ADU fees in Hayward: $12,592–$24,195 for a 1,000 sq ft backyard unit
Hayward bases most of its building fees on a valuation it publishes per sq ft, so we can model the whole permit. An ADU of 750 sq ft or more pays a $3,379 park impact fee. A sewer connection fee of $5,825 per ADU applies where a connection is needed.
14 fee lines · 2 official sources · checked Oct 18, 2026 · Sources · Calculator
Modeled fees by ADU size
Detached ADU, 2,000 sq ft main home (example assumption), law in force today. Bars: solid = fees that apply, hatched = fees that may apply.
Each fee with its official source (numbers link to the source list). Est. = computed by us from the official rate; May apply = high total only; Up to = statewide cap, district may charge less.
Building inspection fee (valuation table)1Valuation = ADU sq ft × $198.13, Hayward's minimum for R-3 (one- and two-family) type VB wood-frame construction, then the City's fee table. Other construction types cost more; Hayward uses the higher of your stated valuation and its table.
Park impact fee (ADU 750+ sq ft)1Hayward's set amount for an ADU of 750 sq ft or more. Under state law, $0 at exactly 750 sq ft or less.
Exempt
Exempt
$3,379
$3,379
School district fee
School fee (Hayward Unified; statewide cap shown)3
Exempt
Up to$4,035
Up to$5,380
Up to$6,456
Utility connections
Sewer connection fee (ADU, where applicable)1Effective September 1, 2026, per ADU "where applicable"; counted in the high total only.
May apply$5,825
May apply$5,825
May apply$5,825
May apply$5,825
Modeled total
$5,913–$12,136
$7,563–$17,821
$12,592–$24,195
$13,670–$26,349
How Hayward’s ADU fees changed
Only lines we can read in an earlier official schedule. Each figure is our computation for a 1,000 sq ft detached ADU next to a 2,000 sq ft main home (Example assumption), using the same rules as the rest of this page. All fee changes →
Sewer connection fee (ADU, where applicable) May apply
$5,295
$5,825
+$530
+10.0%
These lines
$5,295
$5,825
+$530
+10.0%
2 quoted lines from the earlier schedule
Sep 1, 2025 Sep 1, 2026
(3) Accessory Dwelling Units $5,295.00 $5,825.00
Rules
What you can build in Hayward
Maximum size
State floor: cities must allow at least 850 sq ft (1,000 sq ft with 2+ bedrooms); detached ADUs can be capped at 1,200 sq ft. Local rule not captured yet.4
Height
State floor: 16 ft detached (18 ft near transit or on a multifamily lot, +2 ft for roof pitch); 25 ft attached. Local rule not captured yet.4
Setbacks
State limit: no more than 4 ft side and rear. Local rule not captured yet.4
Parking
State limit: at most 1 space per ADU or bedroom, and none within ½ mile of transit and in other cases. Local rule not captured yet.4
Owner occupancy
State law: cities can't require the owner to live on site for an ADU (JADUs: owner on site if sanitation is shared). Local rule not captured yet.4
Pre-approved plans
State law: every city must run a program to pre-approve ADU plans (Gov. Code 65852.27). Local rule not captured yet.4
State law
Why a 750 sq ft ADU pays no impact fees
California bars impact fees on ADUs of 750 sq ft or less of interior livable space. Above that, they must be proportional to the main home’s size; we assume 2,000 sq ft unless you enter yours. School fees start at 500 sq ft. From January 1, 2027, SB 1117 limits impact fees to the area over 750 sq ft. How the state rules work →
ADU permits issued
Hayward issued 56 ADU building permits in 2025
384 from 2018 to 2025, as the jurisdiction reported to the state in its Housing Element Annual Progress Reports (Table A2, ADU rows; may include JADUs). “–” means no ADU rows were reported that year.
We assume type VB (wood-frame) construction for the valuation; type VA's minimum is $211.39/sq ft, and Hayward uses your stated valuation if it's higher.
State SMIP and building standards fees, solid waste review and landscape inspection aren't included.
School district rate not captured; shown at the statewide cap.
Local size, height and parking rules not captured yet; the state minimums apply.
The Governor approved SB 1117 (Chapter 809, Statutes of 2026) on September 29, 2026. It amends Gov. Code 66311.5: on lots with up to two ADUs, impact fees on an ADU over 750 sq ft must still be proportional to the primary home, and may only be charged on the area over 750 sq ft. Regular 2026 statutes take effect January 1, 2027. Until then, fees on a larger ADU are figured on its full size. Our calculator has a 2027 setting that shows the difference.
The Department of Housing and Community Development updated its ADU Handbook to reflect the laws that took effect January 1, 2026. Its proportional-fee example: a 1,000 sq ft ADU next to a 2,000 sq ft home pays 50% of the fee a new home would pay. Our models use 2,000 sq ft as the example primary-home size unless you enter your own.
On January 28, 2026 the State Allocation Board raised the statewide maximum Level 1 developer fee for residential construction from $5.17 to $5.38 per sq ft (+4.06%). School districts collect it on ADUs of 500 sq ft or more, at their own adopted rate up to this cap (higher Level 2/3 fees need extra findings). Where we haven't confirmed a district's rate, we use $5.38 as the upper bound.
SB 543 (Chapter 520, Statutes of 2025) took effect January 1, 2026. It restates the impact-fee rule in Gov. Code 66311.5: no impact fees on an ADU of 750 sq ft of interior livable space or less, or a JADU of 500 sq ft or less; above that, fees must be proportional to the primary home. It also caps JADUs at 500 sq ft of interior livable space. Many city documents still cite the older section numbers (65852.2 or 66324).
For a detached ADU with a 2,000 sq ft main home (an example assumption), our model of Hayward’s official fee schedules comes to $7,563–$17,821 at 750 sq ft and $12,592–$24,195 at 1,000 sq ft. Ranges show fees that may or may not apply to your project.
Does Hayward charge impact fees on a 750 sq ft ADU?
No. California Government Code section 66311.5 bars impact fees on an ADU of 750 sq ft of interior livable space or less (500 sq ft or less for a JADU). Above 750 sq ft, impact fees must be proportional to the size of the main home. At 1,000 sq ft, the impact fees we model for Hayward come to at most $3,379.
Do school fees apply to an ADU?
Only at 500 sq ft or more. School districts charge their adopted developer fee per sq ft, capped at the State Allocation Board’s Level 1 maximum ($5.38 per sq ft since January 28, 2026) unless they qualify for higher levels.
A local agency, special district, or water corporation shall not impose any impact fee upon the development of an accessory dwelling unit that has 750 square feet of interior livable space or less