Hayward approves ADUs and JADUs ministerially through a checklist review under Hayward Municipal Code Sec. 10-1.2740 and Gov. Code 66314-66331, applied via the Development Services Department's April 2026 ADU checklists. A new detached ADU may be up to 1,200 sq ft of interior livable space with 4-ft side and rear setbacks and a 16-ft height limit (18 ft within 1/2 mile of a major transit stop); an attached ADU is capped at 50% of the primary home's floor area, and conversions of existing permitted structures have no size or setback limit. Planning's ADU zoning conformance permit is a $498 fixed fee, building permit fees are valuation-based, and a new detached unit that needs its own water meter should budget roughly $21,000 in water and sewer connection charges. The former Reach Code all-electric rule for detached ADUs was repealed by Ordinance 25-12 in December 2025; ADUs 750 sq ft or less pay no impact fees under Gov. Code 66311.5.
Zoning & Size Requirements [1][2][3][4][5]
Yes — Hayward allows ADUs. A detached ADU can typically be up to 1,200 sq ft under current California and Hayward zoning rules.
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| Allowed Zones | Any lot with an existing or proposed single-family home (SFR checklist item 1) or with two or more attached multifamily units (MFR checklist item 1), in residential and mixed-use zones per Gov. Code 66323; JADUs only with a single-family home and never on multifamily lots (JADU checklist, July 2026) |
| Max Size (Detached) | 1,200 sq ft of interior livable space for a newly built detached ADU (SFR/MFR checklists, April 2026, item 5/6); no size limit for conversions of existing, permitted structures; state law guarantees at least 850 sq ft (studio/1BR) or 1,000 sq ft (2+BR) (Gov. Code 66321(b)) |
| Max Size (Attached) | 50% of the total floor area of the primary dwelling (SFR checklist item 5b), but never less than 800 sq ft under Gov. Code 66321(b)(3) and 850/1,000 sq ft under 66321(b)(2); conversions of existing permitted space have no size limit |
| Max Size (JADU) | 500 sq ft within the existing or proposed single-family home (attached garage counts), with up to 150 sq ft added only for entry/egress; detached structures cannot become JADUs; an efficiency kitchen is required (JADU checklist, July 2026, items 4-6) |
| Max Height | Detached: 16 ft, or 18 ft within 1/2 mile walking distance of a major transit stop or high-quality transit corridor (and, on multifamily lots, where the main building is multi-story). Attached: the underlying zoning district's height limit. No height limit for conversions. Measured to the roof's highest point (flat), top roof line (mansard) or mid-point of the highest gable (pitched) (SFR checklist item 6) |
| Max Units | Single-family lot: 1 ADU (attached or detached) + 1 JADU (SFR checklist item 3). Existing multifamily lot: conversions of non-living space up to 25% of existing units (minimum one) plus detached ADUs up to the existing unit count or 8, whichever is less; proposed multifamily: 2 detached ADUs (MFR checklist, April 2026, items 3-4; Gov. Code 66323) |
Setback Requirements [1][2][3][4][5]
Hayward requires a rear setback of about 4 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is not required — you can rent it out without living on the property.
| Rear Setback | 4 ft for a newly built ADU; none for conversions of existing, permitted structures (SFR checklist item 4) |
| Side Setback | 4 ft interior side and street side for new construction; 5 ft separation from other structures on the lot (SFR checklist item 4; the 2025 checklist said 6 ft) |
| Front Setback | Conform to the underlying zoning district (SFR checklist item 4c); state law bars a front setback that would prevent an 800 sq ft ADU with 4-ft side/rear setbacks (Gov. Code 66321(b)(3)) |
| Parking Required | Hayward's April 2026 ADU checklists contain no parking item. State law caps any local requirement at one space per unit or bedroom, whichever is less, and bars it within 1/2 mile walking distance of public transit (Hayward and South Hayward BART, AC Transit), for conversions, in historic districts and other cases (Gov. Code 66314(b)(10), 66322); a garage converted or demolished for an ADU need not be replaced. Confirm with the Planning Division for a new detached unit far from transit |
| Owner Occupancy | Not required for ADUs (Gov. Code 66315). JADU: required only when the JADU shares a bathroom with the main house, with a deed restriction recorded with the Alameda County Clerk-Recorder before permit issuance (JADU checklist, July 2026, item 11; AB 1154) |
| Min Lot Size | None stated in Hayward's checklists; state law bars a minimum lot size that would block an 800 sq ft ADU (Gov. Code 66321(b)(3)) |
Permit Process & Fees [6][7][8][9][10]
An ADU permit in Hayward goes through a ministerial, by-right review. Typical timeline: City handout: first review in 15 business days, resubmittals in 10 business days; state law requires a decision within 60 days of a complete application or the ADU is deemed approved (Gov. Code 66317, SB 543, Jan 2026). Permit fees: Planning's ADU Zoning Conformance Permit is a $498 fixed fee (FY2026-27 Master Fee Schedule, eff. July 1, 2026); building permit fees are valuation-based (about $2,917 inspection fee on $250,000 plus plan-check, review and issuance multipliers of about 2.3x) plus $158 housing review and $340 address.
