Cities | Simi Valley

Simi Valley Multiplex Rules 2026: Zoning, ADUs, SB 9, Apartments, Hillsides and Fees

Simi Valley is a city in Ventura County that, in its own code's words, "is situated among a series of major and minor hills." Its zoning, subdivision and hillside rules sit in Title 9 of the Simi Valley Municipal Code, the Development Code, which the City publishes on Municode. The code permits apartments in three districts, writes SB 9 into its own section, limits homes on hillsides by slope, and releases building permits for new homes through a yearly allocation under Measure N. This page sums up the routes to two, three, four or more homes on a Simi Valley lot, what each allows, and where the code and state law differ. The seven guide pages below cover each topic in depth.

Simi Valley Guide Pages

Start With State Law

Four state laws set the floor Simi Valley must allow. SB 9 (2021) allows two main homes on a lot in a single-family zone, a split into two lots, or both, approved by staff with no hearing. ADU law sets the accessory dwelling units (ADUs), which are second homes on a lot, and junior ADUs a city must allow; a junior ADU is a unit of 500 square feet or less inside the house. SB 684 and SB 1123 allow maps of up to 10 lots with 10 homes. The state density bonus gives extra homes to projects of five or more units that include affordable homes.

Simi Valley carries SB 9 and ADU law into its own code: the Two-Unit Residential Development and Urban Lot Split in Section 9-24.080, and ADUs in Section 9-44.160. It has no section on small-lot maps, so Government Code 66499.41 applies on its own terms. The SB 9 statutes apply to every city "whether general law or chartered," so they apply in Simi Valley whatever its form of government. Its density bonus chapter dates from 2010 and stops at 35 percent, below the 50 percent the statute now allows.

SB 79 allows taller and denser projects near qualifying rail and bus stops. HCD's SB 79 advisory says its upzoning provisions took effect on July 1, 2026 in Alameda, Los Angeles, Sacramento, San Francisco, San Mateo, Santa Clara and San Diego Counties, and that "the geographic scope of SB 79 is dynamic and will modify over time." Ventura County is not on that list, so SB 79 does not change zoning in Simi Valley today.

Simi Valley in Numbers

The US Census Bureau's Vintage 2025 city file estimates 124,861 people in the City of Simi Valley on July 1, 2025, down from a 2020 estimates base of 126,375. In that file Simi Valley is the 48th largest city in California, after Clovis (129,347) and ahead of Vallejo (123,287). Ventura County has 830,851 people in the same file.

Most housing decisions are made by the Director of the Environmental Services Department or the Planning Commission. The Director decides ADU and SB 9 Zoning Clearances, Planned Development Permits for two to four homes, Tentative Parcel Maps and Urban Lot Splits. The Commission decides Planned Development Permits for five or more homes, Tentative Tract Maps, Cluster Development Permits and Conditional Use Permits. The City Council decides senior and affordable projects, Vesting Tentative Maps and rezonings, and hears appeals. Most appeals must be filed within 14 days. The permits and fees page has the deadlines.

The Routes to More Homes Compared

Sources: Simi Valley Municipal Code Table 2-2, Table 2-3, Sec. 9-24.080, Sec. 9-44.160, Sec. 9-52.040 and Sec. 9-52.050; Gov. Code 66499.41.

Zones That Allow Homes

Chapter 9-24 sets nine residential and open space districts. OS, RE, RVL, RL and RM are house districts, from one primary home per 40 acres in OS to 3.6 to 5.0 homes per acre in RM, each with one dwelling per lot. RMod allows houses or multi-family buildings at 5.1 to 10.0 homes per acre. RH allows townhouses and apartments at 10.1 to 20, and RVH compact apartments near shopping centers at 20.1 to 35.0; neither permits a stand-alone house. MH is for mobile home parks. Overlays add rules on top, including a Mixed-Use Overlay that allows homes over shops at 20.1 to 35 homes per acre. See the zoning districts page.

House Lots: ADUs and SB 9

Section 9-44.160 allows one ADU and one junior ADU with a house. A detached ADU may be 1,000 square feet on a parcel up to 8,000 square feet and 1,200 square feet on a larger parcel, one story and 18 feet tall, with four-foot side and rear setbacks; an attached ADU may be half the house or 800 square feet, up to 1,000. One parking space is required unless one of six exceptions applies. HCD's October 29, 2025 letter found that Ordinance No. 1349, the source of this text, "fails to comply with State ADU Laws" on 19 points, including the limit of two detached ADUs on apartment lots, where state law allows up to eight. See the ADUs and SB 9 page.

