Cities | Vallejo

Vallejo Multiplex Rules 2026: Zoning, ADUs, SB 9, Apartments, Historic Districts and Fees

Vallejo is a charter city in Solano County. Its zoning rules sit in Title 16 of the Vallejo Municipal Code, the Zoning Code, which the City adopted in 2021 and publishes on Municode. The code permits duplexes on low-density lots, triplexes and apartments in two residential districts and three mixed-use districts, and gives a 25 percent density bonus near transit. In 2026 the City replaced its ADU rules. This page sums up the routes to two, three, four or more homes on a Vallejo lot, what each allows, and where the code and state law differ. The seven guide pages below cover each topic in depth.

Vallejo Guide Pages

Start With State Law

Four state laws set the floor Vallejo 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 a 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.

Vallejo writes ADU law into Chapter 16.303, replaced in 2026, and the density bonus into Chapter 16.214. It has no SB 9 section, but its fee schedule lists SB 9 lot split and two-unit fees, so the City takes the applications under the statutes. Vallejo is a charter city, a city that runs under its own charter; its City Charter was ratified by voters on June 2, 1970. The SB 9 statutes define a local agency as a city "whether general law or chartered." Vallejo has no section on small-lot maps, so Government Code 66499.41 applies on its own terms.

SB 79 allows taller and denser projects near qualifying rail and bus stops. HCD's SB 79 advisory lists seven counties where its upzoning took effect on July 1, 2026: Alameda, Los Angeles, Sacramento, San Francisco, San Mateo, Santa Clara and San Diego. Solano County is not among them, so SB 79 does not change zoning in Vallejo today. Vallejo's own transit-oriented development chapter already raises density by up to 25 percent near the ferry terminal and the transit centers.

Vallejo in Numbers

The US Census Bureau's Vintage 2025 city file estimates 123,287 people in the City of Vallejo on July 1, 2025, down from a 2020 estimates base of 126,084. In that file Vallejo is the 49th largest city in California, after Simi Valley (124,861) and ahead of Concord (123,261). Solano County has 455,376 people in the same file.

Most housing decisions are made by the Planning and Development Services Director, the Planning Commission, the Design Review Board or the Architectural Heritage and Landmarks Commission. The Director decides projects of 2 to 10 homes and minor use permits without a hearing, and the development services director decides parcel maps; the Planning Commission decides projects of 50 or more homes, tentative maps, major use permits and variances. Appeals must be filed within ten calendar days. The City's staff report on the new ADU chapter says the City issued planning approvals for 19 ADUs in calendar year 2025. The permits and fees page has the deadlines.

The Routes to More Homes Compared

Sources: Vallejo Municipal Code Table 16.301-A, Table 16.202-B, Table 16.203-A and Sec. 16.202.05; Ordinance No. 1890; Gov. Code 65852.21, 66411.7 and 66499.41.

Zones That Allow Homes

Table 16.102-A sets four residential districts and three mixed-use districts. RR and RLD allow up to 9 homes per net acre, RMD up to 25 and RHD up to 40, or 50 where the General Plan says Business/Limited Residential. RLD covers "detached and attached (duplexes and townhouses)" homes; RMD adds "small apartment buildings." The mixed-use districts reach 30 to 90 homes per net acre downtown and on the waterfront. Where the General Plan and the zoning conflict, "the General Plan shall prevail." Six specific plans and several Planned Development areas set their own rules. See the zoning districts page.

House Lots: ADUs and SB 9

Ordinance No. 1890 N.C.(2d), in force since October 8, 2026, allows one junior ADU, one attached or conversion ADU and one detached ADU on a house lot, three units in all. A detached ADU may be 1,200 square feet and 16 feet tall, or 18 feet near a major transit stop, with four-foot side and rear setbacks. A lot with an existing apartment building may add up to eight detached ADUs, never more than its existing units. Approval takes a building permit only, decided within 60 days. The Municode copy of the code, current through December 2025, still prints the old chapter. See the ADUs and SB 9 page.

