By the Utah ADU Builders Editorial Team · Last verified: July 2026 · Scheduled review: October 1–15, 2026 (state detached-ADU law effective date).
Holladay ADU Builders: What Your Lot Allows, What It Costs, and How to Start
Holladay allows both internal and detached accessory dwelling units (ADUs) on a parcel that has a detached single-family home, in its residential zones — one ADU per lot, with a building permit and, if you rent it, a 30-day-minimum lease and an owner (or close family member) living on site. It's a common choice for housing a parent or adult child, or for a long-term rental. It's not a path to a nightly Airbnb, and it isn't automatically cheap. What you can build depends on your lot's size, setbacks, coverage, parking, utilities, and intended use — not just on whether ADUs are "allowed."
This guide covers what your lot allows, what an ADU costs here, and how to compare Holladay ADU builders before you request estimates.
An ADU (accessory dwelling unit) is a second, smaller home on the same lot as your main house — a basement apartment, an attached suite, or a standalone backyard cottage.
The short version
| Your question | The bottom line |
|---|---|
| Are internal and detached ADUs allowed in Holladay? | Yes — on a residential parcel that has a detached single-family home, one ADU per lot. |
| Is there still a half-acre minimum lot size? | No — the current code removed the former half-acre / twice-the-zone requirement for detached ADUs. (Some older city materials, including the 2023 application, still show the old rule.) |
| Can I run it as a short-term rental (Airbnb)? | No. A rented ADU in Holladay must be leased for 30 consecutive days or longer, and the owner or immediate family must live on the property. |
| What does one cost? | Broad Utah planning ranges run from roughly $60,000 for some conversions to $400,000+ for a custom detached build. Your lot, utilities, and finishes decide where you land. |
| What should I do first? | Check feasibility for your specific property before you pay for plans or pick a builder. |
What we verified
We built this page from primary sources and checked each rule against the current text, not older summaries:
- Holladay's current ADU ordinance — Holladay Municipal Code §13.14.031 (as amended by Ordinance 2024-18, adopted November 7, 2024), plus the accessory-building rules (§13.14.110), lot-coverage limits (§13.14.080), and the footprint and setback charts (Charts 13.14.101, 13.14.080B, and 13.14.032).
- Holladay's current permit process — the city's Construction Submittal Requirements page.
- Utah state law — Utah Code §10-21-303 (internal ADUs in municipalities) and §10-21-304 (detached ADUs, enacted by SB 284 in the 2026 legislative session, effective October 1, 2026).
- Cost inputs — our statewide ADU cost research, presented as planning ranges rather than Holladay-specific averages.
- A document conflict we flagged for you — some older city materials (including the 2023 ADU application) still show a repealed half-acre minimum and an older height figure; the current code does not.
What we did not do: give legal, tax, financing, architectural, or engineering advice, or guarantee any permit approval, fee, timeline, rental income, or increase in property value. Cost and timeline figures are estimates that vary by property and project.
Can you build an ADU in Holladay?
Yes — Holladay permits both internal and detached ADUs on a residential parcel that already has a detached single-family home, limited to one ADU per lot. You'll need a building permit and a certificate of occupancy, and an annual license if you rent it. Whether your project works comes down to size, setbacks, coverage, parking, utilities, and how you plan to use it. (Source: Holladay Municipal Code §13.14.031.)
Holladay's ordinance recognizes two categories:
- Internal ADU (IADU) — a unit created inside your existing home or within its existing footprint. Think of a basement apartment or a converted level of the house. Internal units must add code-compliant egress (escape) windows where required.
- External / detached ADU (EADU) — a separate structure, or a converted detached garage. These carry additional size, setback, height, coverage, and design rules covered below.
(Holladay's single-family residential zones — R-1-4 through R-1-87 — allow ADUs under these standards.)
