Yes: Fremont approves ADUs ministerially under FMC 18.190.005 (last amended by Ord. 02-2026, adopted May 5, 2026) on any lot with an existing or proposed single-family or multifamily home in a residential, mixed-use or planned district. New construction is capped at 1,200 sq ft detached or 1,000 sq ft attached with 4-ft side and rear setbacks; conversions of existing space have no size, height or setback limit; JADUs are capped at 500 sq ft. No parking is required for any ADU, owner-occupancy is not required, and the City charges no development impact fees on ADUs of any size. You file a Ministerial Design Review Permit ($2,000 deposit) plus a separate building permit; the City must decide a complete application within 60 days, and only one preapproved plan is currently valid because the 2025 building codes voided the earlier set on January 1, 2026.
Zoning & Size Requirements [1][2][3][4]
Yes — Fremont allows ADUs. A detached ADU can typically be up to 1,200 sq ft under current California and Fremont zoning rules.
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| Allowed Zones | Any lot with an existing or proposed single-family or multifamily dwelling in a residential or mixed-use zoning district, or in a planned district or planned unit development that allows residential uses (FMC 18.190.005(c)(3)). JADUs are allowed only on lots zoned for single-family residences, inside the single-family home including an attached garage (18.190.005(d)(3)). |
| Max Size (Detached) | 1,200 sq ft of interior livable space for a new detached ADU (FMC 18.190.005(c)(4)(B)(ii)); garages, carports, covered porches, patios and breezeways are not counted. An ADU converted from existing floor area has no size limit (c)(4)(A). Rooftop decks are prohibited (c)(4)(C). |
| Max Size (Attached) | 1,000 sq ft of interior livable space for an attached ADU built as a new addition (FMC 18.190.005(c)(4)(B)(i)). An attached ADU converted from existing floor area has no size limit. |
| Max Size (JADU) | 500 sq ft of interior livable space, contained entirely within the single-family residence including an attached garage, with an efficiency kitchen (FMC 18.190.005(d)(2)). One JADU per lot, in addition to an ADU. |
| Max Height | Detached: 16 ft; 18 ft if the lot is within 1/2 mile walking distance of a major transit stop or high-quality transit corridor, plus 2 ft to match the primary home's roof pitch. Attached: 30 ft or the zone's height limit, whichever is lower. Detached on a multifamily lot: 16 ft, or 18 ft near transit or on a multistory multifamily lot. No height limit for conversions of existing floor area; no minimum or maximum roof pitch (FMC 18.190.005(c)(5)). |
| Max Units | Single-family lot: 1 ADU plus 1 JADU (FMC 18.190.005(c)(2)(A), (d)(1)); under the statewide exemption in (e), one conversion ADU or JADU within existing space plus one new detached ADU of 800 sq ft or less with 4-ft setbacks (Gov. Code 66323). Multifamily lot: conversions of non-livable space for at least 1 and up to 25% of the existing units, plus up to 8 detached ADUs on an existing multifamily lot (never more than the number of existing units) or 2 on a proposed one (18.190.005(e)(3)-(4)). |
Setback Requirements [1][2][3][4]
Fremont requires a rear setback of about 4 ft for a detached ADU, and no additional parking is required. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | 4 ft for an ADU built from new floor area (FMC 18.190.005(c)(6)(B)). None for an ADU within existing living area or an existing accessory structure, or one that replaces a structure in the same location and dimensions; up to 150 sq ft may be added for ingress and egress, and any larger expansion is held to the new-construction setbacks and height (c)(6)(A). |
| Side Setback | 4 ft for new floor area; none for conversions of existing space or same-footprint replacements (FMC 18.190.005(c)(6)). Separately, the building code sets a fire-separation distance: the City's handout says generally 5 ft to the lot line and about 10 ft between the house and a detached ADU, reducible with sprinklers or rated exterior walls (2025 California Residential Code R302.1). |
| Front Setback | The same front-yard setback as the primary dwelling, unless applying it would preclude a state-protected unit under FMC 18.190.005(e), i.e. a conversion ADU/JADU or one new detached ADU of 800 sq ft or less with 4-ft side and rear setbacks (18.190.005(c)(6)(B)). |
| Parking Required | None. No parking spaces are required for any ADU or JADU, and no replacement parking is required when a garage, carport or covered or uncovered parking space is demolished or converted for an ADU (FMC 18.190.005(c)(14); ADU Informational Handout updated 1/5/2026). |
| Owner Occupancy | Not required for the primary dwelling or the ADU (FMC 18.190.005(c)(9)). JADU: required only if the JADU shares a bathroom with the main house, and the owner may live in either unit; not required if the JADU has its own bathroom or the owner is a government agency, land trust or housing organization (18.190.005(d)(5); Gov. Code 66333 as amended by AB 1154, Jan 2026). |
| Min Lot Size | No minimum lot size in FMC 18.190.005. An ADU or JADU does not count toward the lot's allowed density (18.190.005(b)(1)) and, per the City's handout, does not count toward maximum lot coverage. |
Permit Process & Fees [5][6][7][8]
An ADU permit in Fremont goes through a ministerial, by-right review. Typical timeline: Completeness notice within 15 business days and a decision within 60 days of a complete application (FMC 18.190.005(b)(4)); deemed approved if the City misses the 60 days (SB 543, Jan 2026). Preapproved plans are reviewed in 7 business days, standard plans in 15. Permit fees: Limited Design Review for an ADU/JADU: $2,000 deposit billed at cost. Building plan check and inspection are valuation-based (e.g. $967.27 + $5.91 per $1,000 above $100,000) plus 15% Community Planning and 3% technology surcharges (Master Fee Schedule eff. 7/1/2026); preapproved plans $1,000 flat.
