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Lancaster Multiplex Rules 2026: Duplexes, ADUs, SB 9, Apartments and Fees

Lancaster, in the Antelope Valley of Los Angeles County, publishes one Municipal Code on Municode. Title 17 holds the zoning rules, including the zones, the ADU and SB 9 rules, parking and the design standards. Title 16 holds the subdivision rules, Title 15 the impact fees and Title 13 the drainage fees. This page sums up the routes to two, three, four or more homes on a Lancaster lot, what each allows, and where City text and state law differ. The code was read in Supplement 10 - 2025, whose history table lists ordinances through No. 1143. The seven guide pages below cover each topic in depth.

Lancaster Guide Pages

Start With State Law

Four state laws set the floor Lancaster 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. SB 79 makes larger projects an allowed use near qualifying transit in an "urban transit county," which Government Code 65912.156 defines as "a county with more than 15 passenger rail stations."

HCD's SB 79 advisory lists Los Angeles County among the seven counties where SB 79 took effect on July 1, 2026, so it is in force in Lancaster. It reaches only sites near a "transit-oriented development stop": heavy rail, light rail, commuter rail with at least 48 trains a day, or qualifying bus service. The Lancaster code names no such stop, so check the regional SB 79 map before relying on it. SB 9, ADU law and SB 684 apply on every qualifying lot now.

Lancaster has written its own chapters for ADUs and for both SB 9 routes. The ADU rules are in Chapter 17.41, Article I; the SB 9 two-unit rules in Article III; the SB 9 lot split rules in Chapter 16.17. Several City rules are stricter than the statutes, such as a limit of one ADU and one junior ADU per lot, an owner-occupancy rule for ADUs, and a 3 year occupancy rule after a lot split. In each case the statute controls. The SB 9 statutes apply to every city "whether general law or chartered."

Lancaster in Numbers

The US Census Bureau's Vintage 2025 city file estimates 170,084 people in the City of Lancaster on July 1, 2025, down from a 2020 estimates base of 173,575. In that file Lancaster is the 31st largest city in California, after Garden Grove (170,455) and ahead of Roseville (167,302). Neighboring Palmdale has 161,845 people and Los Angeles County 9,694,934 in the same file.

Most housing decisions sit below the City Council. The Director of Community Development decides site plan reviews and director's reviews, including duplexes and apartments in MDR and HDR, and approves SB 9 projects. The Planning Commission, with "at least five and not to exceed seven commissioners," decides conditional use permits and tentative maps. The City Council decides zone changes, including the Housing Density Overlay, and hears appeals filed within 10 working days.

The Routes to More Homes Compared

Sources: Lancaster Municipal Code 17.08.050, 17.08.030, 17.08.080, 17.20.750, 17.41.014, 17.41.058 and 16.17.050; Government Code 65852.21 and 66499.41.

Zones That Allow Homes

Lancaster's zoning began as Los Angeles County's Ordinance No. 1494, as in force on May 7, 1979, adopted "as the zoning ordinance of the city of Lancaster," and the City has since written its own chapters. Section 17.08.010 names the residential zones: RR, R, MHP, MDR and HDR. The rural zones RR-2.5, RR-1 and SRR allow one home per 100,000, 40,000 and 20,000 square feet. The urban zones R-15,000, R-10,000 and R-7,000 allow one home per lot of that many square feet. MDR has "a density range of 6.6 to fifteen (15) dwelling units per acre" and HDR "15.1 to thirty (30)."

Homes are also allowed in the MU-N, MU-C and MU-E mixed use zones, in the MU-TOD zone covering 186 acres of the Downtown Lancaster Transit Village District, and with a conditional use permit in the C and CPD commercial zones. The Housing Density Overlay raises HDR, C and CPD land to 50 homes per acre. The zoning districts page has the full tables.

House Lots: Duplexes, ADUs and SB 9

Lancaster gives house lots three routes to a second home. The residential uses matrix lists a duplex as "D," director's review, in every RR, R, MDR and HDR column. ADUs are permitted everywhere homes are, by ministerial building permit within 60 days: an attached ADU up to 850 square feet with one bedroom or 1,200 with two or more, a detached ADU up to 18 feet tall, both 25 feet from the front line and 4 feet from the sides and rear. An SB 9 project puts two homes on a lot, each "less than or equal to 800 square feet and more than 500 square feet," one story and 22 feet tall. See the ADUs and SB 9 page.

An SB 9 urban lot split needs a lot of at least 2,400 square feet, gives two lots of at least 1,200 square feet each, and requires 20 feet of street frontage for each new lot. Only individual owners may apply. Urban house lots must be 7,000, 10,000 or 15,000 square feet by zone. The lots and subdivisions page covers parcel maps, tract maps and SB 684.

Three or More Homes

A triplex or fourplex is a multiple-family project, which Lancaster permits with site plan review in MDR and HDR and bars in the rural and urban house zones. An apartment lot must be 6,000 square feet, 60 feet wide and 100 feet deep. By VanPlex arithmetic, four homes at the HDR cap of 30 per acre need 5,808 square feet, so a 6,000 square foot HDR lot can hold a fourplex, while MDR needs 11,616 square feet for four. Buildings of 3 to 15 homes may be 55 feet tall, except 35 feet within 100 feet of a single-family zone. R-7,000 land that meets the infill tests may take up to eight small-lot homes per acre. See the three or more homes page.

Parking, Setbacks and Height

Outside one-half mile of a major transit stop, a house needs 2 spaces in an enclosed garage and so does each home in a duplex, triplex or fourplex. Within that distance "no parking is required," with narrow exceptions. Front setbacks run from 14 feet in R-7,000 to 40 feet in RR-2.5, houses may be 35 feet tall in the urban zones, and lot coverage is 40 to 50 percent. See the parking, setbacks and height page.

Design Standards and Flood Rules

Lancaster's objective design standards apply to every residential project: a 2 by 5 foot wall offset for every 25 feet of street facade, windows or doors on 15 percent of a small building's street facades, and tile roofs. In FEMA flood hazard areas, mapped on the City's adopted Flood Insurance Rate Map of January 6, 1982 and its revisions, a new home's lowest floor must be at or above the base flood elevation. New homes pay a drainage fee before the building permit, and subdivisions file a hydrology study. See the design standards and flood rules page.

Fees

New Lancaster homes pay development impact fees before the building permit: traffic, traffic signal, drainage, park acquisition, park development, administrative offices and corporate yard fees under Chapter 15.64, rewritten by Ordinance No. 1139 on October 28, 2025, plus a park in-lieu fee, a County fire protection fee and, above set thresholds, a VMT fee. The City Council sets every amount by resolution, and building before paying adds "a penalty of twenty-five (25) percent." State law bars impact fees on an ADU of 750 square feet or less. See the permits and fees page.

Limits of This Guide

Every rule on these pages is the Municipal Code text in Supplement 10 - 2025, read on October 9, 2026. The City's own website refused automated requests, so the City's fee schedules, the T.O.D. Zones and Health District Master Plan, and any Council ordinance adopted after Supplement 10 were not read. Ask the City's Development Services staff for the current fee resolution and for any change adopted since the supplement before you budget or design.

Where to Go Next

Related on VanPlex: the SB 79 page, the California impact fees page and the duplex to fourplex guide.

Frequently Asked Questions

Official sources (checked October 2026)