A quick first-pass eligibility read
| Your situation | First-pass read | Why |
|---|---|---|
| Detached single-family home; a family member will live in the ADU | Plausible candidate | Still subject to size, setback, coverage, parking, utility, and permit review |
| Detached single-family home; a 30-day-plus tenant; owner lives on site | Plausible candidate | Annual rental license applies |
| You want nightly / short-term (Airbnb) rental | Doesn't fit as a standard ADU | Holladay requires a 30-consecutive-day minimum for an ADU rental |
| You want to rent both units and live elsewhere | Doesn't fit | The owner or immediate family must occupy one of the units (limited temporary-absence exception) |
| The property has a failing septic system | Doesn't fit yet | Expressly prohibited until resolved |
| You're not sure the property is actually inside Holladay | Verify first | Mailing addresses can say "Holladay" while the parcel is in Millcreek, Cottonwood Heights, or unincorporated Salt Lake County — the rules follow the actual jurisdiction |
Watch out: the city's own paperwork disagrees with itself
Here's a subtle but important point that even some of the city's own materials get wrong. Holladay's current code (updated in late 2024) removed the old requirement that a detached ADU sit on a lot of at least a half-acre (or twice the zone's minimum lot size). Today, a detached ADU is allowed on a qualifying residential parcel with a detached single-family home, with no separate minimum-lot-size gate — though the footprint and coverage charts below still control how large the building can be.
But older city materials — including the 2023 ADU application still linked from the website, and legacy text lower on the city's ADU page — continue to show that repealed half-acre rule and an older blanket height figure. If you rely on the old form, you may talk yourself out of a project that's now allowed, or design to the wrong numbers. Use the current code, and confirm the current submittal packet before you file.
What the new state law changes (and doesn't) for Holladay
Utah passed a statewide detached-ADU law — Utah Code §10-21-304, enacted by SB 284 — that takes effect October 1, 2026. Beginning on that date, it requires "specified" cities (a category that includes Holladay) to permit a detached ADU on any lot 11,000 square feet or larger that holds a single-family home, and it lets cities allow them on smaller lots too. It also bars those cities from requiring a conditional use permit for a detached ADU in a residential zone as a blanket requirement (though case-specific ones may still apply).
For Holladay, the practical effect is limited — in a good way. Holladay already permits detached ADUs on qualifying lots with no minimum lot size, so it's already more generous than the state's floor. The state law mainly acts as a backstop that locks in detached-ADU rights and parking limits for specified cities.
One detail to watch: Holladay's current code requires a conditional use permit only in a narrow case — converting an existing accessory building whose footprint exceeds the chart. The October 2026 state law doesn't override that case-specific CUP requirement.
Which type of ADU (and builder) fits your goal?
The right builder depends on the project. Converting existing space — a basement or a garage — is usually the lower-cost path when the existing space is sound, because you're not pouring a new foundation. A detached backyard unit costs and takes more but offers the most privacy and flexibility. Match the project type to your goal first, then find a builder who does that specific work in the Salt Lake County area.
A quick term you'll see from builders: an "attached ADU" in marketing usually maps to Holladay's internal ADU category if it's within the home's footprint. Have the builder confirm which local category your design falls under, because the rules differ.
| Project path | Builder you need | Usually best for | Holladay friction to resolve first |
|---|---|---|---|
| Basement / internal conversion | Remodeler or design-build contractor experienced with egress, plumbing, and fire/life-safety | Lower cost, family housing, tight yards | Egress windows, ceiling height, separate entrance, utility access, parking |
| Attached garage conversion | Remodeler experienced with garage-to-living-space | Reusing an existing shell | Replacing lost parking, slab, insulation, HVAC, plumbing |
| Detached garage conversion | Design-build contractor comfortable with detached (EADU) rules | Privacy while reusing a structure | Setbacks, footprint chart, height, and a conditional use permit if the footprint exceeds the chart |
| New detached / site-built ADU | General contractor or design-build team experienced in small new homes, foundations, and site work | Maximum privacy and separation | Footprint chart, lot coverage, graduated height, setbacks, utilities, parking |
| Prefab / modular ADU | Manufacturer plus local site, foundation, utility, permit, and installation capability | Repeatable plans or off-site fabrication | Package price vs. installed cost; transport and crane access; local code compliance |
| Shipping-container concept | Not a standard path in Holladay | — | Holladay prohibits shipping containers, semitrailers, boxcars, PODS, and similar structures on residential lots |
Our practical view: when internal beats detached
An internal conversion is usually the lower-risk choice when your home already has usable space, utilities are close by, and your yard or budget is tight. A detached unit is usually worth the extra cost when privacy, accessibility, or true separation matters enough to justify a new foundation, a utility run, and site work.
- Lowest likely cost? Start with a basement/internal conversion — if the existing space is sound.
- Housing a parent who needs single-level, accessible living? A detached unit (or a well-designed main-floor internal unit) often fits better.
- Have a detached garage already? Check conversion feasibility — but don't assume it's cheapest, because parking replacement and code upgrades can erase the savings.