| Approval Process | Two applications through the Accela Citizen Access portal: a Ministerial Design Review Permit (no hearing, no discretionary review) and a separate building permit, which may be filed together with a Request for Concurrent Processing; a new address is assigned. The ADU permit must stand alone: applications that bundle ADU work with a remodel of the main house are rejected. Every ADU and JADU, including conversions, needs a building permit (FMC 18.190.005(b)(4)-(5)). |
| Review Timeline | Completeness notice within 15 business days and a decision within 60 days of a complete application (FMC 18.190.005(b)(4)); deemed approved if the City misses the 60 days (SB 543, Jan 2026). Preapproved plans are reviewed in 7 business days, standard plans in 15. |
| Permit Fees | Limited Design Review for an ADU/JADU: $2,000 deposit billed at cost. Building plan check and inspection are valuation-based (e.g. $967.27 + $5.91 per $1,000 above $100,000) plus 15% Community Planning and 3% technology surcharges (Master Fee Schedule eff. 7/1/2026); preapproved plans $1,000 flat. |
| Impact Fees | None. The City's ADU Informational Handout (updated 1/5/2026) states ADUs are not subject to development impact fees regardless of size, and FMC 18.290.110(b) exempts ADU remodels and additions; that is broader than the state floor, which exempts only ADUs of 750 sq ft or less (Gov. Code 66311.5). Utility connection fees (ACWD water, Union Sanitary District sewer, PG&E's required separate electric meter) and Fremont Unified School District fees may still apply. |
| Plan Check | The building plan-check fee covers up to three review cycles (FMC 15.10.090); further cycles cost $147/hr, and expedited plan check at the applicant's request adds $181/hr. Project valuation is set from the City's Exhibit 1 minimum values (RS Means, San Jose modifier), updated each July 1. A preapproved detached plan is reviewed in 7 business days for a flat $1,000; a standard plan set in 15 business days. |
| Pre-Approved Plans | Yes, but the library is thin right now: on January 1, 2026 the 2025 California codes invalidated every plan preapproved under the 2022 cycle, and as of September 2026 one updated plan (1 bed/1 bath, 499 sq ft) is valid while nine 2022-cycle plans (496-1,000 sq ft) await resubmittal. The program covers detached ADUs only; you contract with the plan's designer and still submit site-specific plans, studies and engineering. |
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Construction Costs [9][10][11][12]
Building an ADU in Fremont typically costs $250,000-$460,000 ($300-$480 per sq ft); a garage conversion runs $100,000-$170,000.
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| Average Build Cost | $250,000-$460,000 |
| Cost per Sq Ft | $300-$480 |
| Garage Conversion | $100,000-$170,000 |
| Prefab ADU (Installed) | $150,000-$300,000 |
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Rental Income Potential [13][14][15]
A 2-bedroom ADU in Fremont rents for around $3,100-$3,700/mo, an estimated 7-10% gross annual rent yield on a $250,000-$460,000 detached build renting at $2,600-$3,000/mo; net return is lower after vacancy, property tax and upkeep.