| Approval Process | Ministerial review: submit the building permit with the completed ADU checklist (SFR, MFR or JADU) through the Hayward e-Permit Portal under 'Residential - Accessory Dwelling Unit (ADU)'; projects using a plan set from the ADU Plans Gallery use the 'Using Pre-Approved ADU Plans' application with site-specific site plan and foundation details. A plan review fee is due before review; other fees at issuance |
| Review Timeline | City handout: first review in 15 business days, resubmittals in 10 business days; state law requires a decision within 60 days of a complete application or the ADU is deemed approved (Gov. Code 66317, SB 543, Jan 2026) |
| Permit Fees | Planning's ADU Zoning Conformance Permit is a $498 fixed fee (FY2026-27 Master Fee Schedule, eff. July 1, 2026); building permit fees are valuation-based (about $2,917 inspection fee on $250,000 plus plan-check, review and issuance multipliers of about 2.3x) plus $158 housing review and $340 address |
| Impact Fees | ADUs 750 sq ft or less pay no impact fees (Gov. Code 66311.5). Above that Hayward charges a $3,379 park impact fee for an ADU (FY2026-27 schedule item 43a) plus Hayward USD school fees; affordable-housing fees apply only if the project adds two or more units. Water and sewer connection charges are not impact fees and apply at any size: sewer $5,825 per ADU from Sept 1, 2026, and a new 5/8-in water meter $8,631 facilities fee plus about $6,560 for a 3/4-in service line |
| Plan Check | Checklist-based staff review; a 'yes' or 'n/a' on every checklist item qualifies the project for ministerial ADU clearance, a 'no' triggers further review. Plans must be prepared by a designer, architect or engineer familiar with the California Residential Code (SFR checklist item 2); multifamily ADU plans require a California-licensed architect or engineer (MFR checklist item 2) |
| Pre-Approved Plans | Yes. Hayward's ADU Plans Gallery (hayward.aduaccelerator.org) lists designer plan sets pre-reviewed by the city; the plans are purchased from the designer, not free, and still need a site-specific site plan, foundation details and the ADU checklist |
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Construction Costs [11][12][13]
Building an ADU in Hayward typically costs $200,000-$425,000 ($300-$475 per sq ft); a garage conversion runs $120,000-$225,000.
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| Average Build Cost | $200,000-$425,000 |
| Cost per Sq Ft | $300-$475 |
| Garage Conversion | $120,000-$225,000 |
| Prefab ADU (Installed) | $150,000-$300,000 |
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Rental Income Potential [14][15][16]
A 2-bedroom ADU in Hayward rents for around $2,550-$3,100/mo, an estimated Gross rental yield of roughly 7-10% on build cost before vacancy, taxes and upkeep (e.g., $2,500/mo on a $325,000 ADU is about 9%).
| Avg Rent (1 Bedroom) | $2,000-$2,500/mo |
| Avg Rent (2 Bedroom) | $2,550-$3,100/mo |
| Short-Term Rental | No. ADUs and JADUs may not be rented for less than 30 days; the owner acknowledges this on the checklist (SFR checklist item 13, JADU checklist item 9) |
| Est. Annual ROI | Gross rental yield of roughly 7-10% on build cost before vacancy, taxes and upkeep (e.g., $2,500/mo on a $325,000 ADU is about 9%) |
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Recent Law Changes
What's Changed Recently
- Sept 20, 2026 re-verification: Reach Code all-electric claim removed (Ord. 25-12, adopted Dec 2, 2025, repealed the gas-ban Ordinance 22-11, unenforced since March 2024); planning fee updated from $328 to the $498 zoning conformance permit (FY2026-27 schedule); building separation 6 ft to 5 ft, 18-ft transit-area height and utility connection charges added from the April 2026 checklists; rents raised to HUD FY2026 SAFMR and Sept 2026 market data
- April-July 2026: Development Services reissued the SFR, MFR and JADU ADU checklists citing the renumbered Gov. Code ADU sections (66314 et seq. and 66333 et seq.); the utilities checklist (Sept 2025) lists $19,701 in typical water/sewer fees for a new detached ADU
- FY2026-27 Master Fee Schedule (effective July 1, 2026): ADU zoning conformance permit $498, ADU park impact fee $3,379 (750 sq ft or more per the city; state law exempts 750 sq ft or less), sewer connection charge per ADU $5,825 from Sept 1, 2026