SB 9 applies under the statutes: two main homes of at least 800 square feet each on a lot in a single-family zone, or a split into two lots of at least 1,200 square feet and 40 percent of the original. On a split lot, the ADU chapter allows "no more than two total dwelling units." The lot size and subdivisions page covers lot splits, Vallejo's own small lot development route down to 2,000 square feet, and its 1989 rule for dividing older built-up lots.

Three or More Homes

Multi-unit residential is permitted in RMD, RHD, NMX, DMX, WMX, NC and CC. RMD buildings may be 50 feet tall and RHD 75 feet, with upper floors above the second limited to 60 percent of the ground floor. Projects of 2 to 10 homes are decided by the Director, 11 to 49 by the Director after a Design Review Board recommendation, and 50 or more by the Planning Commission. Within 2,500 feet of the ferry terminal, the transit centers and the Curtola Park & Ride, a project may add 25 percent density with a minor use permit and needs no parking. The Planning Commission has recommended an Inclusionary Housing Ordinance for projects of 10 or more homes, set for a Council hearing on October 27, 2026. See the three or more homes page.

Parking, Setbacks and Height

Every home needs one off-street parking space, covered in the residential districts, and no guest parking is required. State law bars parking minimums within one-half mile of public transit unless the City makes findings. An RLD house sits 15 feet from the front and 5 feet from the side and rear lot lines and may be 35 feet tall, with lot coverage of 50 percent. RMD and RHD use 5-foot side setbacks for the first two stories and 10 feet above. See the parking, setbacks and height page.

Historic Districts and Hillsides

The City lists three National Register districts, Saint Vincent's Hill, the Architectural Heritage District and the Mare Island Historic Core, and 82 landmarks. New building in a historic district needs a certificate of appropriateness, decided by the Architectural Heritage and Landmarks Commission for a new main structure; ADUs need none. Parcels with an average slope of 15 percent or more need a Hillside Development Permit, and land over 30 percent slope may not be developed. Some hill neighborhoods are Residential View Districts, where neighbors are notified before exterior changes. See the historic districts and hillsides page.

Fees

The FY 2026-2027 Master Fee Schedule lists the City excise tax at $6,689 per new home, the park fee at $11,632 per home in a building of three or more, and the transportation fee at $4,824 per multi-family home. For a fourplex that adds up, with Solano County's multi-family fee, to $29,807 per home before school fees (VanPlex arithmetic). ADUs pay no excise tax or park fee and a $968 Planning fee. The Council revised Building and Planning fees on July 14, 2026. See the permits and fees page.

Where the Code, City Documents and State Law Differ

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

• Municode still prints the old ADU chapter; Ordinance No. 1890 N.C.(2d) replaced it from October 8, 2026. The ordinance controls.
• The new ADU chapter charges impact fees on ADUs of "750 square feet or greater"; Government Code 66311.5 exempts ADUs of 750 square feet or less. The statute controls.
• Section 16.214.03 describes a density bonus of five to 35 percent; Government Code 65915 now reaches 50 percent and more for fully affordable projects. The code ties the bonus to the statute, which controls.
• Table 16.508-B prints parking minimums citywide; Government Code 65863.2 bars them within one-half mile of public transit unless the City makes findings. The statute controls.
• The Residential View District chapter still routes some ADUs to notice and a hearing, while the ADU chapter and state law require approval without one.
• HCD's October 2025 letter says the City's ADU ordinance on file dated from 2018; the City's 2026 staff report says it was adopted in 2021.
• The ADU ordinance's certificate gives final passage as September 8, 2026; the City's project page says September 9.
• Table 16.102-A lists four specific plans and Table 16.210-A lists six; Table 16.301-A cites a Note 27 that does not exist.

Limits of This Guide

The code comes from Municode's "Update 12 - 25," current through December 16, 2025, and later City actions come from the City's own pages and documents on cityofvallejo.net, read on October 10, 2026. The City's other web address, www.vallejo.gov, refused one scripted request, so nothing from that address was used. The Zoning Map, the General Plan, the specific plans and the Waterfront Planned Development Master Plan were not read. Ask the Planning Division whether any ordinance adopted after October 10, 2026 applies, including the Inclusionary Housing Ordinance set for October 27, 2026 and any HCD findings on the new ADU chapter.

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)