ADU fees in Santa Cruz County: $19,702–$31,872 for a 1,000 sq ft backyard unit
The County's own estimator gives about $15.8k–$23.3k in gross County fees for a new detached ADU before ADU waivers. State law removes the impact fees at 750 sq ft or less, and the County says permit review fees are waived at that size too.
20 fee lines · 9 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.
Fee
499 sq ft
750 sq ft
1,000 sq ft
1,200 sq ft
Planning & zoning
Zoning plan checkThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$520
May be waived$520
$520
$520
Environmental planning plan checkThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$0
May be waived$1,330
$1,330
$1,330
Environmental planning inspections
$0
$398
$398
$398
Building permit & plan check
Building permit processing
$1,533
$1,975
$2,324
$2,603
Building plan checkThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$1,364
May be waived$1,758
$2,068
$2,317
Green building plan checkThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$653
May be waived$653
$653
$653
Building permit & inspections
$1,377
$1,774
$2,088
$2,339
Technical training fee
$21
$28
$32
$36
State strong-motion fee (SMIP)
$8
$13
$17
$20
General Plan & technology surcharge
$708
$1,041
$1,168
$1,269
Records management
$15
$15
$15
$15
Public works & encroachment
Public Works roads reviewThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$483
May be waived$483
$483
$483
Public Works drainage reviewThe County says permit review fees are waived for ADUs of 750 sq ft or less, but doesn't list which lines count as review fees. We leave this line out of the low total at those sizes and keep it in the high total.
May be waived$1,370
May be waived$1,370
$1,370
$1,370
Impervious surface (drainage zone) fee
$614
$922
$1,230
$1,476
Impact fees
Roadside improvement feeThe County estimator charges this per new unit without prorating. State law requires impact fees on ADUs over 750 sq ft to be proportional to the primary home, so for those sizes we show the estimator amount × ADU sq ft ÷ primary-home sq ft. That proration is our estimate; the County may apply it differently.
Exempt
Exempt
Est.$1,500
Est.$1,800
Transportation improvement feeThe County estimator charges this per new unit without prorating. State law requires impact fees on ADUs over 750 sq ft to be proportional to the primary home, so for those sizes we show the estimator amount × ADU sq ft ÷ primary-home sq ft. That proration is our estimate; the County may apply it differently.
Exempt
Exempt
Est.$1,500
Est.$1,800
Child care impact feeThe County estimator charges this per new unit without prorating. State law requires impact fees on ADUs over 750 sq ft to be proportional to the primary home, so for those sizes we show the estimator amount × ADU sq ft ÷ primary-home sq ft. That proration is our estimate; the County may apply it differently.
Exempt
Exempt
Est.$54
Est.$65
Affordable housing impact feeCharged per new square foot in the estimator, so it already scales with the ADU's size. State law makes it $0 at 750 sq ft or less.
Exempt
Exempt
$2,000
$2,400
Park impact fee5$7.74 per new sq ft for a single-family lot that never paid a subdivision in-lieu park fee, or $0.95 if it did (lots in subdivisions mapped after April 10, 1973 may have). The County's flow chart lists ADUs under 750 sq ft as exempt.
Exempt
Exempt
$950–$7,740
$1,140–$9,288
School district fee
School impact fee (Live Oak SD + Santa Cruz City Schools)10School districts set this, not the County. We haven't confirmed either district's adopted ADU rate, so we show the statewide Level 1 maximum as an upper bound. ADUs under 500 sq ft are exempt.
Exempt
Up to$4,035
Up to$5,380
Up to$6,456
Modeled total
$4,277–$8,667
$6,167–$16,316
$19,702–$31,872
$22,034–$36,638
Junior ADUs
Since March 2022, JADUs have been eligible for the same County fee waivers as ADUs. 9
Water & sewer
The County lists "Utility connection fees (New Construction ADUs only, proportional to ADU size)". Sewer is charged by the sanitation district for the parcel and water by the water district (for example Soquel Creek Water District or the City of Santa Cruz Water Department). PG&E charges for a separate meter. The estimator run returned $0 for sewer connection on our example parcel. We have not modeled water or sewer connection charges. 6
How the figures were produced
County fee lines come from the County's own Residential Fee Estimator, run on Oct 18, 2026 for a new detached ADU on an existing single-family lot in the Live Oak planning area (Live Oak school district, urban services line, Flood Control Zone 5), with a 2,000 sq ft primary home, 1 new bedroom and 1 new sewer lateral connection. Fees elsewhere in the county differ: drainage-zone and transportation fees only apply in some planning areas. 2
Rules
What you can build in Santa Cruz County
Maximum size
Detached new-construction ADU: 850 sq ft (1 bedroom) or 1,000 sq ft (2+ bedrooms) on parcels under 1 acre; 1,200 sq ft on parcels over 1 acre. Minimum 150 sq ft. 6
Height
Stand-alone ADU inside the Urban Services Line: 16 ft. Outside it: the zone district standard (usually 28 ft). ADU over a detached garage inside the USL: 24 ft (20 ft at the outside wall). 6
Setbacks
Front: zone district standard. Street side and rear: 4 ft. 6
Parking
1 space per ADU, with exceptions (state law exempts many ADUs, for example within half a mile of public transit or conversions). Conversion ADUs: none. 6
Owner occupancy
Not required for an ADU. A JADU requires the owner to live on site. 6
Pre-approved plans
The County links a set of pre-designed ADU plans from its ADU page. 7
Junior ADU (JADU)
Up to 500 sq ft, converted from within the walls of the single-family home; owner must live on site if sanitation is shared. JADUs get the same fee waivers as ADUs (County, since March 2022). 8
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
Santa Cruz County issued 43 ADU building permits in 2025
457 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.
Which County lines count as the "permit review fees" it waives for ADUs of 750 sq ft or less. We show both cases as the low and high totals.
Water and sewer connection charges from the district that serves your parcel.
School district rates: we show the statewide Level 1 maximum instead.
Coastal Development Permit fees for parcels in the Coastal Zone.
Soils report review or waiver ($594 to $1,573 in the County's 2022 estimator guide; not current-year figures, so not modeled).
Conflicting official statements
The County's ADU development-standards table and its code say impact fees are waived under 750 sq ft. State law since Jan 1, 2026 (Gov. Code 66311.5) exempts ADUs of 750 sq ft or less, so we show $0 at exactly 750 sq ft.
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 Santa Cruz County’s official fee schedules comes to $6,167–$16,316 at 750 sq ft and $19,702–$31,872 at 1,000 sq ft. Ranges show fees that may or may not apply to your project.
Does Santa Cruz County 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 Santa Cruz County come to at most $12,794.
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.
How big can an ADU be in Santa Cruz County?
Detached new-construction ADU: 850 sq ft (1 bedroom) or 1,000 sq ft (2+ bedrooms) on parcels under 1 acre; 1,200 sq ft on parcels over 1 acre. Minimum 150 sq ft.
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