- SB 543 (Jan 1, 2026): ADU applications are deemed approved if the city does not act within 60 days of a complete application (Gov. Code 66317)
- AB 1154 (Jan 1, 2026): JADU owner-occupancy may only be required when the JADU shares a bathroom with the primary dwelling; Hayward's July 2026 JADU checklist follows this
- HCD posted a technical-assistance letter on Hayward's ADU ordinance dated Oct 8, 2025; Hayward's checklists now apply the state code sections directly
Tips for Building an ADU in Hayward
- Cost basis: Custom Home's Hayward ADU page (accessed Sept 20, 2026) gives detached $200K-$425K, garage conversions $120K-$225K and $300-$475/sq ft; ADUscale (June 2026) puts prefab at $120K-$250K plus site work in the Bay Area. Rents: HUD FY2026 SAFMRs for 94541-94545 are $2,330-$2,580 (1BR) and $2,850-$3,150 (2BR); Zumper (Sept 20, 2026) $2,034/$2,575 and RentCafe (Aug 31, 2026) $2,210/$2,698
- Budget the utilities before the design: a new detached ADU (or a conversion adding more than 150 sq ft) needs its own water meter, and the city's utilities checklist totals $19,701 at Sept 2025 rates (about $21,000 after the Sept 1, 2026 increases); a conversion adding 150 sq ft or less usually just upsizes the meter to 3/4 in for about $4,517
- A separate PG&E electric meter is required whenever the ADU includes new permitted space; only conversions wholly inside existing permitted space are exempt (SFR checklist item 17)
- Keep a new detached ADU at 750 sq ft or less to avoid the $3,379 park fee and Hayward USD school fees; state law exempts 750 sq ft or less, while the city's checklist starts fees at 750, so confirm the treatment of exactly 750 sq ft with Planning
- Attached ADUs need a full 1-hour fire-rated wall from footing to roof deck and no internal door to the main house (CRC R302.2; SFR checklist items 7-8); no shared return air between units (CMC 311.4)
- Conversions of existing permitted structures (garage, workshop) have no size, setback or height limit under the checklist and no parking requirement under state law; a JADU inside the house can add up to 150 sq ft for its entry
- The city's 2023 process handout still says new detached ADUs must be all-electric; that Reach Code rule was repealed by Ordinance 25-12 and no longer appears on the April 2026 checklist, but the 2025 California Energy Code (in force Jan 1, 2026) applies to your Title 24 report
ADU Builders in Hayward
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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.
- Accessory Dwelling Unit Checklist - Single-Family Residential (Updated April 2026), City of Hayward Development Services Planning Department — Accessed 2026-09-20
- Accessory Dwelling Unit Checklist - Multi-Family Residential (Updated April 2026), City of Hayward Planning Department — Accessed 2026-09-20
- Junior Accessory Dwelling Unit Checklist (Updated July 2026), City of Hayward Planning Department — Accessed 2026-09-20
- ADU and JADU | City of Hayward (updated June 9, 2026) Planning Department — Accessed 2026-09-20
- Gov. Code 66314-66331 (ADU approvals, as amended by SB 543 eff. Jan 1, 2026) state_statute — Accessed 2026-09-20
- Adopted Master Fee Schedule FY 2026-2027, effective July 1, 2026, City of Hayward fee_schedule — Accessed 2026-09-20
- The Accessory Dwelling Unit (ADU) Process handout (Oct 2023), City of Hayward Planning Department — Accessed 2026-09-20
- Staff report, Introduction of Revised Electrification Reach Code Ordinance (Nov 18, 2025) and adoption as Ordinance 25-12 (Dec 2, 2025), Hayward City Council ordinance — Accessed 2026-09-20
- Gov. Code 66311.5 (ADU impact fees, renumbered by SB 543 eff. Jan 1, 2026) state_statute — Accessed 2026-09-20
- HCD Technical Assistance Letter - City of Hayward ADU Ordinance (Oct 8, 2025) state_agency — Accessed 2026-07-10
- ADU Construction in Hayward, CA | Custom Home industry — Accessed 2026-09-20
- ADU Cost Fremont 2026 (East Bay cost guide, Feb 19, 2026) | Custom Home industry — Accessed 2026-09-20
- Prefab ADU cost guide (June 2026) | ADUscale industry — Accessed 2026-09-20
- HUD FY2026 Small Area Fair Market Rents, Oakland-Fremont HMFA, ZIPs 94541-94545 Government Data — Accessed 2026-09-20
- Hayward, CA Rent Research | Zumper (Sept 20, 2026) Market Data — Accessed 2026-09-20
- Average Rent in Hayward, CA | RentCafe (Aug 31, 2026) Market Data — Accessed 2026-09-20
Frequently Asked Questions
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