Two cautions worth stating plainly:
Prefab is not automatically cheaper: a factory price may not include your foundation, utility connections, transport, crane access, permitting, and site prep — so never compare a package price to an installed site-built bid.
And a garage conversion is not automatically simplest: an unsuitable slab, missing plumbing, poor insulation, moisture issues, or lost parking can add up fast.
How big can a detached ADU be in Holladay?
A detached ADU must be at least 200 square feet. The maximum footprint and the required distance from your property lines both scale with your lot size, and lot-coverage limits can further cap what fits. The chart below is the starting point — but existing sheds, garages, and other structures count against your total, so your buildable area may be smaller than the maximum.
Holladay doesn't set a minimum lot size for a detached ADU, but it does control footprint (the ground area the building covers) and setbacks (how far a structure must sit from property lines).
Chart 13.14.101 — Accessory-building footprint and setback by lot size
This chart governs the total footprint of all accessory buildings on the lot (not the ADU alone) and the minimum distance from side and rear property lines.
| Lot size (sq ft) | Max total accessory footprint (sq ft) | No closer than (ft) |
|---|---|---|
| Less than 8,000 | 800 | 3 |
| 8,001 – 14,600 | 850 | 4 |
| 14,601 – 21,200 | 900 | 5 |
| 21,201 – 27,800 | 950 | 6 |
| 27,801 – 34,400 | 1,000 | 7 |
| 34,401 – 41,000 | 1,050 | 8 |
| 41,001 – 47,600 | 1,100 | 9 |
| 47,601 – 54,200 | 1,150 | 10 |
| 54,201 – 60,800 | 1,200 | 11 |
| 60,801 – 67,400 | 1,250 | 12 |
| 67,401 – 74,000 | 1,300 | 13 |
| 74,001 – 80,600 | 1,350 | 14 |
| More than 80,600 | 1,400 | 15 |
Source: Holladay Municipal Code §13.14.110, Chart 13.14.101. If your lot size lands exactly on a bracket edge (for example, exactly 8,000 or 10,000 square feet), treat the result as needing property-specific confirmation rather than assuming a row.
- It's shared. An existing detached garage, shed, gazebo, or pool house eats into your total accessory footprint. Measure what's already there.
- Coverage can cut it further. See the lot-coverage limits below — your ADU has to fit under both the footprint chart and the coverage caps.
- Setbacks and easements still apply. No accessory building may sit in a front setback, in a required side setback that faces a street, or in a utility or other easement without written consent.
Chart 13.14.080B — Lot coverage
Everything you build has to stay under your lot's coverage limits — one for all structures, and a separate (higher) one for total impervious surface like driveways and patios.
| Lot size (sq ft) | Max coverage — all structures | Max impervious coverage |
|---|---|---|
| Less than 10,000 | 35% | 40% |
| 10,001 – 15,000 | 31% | 36% |
| 15,001 – 20,000 | 28% | 33% |
| 20,001 – 30,000 | 25% | 30% |
| 30,001 – 40,000 | 24% | 29% |
| 40,001 – 50,000 | 23% | 28% |
| 50,001 – 60,000 | 22% | 27% |
| 60,001 – 70,000 | 21% | 26% |
| Above 70,000 | 20% | 25% |
Source: Holladay Municipal Code §13.14.080, Chart 13.14.080B. Holladay allows a limited impervious-coverage bonus (up to 10%) for measures like water-wise landscaping, permeable pavers, or planting trees — but that bonus never raises the maximum structure coverage.
How tall can it be?
A detached ADU can be up to 25 feet above existing grade. Two caveats: if any part sits in a required setback, it may be limited to 20 feet, and a "graduated height" rule (which slopes the allowable height inward as you get close to a property line) can force a lower wall, a redesigned roof, or more setback near the edges. So 25 feet is a ceiling, not a guarantee at every point on the lot.
The code allows documented setback reductions
Setback reductions aren't automatic, but if your ideal footprint is a little tight against the setback, Holladay's code lets you reduce it in exchange for design features that protect neighbors. You file a signed agreement describing the treatment and the resulting distance (and you can't reduce below the chart's "no closer than" minimum).
| Design feature | Setback reduction |
|---|---|
| No lights on sides facing neighboring homes | 10% |
| 8-ft fence agreement or 6-ft masonry wall | 30% |
| 8-ft masonry wall | 50% |
| Single-story structure with a max 10-ft wall height | 50% |
| Immediately adjacent to an existing accessory building next door | 80% |
| Below-grade living space only | 100% |
| Upgraded, certified energy-efficient construction designed to reduce sound | 100% |
| Coordinating with your neighbor to build adjacent ADUs | 100% |
| Immediately adjacent to a non-residential use | 100% |
| Other buffering (extra landscaping, screening/acoustic walls, window treatments, etc.) | 10% per item |
Source: Holladay Municipal Code, Chart 13.14.032.