Section 9-24.080 allows "a maximum of two primary residential units on one parcel," each with one ADU, up to four homes, sized by the parcel from 800 square feet up to 2,000. An Urban Lot Split creates two lots of at least 1,200 square feet and 40 percent of the original. The owner must live on site for three years, the home may not have had a tenant in the last three years, and a two-story SB 9 home is asked for 10 foot side and 20 foot rear setbacks where state law allows a city to require four feet. The lot size and subdivisions page covers lot sizes, maps and small-lot subdivisions.

Three or More Homes

A project of two or more homes needs a Planned Development Permit, decided by the Director for two to four homes and by the Planning Commission for five or more. A project of five or more homes must also include at least 11 optional standards from a City menu, such as half the units with three bedrooms or an enclosed garage for each unit. Then it waits for building permit allocation grants: 292 enter the system each year, a project may take up to half of those available in a year, and grants last four years. RH and RVH buildings may be three stories or 40 feet. See the three or more homes page.

Parking, Setbacks and Height

A house needs two spaces in an enclosed garage, each at least 10 by 20 feet inside. Apartments need 1 space for a studio up to 2.5 for three or more bedrooms, plus half a guest space per unit. In the house districts a home sits 20 feet from the front and rear lot lines and may be two stories and 30 feet tall. Projects of four or fewer homes may use five-foot side yards for one story if the Commission agrees. See the parking, setbacks and height page.

Hills, Fire and Flood

Land outside the valley floor line follows the Hillside Performance Standards: at most 7 homes per acre on slopes under 10 percent, one per four acres on 15 to 20 percent, and one per 40 acres on 20 percent or more; no structure within 150 feet of a visually prominent ridgeline; and buildings no taller than two stories or 35 feet. SB 9 homes in Very High Fire Hazard Zones must meet fire construction standards, and the City adopted the 2025 Wildland-Urban Interface Code in December 2025. Title 7 bans new homes in mapped flood zones. See the hillside, fire and flood rules page.

Fees

Simi Valley sets planning and building fees in its Schedule of Service Charges, adopted by Council resolution, and this guide could not read it. The code itself prints a fee on every new home of $150 for a unit with up to one bedroom plus $75 per added bedroom, capped at $300, paid with the building permit and adjusted each year by inflation from a 1978 base. Subdivisions dedicate five acres of park land per 1,000 future residents or pay the value instead. See the permits and fees page.

Where the Code and State Law Differ

The guide pages flag each gap where it arises. The main ones:

• HCD's October 2025 letter lists 19 ways Section 9-44.160 falls short of state ADU law, from old statute numbers to apartment-lot ADU counts and parking exemptions. State law controls.
• Table 3-2 in Section 9-24.080 asks 10 foot side and 20 foot rear setbacks for two-story SB 9 homes; Government Code 65852.21 and 66411.7 allow a city to require up to four feet. The statutes control.
• Section 9-24.080 sets an owner occupancy rule for lot splits that runs from map recording or first occupancy; Government Code 66411.7 asks only an affidavit of intent from approval and bars added owner occupancy rules. The statute controls.
• Chapter 9-31 caps the density bonus at 35 percent; Government Code 65915 reaches 50 percent. The statute controls.
• Table 3-4 prints parking minimums everywhere; Government Code 65863.2 bars them within one-half mile of public transit unless the City makes findings. The statute controls.
• Section 9-24.030 requires a Planned Development Permit for "all construction of new residential units," and Section 9-52.050 for projects of "two or more dwelling units."
• Table 3-3 prints the 10 to 15 percent slope rate as "1 unit per 2 acre (2 units per acre)," two figures that do not match.
• Section 9-24.080 lets SB 9 homes into the 100 year flood zone with mitigation; Section 7-5.601 bans all new residential construction in mapped flood zones.

Limits of This Guide

The City's website, simivalley.org, answered "Access Denied" to a request made for this guide, so no City web page, handout, fee schedule, zoning map, specific plan or Council record hosted there was read, and Municode's ordinance bank lists no Simi Valley ordinances. The code comes from Municode Supplement 52, current through March 9, 2026; any ordinance adopted after that date, including any response to HCD's ADU findings, is not reflected here. The Zoning Map, the Development Map of the Valley Floor, the General Plan and the Housing Element were not read. Confirm the rules for your lot with the Planning Division before you budget or design.

Where to Go Next

Related on VanPlex: the SB 684 and SB 1123 page, the California rent and tenant rules page and the duplex to fourplex guide.

Frequently Asked Questions

Official sources (checked October 2026)