Cities | Folsom

Folsom, California Multiplex Rules 2026: Zoning, Lot Sizes, ADUs, SB 9, Three or More Homes, the Historic District, Permits and Fees

This guide covers the City of Folsom, California, a city of 91,983 people in Sacramento County. The zoning rules are Title 17 of the Folsom Municipal Code, and the code host says the code is current through an ordinance passed on April 28, 2026. Three facts shape a project here. House lots start at 6,000 square feet in the smallest single-family zone and reach 14,500 in the largest. The ADU rules are new, adopted in April 2026, and follow state law closely. And the City website refused the one request made for this guide, so the fee schedules, the zoning map, the General Plan and the specific plan for the land south of Highway 50 were not read. The seven guide pages below cover each topic in depth.

Folsom Guide Pages

Start With State Law

Five state laws set the minimum Folsom 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), second homes on a lot, and junior ADUs a city must allow. SB 684 and SB 1123 allow maps of up to 10 lots with 10 homes. The state density bonus gives extra homes to projects that include affordable homes. And SB 79, the 2025 law on housing near transit, now reaches Sacramento County: HCD, the state housing department, says in its advisory that the law "will take effect on July 1, 2026, in Alameda, Los Angeles, Sacramento, San Francisco, San Mateo, Santa Clara, and San Diego Counties."

California cities are either general law cities, which follow the state's general rules for city government, or charter cities, which have a charter approved by their voters. Folsom is a charter city. Charter Section 1.01 says "As regards municipal affairs, this Charter shall supersede all laws inconsistent therewith." The housing laws above apply to charter cities by their own words: Government Code 65852.21 and 66411.7 define a local agency as a city "whether general law or chartered," and the ADU statutes use the same words.

Folsom has written two of these laws into its code: ADUs in Chapter 17.105, rewritten in 2026, and the density bonus in Chapter 17.102, from 2011 and listed for re-enactment in September 2026. The contents of Titles 16 and 17 list no chapter on SB 9, SB 684 or SB 79, so those statutes apply directly.

Folsom in Numbers

The US Census Bureau's Vintage 2025 city file estimates 91,983 people in the City of Folsom on July 1, 2025. The 2020 estimates base is 80,463, so the city grew by 11,520 people, or 14.3 percent (VanPlex arithmetic), and the 2024 estimate is 88,351. In that file Folsom is the 86th largest city in California, after Hemet (93,649) and ahead of Carson (90,808). Sacramento County has 1,618,460 people, so the City holds 5.7 percent of them (VanPlex arithmetic: 91,983 divided by 1,618,460).

The City reports on its housing plan each year. The City Council agenda of March 24, 2026 lists the "2025 General Plan (and Housing Element) Annual Progress Report," and the agenda of August 11, 2026 lists a contract with Ascent "for the Seventh Cycle Housing Element Update." This guide did not read the Housing Element or those reports, so no permit count or housing target is given here.

The Ways to More Homes Compared

Sources: Folsom Municipal Code 17.06, 17.10.010, 17.16.020, 17.17.030, 17.23.050, 17.52.540 and 17.105; Government Code 65852.21, 65915, 66411.7 and 66499.41.

Zones That Allow Homes

Section 17.10.010 names R-1-L, R-1-ML and R-1-M as "single-family residence districts," R-2 as the two-family district, and R-3, R-4 and R-M as apartment districts. R-3 permits up to four homes per lot and excludes standard single-family detached homes. R-M needs "One thousand seven hundred square feet or more" of lot per home, so a 6,000 square foot lot holds three. R-4 has no density figure in Title 17, so the General Plan sets it. The mixed-use zones of Chapter 17.23 require 12 or 20 homes per acre and allow 30. Planned development permits and specific plans set their own standards. See the zoning districts page.

Lot Sizes and Dividing Land

Most residential zones need 6,000 square feet inside a block and 7,500 on a corner, with 60 feet of width. Title 16 requires a tentative and final parcel map for four or fewer parcels, decided by the Planning Commission, and a tentative and final map for five or more, decided by the City Council after a commission recommendation. A tentative map lasts 24 months, extendable to six years in total. Folsom has no SB 9 chapter, so the statute sets the rules for an urban lot split: two parcels of at least 1,200 square feet, neither under 40 percent of the original lot. See the lot size and subdivisions page.

