How Simi Valley Handles Accessory Structures: A Practical Guide

Simi Valley maintains 136 local ordinances across all categories, and 5 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Simi Valley falls on the strict-to-permissive spectrum compared to other cities.

ADU Rental Restrictions

Simi Valley bars short-term rental of accessory dwelling units. SVMC Section 9-44.160(A)(10) requires that renting an ADU, a Junior ADU, or the primary home (when the owner lives in the ADU or JADU) be for periods of 30 days or more, closing off nightly or weekly rentals through platforms like Airbnb for any of these units.

Key details: Minimum rental term: 30 days or more for ADU/JADU. Governing section: SVMC Section 9-44.160(A)(10). Also covered: Primary home, if owner lives in the ADU/JADU. Approval type: Ministerial Zoning Clearance, 60-day review. Applies to: Every ADU and JADU citywide.

An ADU or JADU owner who lists the unit for a stay under 30 days is violating the General Provisions attached to the ADU's Zoning Clearance approval. Code enforcement can act on a complaint, and because the 30-day minimum is a condition of the ministerial approval itself, the City can treat a confirmed short-term rental as an unpermitted use of the accessory unit, exposing the property to the same enforcement remedies used for other zoning violations.

ADU Owner Occupancy

A Junior Accessory Dwelling Unit in Simi Valley comes with a recorded owner-occupancy deed restriction. SVMC Section 9-44.160(D)(2) requires the property owner to record a deed restriction promising to occupy either the JADU or the primary home, and a new owner who breaks that promise must remove the JADU and vacate any separate rental within 90 days.

Key details: Requirement: Recorded deed restriction before Zoning Clearance issues. Who must occupy: Owner, in the JADU or the primary home. If occupancy lapses: JADU removed, rental vacated within 90 days. Governing section: SVMC Section 9-44.160(D)(2). Applies to: Junior ADUs only, not standard ADUs.

A JADU found without a currently valid owner-occupancy deed restriction, or where neither the JADU nor the primary dwelling is occupied by the recorded owner, is out of compliance with Section 9-44.160(D)(2). Once the City confirms the lapse, typically after a change in title, the property owner has 90 days to either restore owner occupancy, vacate any separate tenancy, or remove the JADU altogether.

This is not one of those rules that cities tend to ignore. Simi Valley actively enforces its adu owner occupancy requirements.

Garage Conversions

Simi Valley ministerially allows an attached or detached garage to be converted to an ADU under SVMC 9-44.160(E)(1): no additional setbacks are required when keeping the existing footprint, and lost garage parking is generally waived under state law.

Key details: Code section: SVMC 9-44.160(E)(1)–(2), A(11), A(17). Setback relief: Same footprint = no new setbacks required. Ingress/egress bonus: Up to 150 sq ft expansion allowed. Replacement parking: Not required when a garage is converted to an ADU. Partial garage conversion: Remaining space must keep parking if ≥ 12 × 20 ft.

Occupying a converted garage as an ADU without a Zoning Clearance, building permit, and California Building Code compliance can trigger code enforcement and require removal of habitable improvements; converting a garage that was not legally permitted in the first place forfeits the relaxed setback and parking allowances.

ADU Rules

Simi Valley permits one ADU plus one JADU per single-family lot ministerially under SVMC 9-44.160, conforming the city to state law (Gov't Code 65852.2 and 65852.22) with 4-ft side/rear setbacks, 18-ft height, and up to 1,200 sq ft detached.

Key details: Code section: SVMC 9-44.160 (Ord. 1316, Nov. 2, 2020; amended 2023). Review: Ministerial Zoning Clearance, 60-day deadline. Setbacks: Front 20 ft; side 4 ft; rear 4 ft. Height: 18 ft, single story. Detached ADU max size: 1,000 sq ft (parcels ≤8,000 sq ft); 1,200 sq ft (parcels >8,000 sq ft).

Building or occupying an ADU without a Zoning Clearance and building permit can trigger code enforcement, stop-work orders, and a requirement to remove or legalize the structure; a JADU rented out without the recorded owner-occupancy deed restriction must be vacated within 90 days of a new owner taking title.

Shed & Carport Rules

Detached freestanding sheds and similar nonresidential accessory structures must sit at least 20 ft from the front, 3 ft from side and rear lot lines per SVMC 9-30.080 Table 3-2, may cover no more than 40% of any yard, and require a building permit if the floor area exceeds 120 square feet.

Key details: Code section: SVMC 9-30.080 Table 3-2 (Ord. 1316). Shed setbacks: Front 20 ft; side 3 ft; rear 3 ft. Maximum height: 18 ft (Figure 3-7). Yard coverage: ≤ 40% of any yard, cumulative. Permit threshold: Building permit required if > 120 sq ft.

Constructing a shed over 120 sq ft without a building permit, or placing any shed inside the required 3-ft setback, can trigger code enforcement, fines, and an order to relocate or remove the structure under SVMC Title 1 enforcement provisions.

The Bottom Line

Simi Valley's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Simi Valley is broadly strict or permissive.

This guide is based on Simi Valley's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.