Utah County · 44,102 residents
Spanish Fork ADU rules
Spanish Fork: internal ADUs allowed (lot 6,000+ sq ft); detached ADUs allowed (lot 6,000+ sq ft). Owner occupancy applies.
Internal ADU (inside the home)
Detached ADU (backyard building)
Not yet fully verified · last reviewed September 7, 2026 See sources
Spanish Fork ADU rules at a glance
| Rule | Internal ADU (basement, attic, inside the home) | Detached ADU (backyard building) |
|---|---|---|
| Allowed? | Allowed | Allowed |
| Minimum lot | 6,000 sq ft. ≥6,000 sq ft | 6,000 sq ft. ≥6,000 sq ft (more permissive than SB 284 floor) |
| Owner occupancy | Required; temporary leave exceptions exist | Required |
| Parking | 3 off-street spaces total (2 primary + 1 internal ADU); ADU spaces may not be tandem | Pre-amendment: 4 total spaces, no tandem. Aug 2026 proposed/text amendment: if DADU <650 sq ft → 3 total (2+1); if ≥650 → 4 total (2+2), to align with Utah Code parking caps |
| Size limits | Only 1 ADU per lot; internal max not stated in guidebook summary | Detached max 1,000 sq ft |
| Zones | Most residential zones | Most residential zones |
| Permit process | Community Development application with floor/site plans; annual renewal for rentals; impact fees eliminated 2019 | Same ADU process; staff notes city already largely SB 284-compliant except parking tier for small DADUs |
State law: detached ADUs from October 1, 2026
Spanish Fork is a “specified municipality” under Utah S.B. 284. Beginning October 1, 2026, it must permit one detached ADU as a permitted use on a lot of 11,000 sq ft or more that has a detached single-family home. The city can still apply setbacks, height, design, owner-occupancy and limited parking rules, and it may allow detached ADUs on smaller lots. How the state ADU laws work.
How our property map screens Spanish Fork lots
The map colors parcels using the rules on this page and the recorded lot size. A color is a planning screen, not a permit; Spanish Fork makes the decision.
- The statewide map screen starts a new external ADU at about 11,000 sq ft. Spanish Fork's researched external minimum is 6,000 sq ft. Lots below that city minimum stay highly unlikely on the map even when they clear 11,000 sq ft.
- "Likely" above 15,000 sq ft is this site's planning band for a large recorded lot. It is not a sentence in the Spanish Fork code. Owner occupancy, parking, setbacks, zones, and HOA rules below still have to be checked.
Planned communities, PRDs and PUDs
Reviewed on September 22, 2026 against this city's research file, its published ADU page where one was found, and Utah meeting packets. No adopted sentence was confirmed that allows or bans an ADU in every PUD, PRD, PRUD, or planned community. If the assessor class or subdivision name says PUD, PRD, PRUD, planned unit development, planned residential development, planned community, resort community, or master planned community, the map keeps that lot highly unlikely regardless of size. A plat, CC&Rs, or development agreement can still prohibit an ADU where the zone allows one.
Planning notes for Spanish Fork
Spanish Fork describes ADUs within a home or in a permanent accessory structure. Its published process includes annual registration, owner occupancy and different parking requirements for internal and external units. We can help compare both layouts and prepare the registration and construction materials together, including how the secondary address is assigned.
Bring these to your review
- Site plan showing parking and building locations
- Owner-occupancy plan and proposed floor area
- Existing permit history and preferred unit type
The question to resolve first
What current zoning, parking and registration steps apply to this design and submission date?
Sources
We link only to government sources and public meeting records. Codes change; confirm the current version with Spanish Fork before you apply.
- Utah S.B. 284 (2026), enrolled bill
Statewide detached-ADU requirements for specified municipalities, operative October 1, 2026.
- Official Spanish Fork website
Common Spanish Fork ADU questions
Can you build an ADU in Spanish Fork?
Spanish Fork: internal ADUs allowed (lot 6,000+ sq ft); detached ADUs allowed (lot 6,000+ sq ft). Owner occupancy applies. This is planning guidance, not a permit. Confirm the zone on your parcel with Spanish Fork.
What lot size does Spanish Fork require for an ADU?
Internal ADU: 6,000 sq ft minimum. ≥6,000 sq ft. Detached ADU: 6,000 sq ft minimum. ≥6,000 sq ft (more permissive than SB 284 floor).
Does Spanish Fork require the owner to live on the property?
Internal ADU: Required; temporary leave exceptions exist. Detached ADU: Required.
How much parking does a Spanish Fork ADU need?
Internal ADU: 3 off-street spaces total (2 primary + 1 internal ADU); ADU spaces may not be tandem. Detached ADU: Pre-amendment: 4 total spaces, no tandem. Aug 2026 proposed/text amendment: if DADU <650 sq ft → 3 total (2+1); if ≥650 → 4 total (2+2), to align with Utah Code parking caps.
What does it cost to build an ADU in Spanish Fork?
Wasatch Front planning bands are often about $55,000–$145,000 for an internal suite, $70,000–$175,000 for a garage conversion, and $95,000–$250,000 or more for a new detached unit, before unusual site work. These are planning ranges, not bids.
Can an HOA block an ADU in Spanish Fork?
City approval does not override CC&Rs or plat notes. Read the HOA documents and your subdivision plat before you design. A private restriction can stop a unit the city would otherwise allow.
Before you design: general checks for any Utah ADU
General planning advice, not Spanish Fork code.
- Confirm the zoning district on the city zoning map. The county assessor’s “residential” class is not zoning.
- Read your HOA CC&Rs and subdivision plat notes; private restrictions can block a unit the city allows.
- Sketch existing and proposed parking. Driveway geometry and access often decide what fits.
- Ask early about sewer, water and electrical capacity; utilities can force a redesign.
- Expanding a building’s footprint usually triggers full setback and height rules.
Nearby city ADU rules
Want to know what fits on your Spanish Fork lot?
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Utah ADU Builder provides educational planning guidance. This page is not legal advice and not a permit. Population: UGRC POPLASTESTIMATE / Census-derived municipal estimates (manual fill where UGRC blank). Editorial standards.