Detached units also carry a few privacy-oriented design rules: dark-sky-compliant exterior lighting (warm, full-cutoff fixtures), doors and windows that don't open into a required setback, and landscaped setback buffers. And the city notes that adding a second driveway for ADU access requires a circular-driveway connection with 35 feet between the entrances.
Converting an existing detached building? That's allowed, including some legally nonconforming structures — but if the existing footprint exceeds the chart, you'll need a conditional use permit, and you generally can't add a second level above 12 feet if the building doesn't meet accessory-structure setbacks.
What rental, parking, owner-occupancy, and utility rules apply in Holladay?
Beyond size, four rules quietly make or break a Holladay ADU: how you can rent it, who has to live there, where the parking goes, and how utilities are handled. These are the ones that can catch homeowners late in the process.
| Rule | What it means for you | What no one can promise you |
|---|---|---|
| 30-day minimum rental | Plan for long-term tenants | Airbnb or nightly-rental income |
| Owner occupancy | The owner or immediate family must live in the main home or the ADU | Renting both units while you live elsewhere |
| Occupancy limit | One household only | Housing an unlimited number of unrelated tenants |
| Annual license if rented | Renting is an ongoing compliance step, not one-and-done | A permanent, no-maintenance approval |
| One extra on-site parking stall | You need a parking spot beyond your home's normal requirement | That street parking will satisfy it |
| Replace displaced parking | Converting a garage may require adding parking elsewhere | That a garage conversion is automatically cheapest |
| Bedroom-based parking (for units outside the existing footprint) | Larger units can require more stalls | A single universal parking answer |
| Same address + "Unit B" | It's not a separate, separately-addressed lot | A separate legal parcel you can sell off |
| No separate utility meters | The ADU shares the main home's meters; tenants must have access to shutoffs, the panel, and HVAC | Independent city utility accounts |
| No failing septic | System condition can be a threshold issue | Approval before the system is confirmed sound |
Owner occupancy, defined: the owner (listed on the county tax rolls) — or an immediate family member: spouse, parent, child, sibling, grandparent, or grandchild — must live full-time in the main house or the ADU. There's a limited exception for a genuine temporary absence of up to three years (military, a job assignment, a sabbatical, or voluntary service) if you lived there before leaving and resume living there when you return.
Occupancy, defined: the ADU may house a single household — one person living alone, any number of related family members living together, or up to four unrelated people living together as a single household. That limit matters before you design bedroom count.
A note on the new state parking limits: when §10-21-304 takes effect on October 1, 2026, cities can't require more than two on-site spaces for a detached ADU of 650 square feet or larger (or more than one space below 650 square feet). If your project is larger, that state cap may limit Holladay's bedroom-based parking requirement — a detail worth confirming for your specific plan.
What does a Holladay ADU cost?
There's no honest single "Holladay average" — costs swing widely with type, size, site access, utility runs, foundation work, and finishes. As a planning frame, converting existing space sits at the low end and a finished detached build at the high end. Treat every number below as an estimate, then get a lot-specific figure before you budget.
| ADU path | Broad Utah planning range | Biggest cost driver |
|---|---|---|
| Basement / internal conversion | $60,000 – $150,000+ | Egress, layout, plumbing, electrical, fire separation |
| Garage conversion | $60,000 – $175,000+ | Slab condition, insulation, utilities, HVAC, replacement parking |
| Attached / connected addition | $150,000 – $275,000+ | Foundation, structural tie-in, roof, utility extension |
| Detached / site-built ADU | $200,000 – $400,000+ | Foundation, utilities, site work, access, setbacks |
| Prefab / modular (installed) | $150,000 – $300,000+ | Package exclusions, transport, crane, foundation, utilities |
These are statewide planning ranges from our Utah ADU cost guide and cost methodology — not Holladay-specific averages, and not quotes.