| Avg Rent (1 Bedroom) | $2,600-$3,000/mo |
| Avg Rent (2 Bedroom) | $3,100-$3,700/mo |
| Short-Term Rental | No. An ADU or JADU may not be rented for a term of less than 30 days (FMC 18.190.005(b)(6)). |
| Est. Annual ROI | 7-10% gross annual rent yield on a $250,000-$460,000 detached build renting at $2,600-$3,000/mo; net return is lower after vacancy, property tax and upkeep |
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Recent Law Changes
What's Changed Recently
- Ord. 02-2026 (adopted May 5, 2026), an omnibus zoning amendment, amended FMC 18.190.005 (section 24); the published code is current through this ordinance as of Sept 20, 2026 with no ADU ordinance pending codification
- Jan 1, 2026: the 2025 California Building, Residential, Fire, Plumbing, Mechanical, Electrical, Energy and Green codes took effect; the City voided all 2022-cycle preapproved ADU plans, and only one updated plan is valid as of Sept 2026
- Jan 5, 2026: the City's ADU Informational Handout was reissued, confirming no development impact fees on ADUs of any size, zero parking, and JADU owner-occupancy only where the JADU shares a bathroom
- SB 543 (Jan 2026): ADU applications are deemed approved if the City fails to act within 60 days; AB 1154 (Jan 2026): JADU owner-occupancy may be required only for JADUs that share sanitation facilities with the main home
- July 1, 2026: Master Fee Schedule (Reso. 8672) update: ADU/JADU Limited Design Review $2,000 deposit, Conformance Plan Check $1,000 deposit, building application fee $153
- Ord. 01-2025 (Jan 7, 2025) was the previous amendment of FMC 18.190.005; the codified text now carries the SB 1211 multifamily rules (up to 8 detached ADUs on an existing multifamily lot, no replacement parking for uncovered spaces)
Tips for Building an ADU in Fremont
- Cost basis: Custom Home Fremont ADU cost guide (Feb 19-20, 2026: detached $260K-$460K+, $330-$480/sq ft, garage conversion $100K-$150K, breakdown $86K-$170K), Steadily (updated June 30, 2026: basic detached from $150K-$200K) and ADUscale (June 2026: prefab $120K-$300K installed, Bay Area +25-50%). Rents: HUD FY2026 Small Area FMRs for Fremont ZIPs (1BR $2,940-$3,320, 2BR $3,590-$4,050), Zumper medians (Sept 19, 2026: 1BR $2,688, 2BR $3,122) and RentCafe averages (Aug 31, 2026: 1BR $2,634, 2BR $3,237).
- File the ADU as its own standalone application (Ministerial Design Review Permit plus building permit): the City rejects permits that bundle ADU work with a house remodel, and re-filing restarts the clock.
- A garage or accessory-structure conversion is the fastest path: no size, height or setback limits, no replacement parking, and up to 150 sq ft may be added for a new entrance.
- Fremont charges no development impact fees on ADUs of any size, but budget for PG&E's required separate electric meter, ACWD water and Union Sanitary District sewer connection fees, and Fremont Unified School District developer fees; ask each agency for current rates.
- Before contracting with a designer for a preapproved plan, confirm the plan has been re-approved under the 2025 codes; plans approved in the 2022 cycle cannot be used until they are updated.
- Keep a new detached ADU at 800 sq ft or less with 4-ft side and rear setbacks to qualify as a state-protected unit under FMC 18.190.005(e); it can then be built even where the front-setback rule would otherwise block it.
ADU Builders in Fremont
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Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Fremont Municipal Code Ch. 18.190, section 18.190.005 ADUs and JADUs (current through Ord. 02-2026, May 5, 2026) Municipal Code — Accessed 2026-09-20
- Accessory Dwelling Units (ADUs) | City of Fremont Planning Department — Accessed 2026-09-20
- Informational Handout: Accessory Dwelling Units (ADUs), Single Family Zoning (updated 1/5/2026) | City of Fremont Planning Division Planning Department — Accessed 2026-09-20
- Fremont Municipal Code Ordinance Table (Ord. 06-2023, 01-2025, 02-2026) Municipal Code — Accessed 2026-09-20
- Preapproved Accessory Dwelling Units (ADUs) | City of Fremont Planning Department — Accessed 2026-09-20
- Master Fee Schedule, Resolution No. 8672, fees as amended through July 1, 2026 | City of Fremont Planning Department — Accessed 2026-09-20
- Summary of Development Impact and Affordable Housing Fees (impact fees effective July 1, 2025; housing fees January 1, 2026) | City of Fremont Planning Department — Accessed 2026-09-20
- Fremont Municipal Code Ch. 18.290 Development Impact Fees, section 18.290.110 Exemptions Municipal Code — Accessed 2026-09-20
- ADU Cost Fremont 2026 (published Feb 19, 2026) | Custom Home industry — Accessed 2026-09-20
- Garage Conversions in Fremont 2026: Complete Guide (published Feb 20, 2026) | Custom Home industry — Accessed 2026-09-20
- ADU Housing Laws and Regulations in Fremont (updated June 30, 2026) | Steadily industry — Accessed 2026-09-20
- Prefab and detached ADU cost bands, California (updated June 2026) | ADUscale industry — Accessed 2026-09-20
- HUD FY2026 Small Area Fair Market Rents, Oakland-Fremont, CA HUD Metro FMR Area (ZIPs 94536, 94538, 94539, 94555) Government Data — Accessed 2026-09-20
- Fremont, CA rent research (median listing rents, data as of Sept 19, 2026) | Zumper Market Data — Accessed 2026-09-20
- Average Rent in Fremont, CA (last updated Aug 31, 2026) | RentCafe Market Data — Accessed 2026-09-20
Frequently Asked Questions
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