800 sq ft ADU · checked Oct 18, 2026
800 sq ft ADU fees in Santa Cruz: $10,980–$17,684, $3,936 more than at 750 sq ft
At 800 sq ft an ADU crosses the 750 sq ft line, so Santa Cruz’s impact fees apply in proportion to the main home: $3,244 with a 2,000 sq ft house, against $0 at 750 sq ft. From January 1, 2027, SB 1117 limits them to the 50 sq ft over 750, which our model puts at $203.
750 vs 800
What the extra 50 sq ft changes in Santa Cruz
- Building permit (valuation table): $2,327 at 750 sq ft → $2,360 at 800 sq ft
- Electrical permit (17% of building permit): $396 at 750 sq ft → $401 at 800 sq ft
- Mechanical permit (7% of building permit): $163 at 750 sq ft → $165 at 800 sq ft
- Plumbing permit (16% of building permit + $64 issuance): $372 at 750 sq ft → $378 at 800 sq ft
- Green Building Program (1% of valuation): $1,650 at 750 sq ft → $1,760 at 800 sq ft
- Planning plan check ($401 + $4 per $1,000 valuation): $1,061 at 750 sq ft → $1,105 at 800 sq ft
- General Plan maintenance fee for ADUs (0.61% of valuation): $1,006 at 750 sq ft → $1,074 at 800 sq ft
- Technology surcharge (6%): $272 at 750 sq ft → $278 at 800 sq ft
- Public safety impact fee: police: $0 at 750 sq ft → $1,352 at 800 sq ft (exempt at 750)
- Public safety impact fee: fire: $0 at 750 sq ft → $1,504 at 800 sq ft (exempt at 750)
- Childcare impact fee: $0 at 750 sq ft → $388 at 800 sq ft (exempt at 750)
- Parks & recreation facilities tax ($3 per sq ft): $0–$2,250 at 750 sq ft → $0–$2,400 at 800 sq ft
- School impact fee (Santa Cruz City Schools): $0–$4,035 at 750 sq ft → $0–$4,304 at 800 sq ft
Staying at 750 sq ft would save about $3,936 in fees under today’s law.
Line by line: 750 sq ft vs 800 sq ft, now and under SB 1117
Detached ADU, 2,000 sq ft main home (example assumption). The 2027 column applies SB 1117, which limits impact fees to the area over 750 sq ft.
| Fee | 750 sq ft (2026) | 800 sq ft (2026) | 800 sq ft (from 2027) |
|---|---|---|---|
| Planning & zoning | |||
| Planning plan check ($401 + $4 per $1,000 valuation) | Est.$1,061 | Est.$1,105 | Est.$1,105 |
| General Plan maintenance fee for ADUs (0.61% of valuation) | Est.$1,006 | Est.$1,074 | Est.$1,074 |
| Building permit & plan check | |||
| Building permit (valuation table) | Est.$2,327 | Est.$2,360 | Est.$2,360 |
| Electrical permit (17% of building permit) | $396 | $401 | $401 |
| Mechanical permit (7% of building permit) | $163 | $165 | $165 |
| Plumbing permit (16% of building permit + $64 issuance) | $372 | $378 | $378 |
| Plumbing permit issuance | $64 | $64 | $64 |
| Energy (Title 24) review | $152 | $152 | $152 |
| Green Building Program (1% of valuation) | Est.$1,650 | Est.$1,760 | Est.$1,760 |
| Technology surcharge (6%) | $272 | $278 | $278 |
| Construction taxes | |||
| Parks & recreation facilities tax ($3 per sq ft) | May apply$2,250 | May apply$2,400 | May apply$2,400 |
| Impact fees | |||
| Public safety impact fee: police | Exempt | $1,352 | $84 |
| Public safety impact fee: fire | Exempt | $1,504 | $94 |
| Childcare impact fee | Exempt | Est.$388 | Est.$24 |
| School district fee | |||
| School impact fee (Santa Cruz City Schools) | Up to$4,035 | Up to$4,304 | Up to$4,304 |
| Modeled total | $7,463–$13,748 | $10,980–$17,684 | $7,939–$14,643 |
State law
Why 800 sq ft is the size every city must allow
Local limits on lot coverage, floor area ratio, open space and minimum lot size can’t stop an 800 sq ft ADU with 4 ft side and rear setbacks, and a detached unit of up to 800 sq ft must be approved ministerially alongside a junior ADU.