House Lots: ADUs and SB 9

Chapter 17.105, rewritten by Ordinance 1361 in 2026, allows on a house lot one ADU under the chapter's standards, one converted ADU, one junior ADU and one new detached ADU of up to 800 square feet. A non-mandated ADU may be 850 square feet with one bedroom or 1,000 with two or more. Setbacks are four feet, parking is one space or none near transit, and ADUs of 750 square feet or less pay no City impact fees. The City must decide in sixty days. SB 9 two-unit projects follow Government Code 65852.21 directly. See the ADUs and SB 9 page.

Three or More Homes

Multifamily projects of more than two units go to the Planning Commission for design review, unless they qualify for staff review under the objective standards of Section 17.06.045 in three overlays. Section 17.104.030 requires for-sale projects of ten or more homes to include 10 percent affordable homes, or pay an in-lieu fee. A fourplex needs 9 parking spaces in R-3, R-M and R-4. The 2011 density bonus chapter prints a 35 percent maximum where the statute now allows 50. See the three or more homes page.

Parking, Setbacks and Height

Front yards are 20 feet in most zones and 35 feet in R-1-L. Single-family side yards are five feet on one side and eleven on the other. R-1-ML and R-1-M allow two and one-half stories up to 35 feet, and R-M and R-4 four stories up to 50 feet. Coverage runs from 30 percent in R-1-L to 60 percent in R-M and R-4. A house needs "two covered parking spaces per unit," and covered means a fully enclosed structure that matches the house. Hillside lots cap paving and buildings at sixty percent of the lot. See the parking, setbacks and height page.

The Historic District

Chapter 17.52 covers the old town around Sutter Street. A Historic District Commission of 7 members reviews new buildings and decides use permits and variances there. Residential lots need 7,000 square feet, multifamily projects need a use permit and may not exceed 12 units, ADUs follow listed architectural styles, and buildings fifty or more years old need demolition review. Ordinance No. 1375, re-adopting the 2025 district amendments, is listed for adoption on August 11, 2026. See the historic district page.

Permits and Fees

Design review approvals last two years, use permits one year, and appeals are due within ten days. Fees are set by City Council resolution; the April 28, 2026 agenda lists Resolution No. 11601, an updated impact and connection fee schedule, and Resolution No. 11604, the user fee adjustment, whose amounts were not read. The code still prints a residential construction tax of $400 per single-family home from 1978. See the permits and fees page.

Land South of Highway 50

In 2004 Folsom voters added Charter Section 7.08, "Local Control of Land South of Highway 50," for the land "bounded by Highway 50, White Rock Road, Prairie City Road and the El Dorado County Line." It required a new water supply, a transportation funding plan, "30 percent of the Area to be maintained as natural open space," a school plan and a General Plan Amendment before annexation. The land is now the Folsom Plan Area, defined in Section 3.120.020 as the property "south of Highway 50 within the Folsom plan area specific plan adopted by the city council on June 28, 2011, in Resolution No. 8863." Its zones are written in that specific plan, which is on the City website and was not read. The code chapters that apply there are the plan area fee chapters, 3.120 and 3.130, and the design standards for the town center overlay.

How Current the Code Is

The code was read on October 11, 2026, one page at a time with pauses, from the code host. The chapters saved were Title 17, Chapters 17.02, 17.06, 17.08, 17.10 to 17.18, 17.23, 17.37, 17.38, 17.52, 17.56 to 17.58, 17.60, 17.62, 17.68, 17.90, 17.102, 17.104, 17.105 and 17.110; Title 16, Chapters 16.04 to 16.36, 16.60, 16.70 and 16.80; Chapters 3.80, 3.90, 3.120, 3.130, 14.27, 14.30 and 14.33; the Charter; and the disposition of ordinances table.

Source: Folsom Municipal Code front page and disposition of ordinances table, read October 11, 2026; City Council agendas of August 11 and September 22, 2026.

These are the ordinances that shape the housing rules on these pages.