What moves your number the most: whether you're reusing an existing shell or building new; the distance and capacity of water, sewer, and electrical; sewer depth and slope; whether your electrical panel needs an upgrade; foundation and grading; backyard access for equipment; trees and hardscape to protect or remove; design and engineering; finish level; and permit, zoning-review, and impact fees (one-time fees a city charges new development to help pay for infrastructure).
One genuine cost break worth knowing: under Utah law, construction of an internal ADU within an existing primary dwelling may not be charged an impact fee. Detached units and additions can still incur them. Note that in Holladay the building-permit fee is based on your project's construction valuation, while zoning-review and impact fees may apply separately under the city's fee schedule. (Source: Holladay Construction Submittal Requirements.)
How long do permits and construction take?
Holladay aims to complete a first plan review within seven business days after your paid application is processed and accepted — but that's the first review, not the permit. Corrections, additional reviews, design and engineering time, and construction mean the full idea-to-move-in timeline can run months, and it's specific to your property and scope.
| Phase | What happens | Timing |
|---|---|---|
| Property screening | Confirm jurisdiction, use, lot, parking, utilities, site constraints | No fixed duration |
| Design & engineering | Prepare property-specific plans | Scope-dependent |
| Application | Submit online with plans attached | Online applications only; plans required |
| Initial processing | Pay initial fees; staff route to reviewers | ~1–2 business days after payment |
| First plan review | Zoning and building review | City goal of ~7 business days; longer during high volume |
| Corrections | Revise and resubmit as needed | Each cycle adds time |
| Special review | Geologic or third-party review, if applicable | Additional time; Utah law allows up to 14 business days per review |
| Permit issuance | Plans compliant, final fees paid | No fixed duration |
| Construction & inspections | Build, inspect, and close out with a certificate of occupancy | Contractor- and project-specific |
Source: City of Holladay Construction Submittal Requirements; Utah Code review-time provisions.
Don't read "seven business days" as a seven-day permit. It's the target for the first look; a project may move through review, one or more correction cycles, re-review, final fees, and only then issuance.
And don't assume a small unit skips permitting. Holladay exempts some one-story detached accessory buildings under 200 square feet from a permit — but an ADU must be at least 200 square feet and always needs a building permit and a certificate of occupancy.
What to have ready before you ask builders for estimates
A builder can't give you a meaningful, comparable estimate from a square-footage wish alone. Gather the property facts that drive Holladay eligibility, the building envelope, utilities, parking, access, and intended use — then estimates line up on the same basis.
Property
- Address, confirmed jurisdiction, parcel number, recorded lot size, and zoning
- Known easements, and any HOA or recorded covenant that might restrict building (confirm what those documents actually say — don't assume)
Existing conditions
- Approximate footprint of the main home and every existing accessory structure (garage, shed, etc.)
- Current parking count and dimensions
- Photos of the yard, driveway, garage, basement, utility areas, and the access route
- Any known unpermitted work, septic condition, slope, drainage, flood, or geologic-hazard concerns
- Significant trees and hardscape; width available for equipment, a modular delivery, or a crane
The project
- Internal, garage-conversion, attached, detached, or prefab concept
- Approximate size and bedroom count
- Family housing vs. 30-day-plus rental; any accessibility needs; desired finish level
- Budget band, and a target timeframe (understanding it can't be guaranteed)
Utilities
- Approximate locations of water, sewer, gas, and electrical; panel size if known; sewer route and depth if known
- Whether tenant access to utility controls can be preserved in your layout
How to compare Holladay ADU builders
Don't choose on headline price. Verify the contractor's current Utah license, confirm they've done your specific project type, and compare exactly who is responsible for design, engineering, permits, corrections, site work, utilities, allowances, change orders, inspections, and closeout. Two "estimates" that look far apart often just include different scope.
