Utah County · 12,999 residents

Mapleton ADU rules

Q: What lot size does Mapleton require for an ADU?

Internal ADU: 6,000 sq ft minimum. ≥6,000 sq ft legal lot of record. Detached ADU: 11,000 sq ft minimum. ≥11,000 sq ft (Ord. 2026-09, Jun 3, 2026 — reduced from 21,780 sq ft).

Q: Does Mapleton require the owner to live on the property?

Internal ADU: Required (or family-only occupancy exempts some provisions). Detached ADU: Required.

Q: How much parking does a Mapleton ADU need?

Internal ADU: 1 designated hard-surface off-street stall in addition to primary; limits on front/street-side setback placement. Detached ADU: 1 designated off-street stall in addition to primary.

Q: What does it cost to build an ADU in Mapleton?

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.

Q: Can an HOA block an ADU in Mapleton?

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.

Mapleton: internal ADUs allowed (lot 6,000+ sq ft); detached ADUs allowed (lot 11,000+ sq ft). Owner occupancy applies.

Internal ADU (inside the home)

Generally allowed

Detached ADU (backyard building)

Generally allowed

Not yet fully verified · last reviewed September 7, 2026 See sources

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Mapleton ADU rules at a glance

Mapleton internal and detached accessory dwelling unit rules
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 legal lot of record	11,000 sq ft. ≥11,000 sq ft (Ord. 2026-09, Jun 3, 2026 — reduced from 21,780 sq ft)
Owner occupancy	Required (or family-only occupancy exempts some provisions)	Required
Parking	1 designated hard-surface off-street stall in addition to primary; limits on front/street-side setback placement	1 designated off-street stall in addition to primary
Size limits	No maximum for internal; within primary footprint	1,000 sq ft (11,000–87,119 sq ft lots); 1,200 sq ft (87,120–130,679); 1,400 sq ft (≥3 acres). Prior 40%-of-primary cap deleted by Ord. 2026-09
Height	Not yet verified — confirm with the city	Per accessory building standards §18.84.230 (height rises with lot size); <15 ft height → ≥3 ft side/rear setbacks
Setbacks	Entrance/exit on side or rear; appearance of single-family dwelling preserved	Front wall of detached structure ≥10 ft behind front wall of primary; accessory building ≤20% of rear yard; §18.84.230 standards
Zones	All residential zones except SDP-1 (Harvest Park) and R-2-B	Detached subsection does not list eligible zones explicitly — confirm with staff
Permit process	Accessory apartment permit application + fee with Community Development; no CUP/public hearing specified	Accessory apartment permit; permitted-use style administrative process

State law: detached ADUs from October 1, 2026

Mapleton 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 Mapleton 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; Mapleton makes the decision.

"Likely" above 15,000 sq ft is this site's planning band for a large recorded lot. It is not a sentence in the Mapleton 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.

Open Mapleton on the property map

Planning notes for Mapleton

Mapleton’s accessory-apartment section distinguishes internal and detached designs and addresses owner occupancy. It also includes a family-occupancy exemption, which should not be mistaken for an exemption from construction permits. We can help compare the intended occupants, lot and layout against the right part of §18.84.410.

Bring these to your review

Lot dimensions and zoning
Whether the unit is for family or unrelated tenants
Building placement, floor area and entrance sketch

The question to resolve first

Which provisions apply to your occupancy arrangement and chosen ADU type?

Sources

We link only to government sources and public meeting records. Codes change; confirm the current version with Mapleton before you apply.

Utah S.B. 284 (2026), enrolled bill
Statewide detached-ADU requirements for specified municipalities, operative October 1, 2026.
Official Mapleton website

Common Mapleton ADU questions

Can you build an ADU in Mapleton?

Mapleton: internal ADUs allowed (lot 6,000+ sq ft); detached ADUs allowed (lot 11,000+ sq ft). Owner occupancy applies. This is planning guidance, not a permit. Confirm the zone on your parcel with Mapleton.

What lot size does Mapleton require for an ADU?

Internal ADU: 6,000 sq ft minimum. ≥6,000 sq ft legal lot of record. Detached ADU: 11,000 sq ft minimum. ≥11,000 sq ft (Ord. 2026-09, Jun 3, 2026 — reduced from 21,780 sq ft).

Does Mapleton require the owner to live on the property?

Internal ADU: Required (or family-only occupancy exempts some provisions). Detached ADU: Required.

How much parking does a Mapleton ADU need?

Internal ADU: 1 designated hard-surface off-street stall in addition to primary; limits on front/street-side setback placement. Detached ADU: 1 designated off-street stall in addition to primary.

What does it cost to build an ADU in Mapleton?

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 Mapleton?

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 Mapleton 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 Mapleton lot?

Free, no obligation. We review your parcel against these rules and, if you want, introduce independent design and construction partners. Partners may pay us for referrals.

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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.