Sources: history notes at the end of the cited sections of the Folsom Municipal Code; the disposition of ordinances table; the City Charter; and City Council agendas of January 13, April 14, August 11 and September 22, 2026.

Recent City Council Actions

• January 13, 2026. The agenda lists Ordinance No. 1359 on inclusionary in-lieu fees for adoption, and Resolution No. 11510 setting in-lieu fee amounts for for-sale projects.
• March 10 and 24, 2026. The agendas list the public hearing on Ordinance No. 1361, the ADU chapter, and on March 24 the 2025 General Plan and Housing Element annual progress report.
• April 14, 2026. The agenda lists Ordinance No. 1361 for second reading and adoption.
• April 28, 2026. The agenda lists Resolutions No. 11601 and 11604 on City fees, and Ordinance 1369, the last ordinance in the code.
• June 9 and 23, 2026. The agendas list the Toll Brothers at Alder Creek project "in the Folsom Plan Area," with a "Small-Lot Vesting Tentative Subdivision Map, Planned Development Permit, Inclusionary Housing Plan," continued from June 9 to June 23.
• July 14 and August 11, 2026. The agendas list Ordinance No. 1375 on the historic district for introduction and adoption, and on August 11 a contract for the Seventh Cycle Housing Element Update.
• September 8 and 22, 2026. The agendas list Ordinance No. 1374, repealing and re-enacting the density bonus chapter, for introduction and adoption, and on September 22 a "Housing Program Implementation Workshop."
• October 13, 2026. The agenda lists a contract to "Complete the Folsom Zoning Code Update Project" and the Folsom Plan Area public facilities fee nexus study, continued to December 8, 2026.

These are agenda listings published before each meeting. The agendas record no votes, and minutes and staff reports are on the City website, which was not read. The Planning Commission and Historic District Commission meeting lists on the agenda system post video but no agendas.

Where the Code, City Documents and State Law Differ

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

• Detached ADU height. Section 17.105.150 caps a larger detached ADU at the lesser of 25 feet or the house height. Government Code 66321 requires at least 16 feet.
• ADUs in mixed-use zones. Table 17.23.030 marks second dwelling units "N." Section 17.105.010 and Government Code 66314 allow them on multi-unit parcels.
• Garage conversions. Section 17.57.030 blocks a garage conversion on a lot with too few covered spaces. Section 17.105.180 and Government Code 66314 require no replacement parking for an ADU.
• Density bonus. Chapter 17.102 prints a 35 percent maximum. Government Code 65915 allows up to 50 percent, and Ordinance No. 1374 is listed to replace the chapter.
• Historic district ADUs. Section 17.52.540 doubts that a second unit can be designed in The Preserve, and Section 17.52.500 uses an 800 square foot and 16-foot trigger for design standards. Chapter 17.105 and Government Code 66323 govern.
• Parking pointer. Section 17.57.040 sends historic district parking to Section 17.57.090, which covers bicycles.
• Variance life. Section 17.62.050 voids an unused variance in sixty days; Section 17.62.060 applies the one-year use permit rule.
• Parkland formula. Section 16.32.040 shows 2.77 persons per single-family home in its example and 2.92 in its table.
• The district list. Section 17.10.010 omits the MU, SP, E and H-D districts created by other chapters.
• Old ADU section numbers. Section 16.04.050 still cites Government Code 65852.2.

Limits of This Guide

The City website, folsom.ca.us, answered 403 with a page titled "Access Denied" to the one request made before this guide began. That is a refusal, and no further request was sent to it. As a result these were not read: the fee schedules and fee resolutions, the zoning map, the General Plan, the Housing Element, the Folsom Plan Area Specific Plan, the objective design standards, the historic district design guidelines, staff reports, minutes and the City's ADU and SB 9 handouts and forms.

Also not read: the SB 79 map of transit stops, the fire hazard severity zone maps, the hillside areas map, school district fees, the diagrams inside the code, and the chapters of the code not listed above. City Council agendas from January 13 to October 13, 2026 were read. Ask the Planning Division which standards and fees apply to your lot and whether a newer ordinance is in force.

Where to Go Next

Related on VanPlex: the California SB 9 page, the California impact fees page and the Daly City guide.

Frequently Asked Questions

Official sources (checked October 2026)