA and deed restrictions on ADUs. Full breakdown: [AB 956 explained](/blog/california-ab-956-two-detached-adus-2027). Backyard space is the starting point for a second detached unit. ## 2. The 750 sq ft fee cliff goes away (SB 1117) Right now an ADU over 750 sq ft can be charged impact fees on its full size, which is why so many plans stop at 749 sq ft. From January 1, 2027, for the first and second ADU on a lot, fees can only be based on the livable space above 750 sq ft. School fees, utility connection charges and plan check and permit fees are not removed, and each agency sets its own rates. Details: [SB 1117 and the fee cliff](/blog/california-sb-1117-adu-impact-fees-750-sq-ft-2027). ## 3. Window replacement and HOAs (SB 908) SB 908 will void HOA rules that effectively prohibit qualifying window replacement projects, with limits on cost and energy-efficiency impacts. The replacement must match the existing size and location and meet the California Energy Code. Condo and common-area windows have extra conditions, so read your governing documents first. Energy-efficient windows and finishes are a common upgrade. ## What this means for different homeowners - **Long, narrow lots:** the 4-foot setback rule may open room for two small units. Survey first. - **Families building for parents or kids:** two small ADUs can serve two households. See our [multigenerational ADU guide](/blog/los-angeles-multigenerational-aging-in-place-adu-trends-2026). - **Investors:** lower fee math may improve returns on larger ADUs. Run numbers with our [ADU calculator](/adu-calculator). - **HOA homeowners:** more protection, but read your CC&Rs and ask before you commit. Framing stage of a residential project. ## What does not change Plans, structural and Title 24 energy compliance, utilities, fire access, hillside rules and inspections all still apply. Many lots need an electrical or water service upgrade, so read [electrical panel upgrades](/blog/ladbs-ladwp-electrical-panel-upgrade-guide-los-angeles) and [water service for ADUs](/blog/water-service-line-upgrade-adu-addition-los-angeles) early. ## A simple 2027 game plan - Order a lot review and survey now. - Decide on one ADU, two ADUs, or an addition. - Check utility capacity and your city's fee schedule. - Start design so plans are ready when the new rules take effect. - Get a fixed-price proposal covering design, permits and construction. The goal: a finished home that fits your lot and budget. Costs and timelines vary by lot and city. [Request a free consultation](/contact) or see our [ADU and garage conversion services](/services/adu-garage-conversion). This article is general information, not legal advice. ## Frequently Asked Questions ### What California construction laws take effect January 1, 2027? Several residential bills take effect that day, including AB 956 (two detached ADUs on a single-family lot), SB 1117 (ADU impact fees on space above 750 sq ft) and SB 908 (limits on HOA restrictions for window replacement). ### Will I be able to build two detached ADUs in Los Angeles in 2027? AB 956 requires cities to approve two detached, new-construction ADUs on a lot with a single-family home if the project meets state standards. Your lot, utilities, setbacks and fire access still decide what actually fits. ### Should I wait until 2027 to start my ADU? It depends on your plan. If you want a larger ADU or a second detached unit, the 2027 rules may help. Design, surveys and plan check take months, so many owners start preparation now. We review your lot and give an honest recommendation. ### Do the 2027 changes lower my permit fees? Not all of them. SB 1117 changes how impact fees are calculated for ADUs over 750 sq ft, but it does not remove school fees, utility connection charges or plan check and permit fees. ### Can my HOA stop a window replacement in 2027? SB 908 limits HOA power to block qualifying window replacement projects, with conditions. Check your governing documents and city rules before ordering windows. ### Is this legal advice? No. This is general information from a licensed contractor. Confirm details with your city, county or an attorney before you build. ## Company facts - Business: 1 Smart Build, design-build general contractor - Phone: 1 (866) 419-8840 - Email: info@1smart.build - Office: 21243 Ventura Blvd #133, Woodland Hills, CA 91364 - License: California CSLB #1076428 (Class B, General Building Contractor) - Insurance & bond: $1,000,000 liability policy, $15,000 contractor bond - Reviews: 4.9 stars on Google (169 reviews) - Ownership: Veteran-owned and women-owned - Service area: Los Angeles County and the San Fernando Valley Canonical HTML version: https://1smart.build/blog/california-2027-construction-law-changes-los-angeles-homeowners Site index for agents: https://1smart.build/llms.txt