I recently heard from a neighbor who is concerned about housing density impacting our semi-rural Mt. Helix neighborhood. We have all heard bits and pieces of the state legislation (SB-9 and SB-10) that were passed to encourage housing development. California Planning and Zoning Law requires a city or county to adopt a general plan for land use development which includes also the housing element. The main difference between SB-9 and SB-10 is the zoning type where they are applicable. SB-9 applies ONLY to single-family zoned lots like the area where I live. As opposed to SB-10 which applies to parcels zoned for multi-family buildings if the parcel is located in a transit-rich area or an urban infill site.
Here is State of California's Executive Summary of SB 9 Senate Bill:
(SB) 9 (Chapter 162, Statutes of 2021) requires ministerial approval of a housing development with no more than two primary units in a single-family zone, the subdivision of a parcel in a single-family zone into two parcels, or both. SB 9 facilitates the creation of up to four housing units in the lot area typically used for one single-family home. SB 9 contains eligibility criteria addressing environmental site constraints (e.g., wetlands, wildfire risk, etc.), anti-displacement measures for renters and low-income households, and the protection of historic structures and districts. Key provisions of the law require a local agency to modify or eliminate objective development standards on a project-by-project basis if they would prevent an otherwise eligible lot from being split or prevent the construction of up to two units at least 800 square feet in size. For the purposes of this document, the terms “unit,” “housing unit,” “residential unit,” and “housing development” mean primary unit(s) unless specifically identified as an accessory dwelling unit (ADU) or junior ADU or otherwise defined.
What this means in simpler terms is in a single family neighborhood is you can split your lot (within guidelines related to space and who will live in the primary unit) and build a second primary unit. At each primary unit you can add an ADU.
SB-10 is a concern in areas zoned for multi-units. That does not pertain to Mt. Helix but could pertain to some lovely more urban areas like Talmadge and North Park. At this point the City of San Diego rejected SB-10 at its August Planning Commission Meeting. That could change in the future though so pay attention to this issue. For more information read this SD Magazine article.