Use this scorecard to put bids on equal footing:
| Check | Ask for | Why it matters |
|---|---|---|
| Legal identity | Exact business entity name | Needed to verify license, insurance, and the contract |
| Utah license | License number, classification, current status | Confirms the public record for the contracting entity |
| Insurance | Current certificate naming that entity | Confirms coverage exists, its limits, and the named entity — though a certificate isn't a guarantee any specific claim is covered |
| Right experience | Examples of your project type (internal, garage, attached, or detached) | General remodeling isn't the same as detached-ADU work |
| Holladay familiarity | Recent local examples applying Holladay's rules | Avoids builders who apply another city's standards by mistake |
| Design & engineering | Who produces drawings and structural/civil work | A source of scope gaps and price swings |
| Permits | Who submits, handles corrections, and pays which fees | 'We handle permits' is too vague |
| Utilities & site work | Trenching, connections, panel upgrades, grading, access, restoration | A common reason cheap bids balloon later |
| Parking | Whether required or replacement parking is included | A real Holladay requirement |
| Allowances & change orders | Written amounts and a change-order process | Prevents misleading low bids and budget drift |
| Schedule & warranty | Assumptions, exclusions, and written warranty | More useful than a promised finish date |
Verify the license yourself. Most Utah contractors must be licensed through the Utah Division of Professional Licensing (DOPL), which offers a free public license lookup by name or license number. Confirm the entity's license status and ask for current proof of insurance before you sign anything. DOPL also publishes an optional generic residential construction agreement and change-order forms you can review as a starting point — helpful, but not legal advice.
- Quoting Salt Lake City's rules as if they were Holladay's
- Guaranteeing permit approval
- Quoting before asking about your lot, utilities, parking, or intended use
- Refusing to share a legal entity name or license number
- Presenting a prefab package price as the installed total
- Omitting site work or utilities
- Large up-front payments without matching deliverables
- Promising rental income or a specific increase in your property's value
When a Holladay ADU might not be worth it
An ADU isn't automatically a smart project just because Utah and Holladay have become more ADU-friendly. The right project depends on your lot, your city's rules, your utilities, your budget, and how you'll actually use it. A feasibility check is the cheapest way to find out before you spend on plans.
Reconsider — or expect a harder, costlier project — if:
- You're counting on short-term / nightly rental income (Holladay requires 30-day-minimum leases).
- You won't live on the property and no immediate family member will (owner occupancy applies).
- Existing structures already use up your footprint or coverage allowance.
- Your utilities are far away or at capacity, or your electrical panel needs a major upgrade.
- Access is tight — a detached build or a modular delivery may be impractical.
- An easement, slope, tree, or hazard cuts across the buildable area.
- The budget only pencils out on optimistic rent or appreciation assumptions.
None of these means "never." Several point toward a lower-risk path — often an internal conversion instead of a detached build. That's exactly the kind of call a feasibility review is for. See also: Is an ADU worth it in Utah?
The safest next step
Verify the property and your intended use, pick the most plausible ADU type, screen your lot against Holladay's size and coverage rules, build a realistic all-in cost range, and only then request comparable builder estimates. Doing it in that order keeps you from paying for plans — or hiring a builder — around a concept that has to be redesigned later.
Confirm your property and that it's actually in Holladay.
Define how you'll use the unit and who will live there.
Screen internal vs. garage vs. detached against the rules above.
Build a preliminary cost range that includes site work, utilities, design, permits, and contingency.
Request estimates from builders whose experience matches your chosen path.
Frequently asked questions
Sources we reviewed
- Holladay Municipal Code — §13.14.031 (Accessory Dwelling Units, as amended by Ord. 2024-18); §13.14.110 (Accessory Buildings; Chart 13.14.101); §13.14.080 (Lot Coverage; Chart 13.14.080B); Chart 13.14.032 (setback reductions). (codelibrary.amlegal.com/codes/holladayut)
- City of Holladay — Construction Submittal Requirements; Housing & Community Resources ADU information. (holladayut.gov)
- Utah Code — §10-21-303 (internal ADUs in municipalities); §10-21-304 (detached ADUs), enacted by SB 284, 2026 General Session (effective October 1, 2026); §11-36a-202 (impact-fee limits, including the internal-ADU exemption). (le.utah.gov)
- Utah Division of Professional Licensing (DOPL) — contractor licensing and public license lookup. (dopl.utah.gov)
- Utah ADU Builders — statewide ADU cost research (used for planning ranges). See our Utah ADU cost guide and cost methodology.
Rules and fees change. Holladay's ADU ordinance and the state detached-ADU law are both current as of the last-verified date above; local verification for your specific property is required before you design, budget, or build.
Related resources
- Can I build an ADU in Utah? Statewide guide · Utah ADU permits guide · Salt Lake County ADU guide
- Utah ADU cost guide · Cost methodology · ADU financing in Utah
- Detached ADU guide · Basement ADU guide · Garage conversion guide · Prefab ADU Utah
- ADU rental income in Utah · Is an ADU worth it in Utah?
- Nearby jurisdictions: Millcreek · Cottonwood Heights · Murray · Midvale · South Salt Lake · Draper