Santa Cruz: Non-exempt detached ADU: 10% of net lot area up to 1,200 sq ft, or 850 sq ft (studio or 1 bedroom) / 1,000 sq ft (2+ bedrooms). A Statewide Exemption detached ADU: up to 800 sq ft.
Gov. Code §66321(b)(3)
size based upon a percentage of the proposed or existing primary dwelling, or limits on lot coverage, floor area ratio, open space, front setbacks, and minimum lot size, for either attached or detached dwellings that does not permit an accessory dwelling unit with at least 800 square feet of interior livable space and with four-foot side and rear yard setbacks to be constructed in compliance with all other local development standards.
Gov. Code §66323(a)(2)
One detached, new construction, accessory dwelling unit that does not exceed four-foot side and rear yard setbacks for a lot with a proposed or existing single-family dwelling.
Gov. Code §66323(a)(2)(A)
A total floor area limitation of not more than 800 square feet of livable space.
Quoted from Government Code, Title 7, Division 1, Chapter 13 (Accessory Dwelling Units), incl. §66311.5 (opens in new tab), checked Oct 18, 2026.
FAQ
Questions about 800 sq ft adu in Santa Cruz
How much are the fees for an 800 sq ft ADU in Santa Cruz?
Our model of Santa Cruz’s official schedules comes to $10,980–$17,684 for a detached 800 sq ft ADU with a 2,000 sq ft main home, compared with $7,463–$13,748 at 750 sq ft.
Does an 800 sq ft ADU pay impact fees in Santa Cruz?
Yes: $3,244 in our model, because 800 sq ft is over the 750 sq ft exemption. Fees must be proportional to the main home; a larger house means a smaller share. From 2027, SB 1117 limits them to the 50 sq ft over 750 ($203 in our model).
Can Santa Cruz stop me from building an 800 sq ft ADU?
Not with lot coverage, floor area ratio, open space or minimum lot size limits. State law requires cities to allow at least an 800 sq ft ADU with 4 ft side and rear setbacks (Gov. Code §66321(b)(3)), provided it meets other objective standards such as height.
Do school fees apply at 800 sq ft?
Yes. School fees apply above 500 sq ft; at 800 sq ft the statewide Level 1 cap is $4,304, and many districts charge less.
Not modeled yet
What these totals leave out
- Water and sewer connection fees (the City says new detached ADUs almost always pay them).
- Traffic impact fee, which applies only in Council-designated areas.
- Whether the Parks & Recreation facilities tax applies to ADUs (high total only).
- Addressing fee (hourly) and Coastal Permit fees where they apply.
- School district's actual rate (statewide Level 1 maximum shown).
More
Keep going
Sources
Official sources
Every figure comes from these documents; each line’s quoted text is on the Santa Cruz page.
- City of Santa Cruz, Planning and Community DevelopmentDepartment Fee Schedule (effective January 1, 2026, updated 1/5/2026) (opens in new tab)
- City of Santa Cruz, Planning and Community DevelopmentAccessory Dwelling Units (ADUs) (opens in new tab)
- California State Allocation Board (Department of General Services, OPSC)State Allocation Board item: 2026 adjustment to the Level I developer fee (meeting of January 28, 2026) (opens in new tab)
- California Legislative Information (leginfo.legislature.ca.gov)Government Code, Title 7, Division 1, Chapter 13 (Accessory Dwelling Units), incl. §66311.5 (opens in new tab)
- HCD via data.ca.govHousing Element Annual Progress Report (APR) data, Table A2: ADU building permits by year (opens in new tab)