By the Utah ADU Builders Editorial Team · Last verified: July 2026
Murray ADU Builders: Verified Rules, Costs, and What Your Lot Allows
In Murray, you can't legally build an ADU yourself — the city requires a licensed contractor and a building permit for every one. An ADU (accessory dwelling unit) is a second, independent home on a single-family lot. Basement and attached ADUs are allowed on single-family lots with no ADU-specific size cap. A detached backyard unit needs a lot of at least 10,000 square feet and can't exceed 1,000 square feet or 40% of your home's floor area. This path fits long-term rentals and family housing — not short-term-rental investors or small-lot detached dreams. Costs and timelines vary widely by type and site.
Check your Murray property's ADU feasibility →Free property check — no obligation
About this page. Utah ADU Builders is an independent Utah ADU planning, feasibility, and builder-matching resource. We are not Murray City, a permit office, a law firm, a lender, an architect, an engineer, or a licensed contractor. We may receive compensation when homeowners request an estimate or are connected with a local professional — but that compensation does not change how we explain Murray's rules, cost ranges, feasibility factors, or permitting risks. Our practical view: shopping for Murray ADU builders before you've confirmed your lot and plan will actually work is how homeowners waste money on design and estimates. This page is built to fix that.
What we verified for this page
- Murray's ADU rules — lot size, unit size, setbacks, height, parking, owner occupancy, rental limits, and the licensed-contractor requirement — against Murray City Code Chapter 17.78 (§§17.78.040–17.78.100) and Murray City's official ADU page.
- The affidavit and rental-license steps — against Chapter 17.78 (§§17.78.060 and .100).
- Utah's internal-ADU statute and impact-fee rule — against Utah Code §10-21-303 and §11-36a-202 (via the Utah Department of Commerce).
- The 2026 detached-ADU law (S.B. 284) — against the enrolled bill and Utah Code Title 10, Chapter 21.
- HOA limits on internal ADUs — against Utah Code §57-8a-209 and §57-8a-218 (Community Association Act).
- Cost and timeline figures — are our own Utah planning estimates, clearly labeled — not Murray-specific bid averages or quotes.
Sources are listed at the bottom of the page.
Murray ADU rules at a glance
Murray allows one ADU per lot in any zone that permits a single-family home — but the standards split sharply by type. Attached and basement ADUs face no size cap; a detached (standalone) unit carries a 10,000-square-foot lot minimum and a 1,000-square-foot ceiling. Three rules catch homeowners off guard: you can't build it yourself, you must record an affidavit before the city even accepts your application, and a detached unit needs four total off-street parking spaces.
A "setback" below means the minimum distance a structure must sit from your property line. "Owner occupancy" means you (the owner) must live in either the main home or the ADU as your primary residence — this isn't an absentee-landlord product.
| Rule | Basement / internal / attached ADU | Detached ADU (standalone backyard unit) |
|---|---|---|
| How many allowed | One ADU per lot | One ADU per lot |
| Where allowed | Any zone that permits a single-family home | Same |
| Maximum size | No ADU-specific floor-area cap (still limited by your zone's lot-coverage and setback rules) | Less than 40% of your main home's floor area and no more than 1,000 sq ft |
| Bedrooms | Set by size and code | No more than 2 bedrooms |
| Minimum lot size | No detached-style minimum | At least 10,000 sq ft |
| Height / stories | Governed by your underlying zone | One story, max 20 ft (or your main home's height, whichever is less) |
| Setbacks | Additions follow your zone's standards | The same setbacks your zone requires for the main house; never in the front yard or corner-lot side yard |
| Exterior | Must keep the look of a single-family home | Color and materials must be compatible with the main house |
| Parking | 1 extra off-street space (3 total) | 2 extra off-street spaces (4 total) |
| Separate utility meter | Not allowed | Not allowed |
| Separate entrance | Side or rear only — never facing the front | Side or rear only — never on the front or corner-lot side yard |
| Owner occupancy | Required; you can't collect rent on the unit you live in | Required; you can't collect rent on the unit you live in |
| Short-term rental (under 30 days) | Not allowed | Not allowed |
| Long-term rental (30+ days) | Allowed with a Murray rental business license | Allowed with a Murray rental business license |
| Who can build it | Licensed contractor only — no owner-builds | Licensed contractor only — no owner-builds |
| Recorded affidavit | Required before your application is accepted | Required before your application is accepted |
Source: Murray City Code Chapter 17.78 (§§17.78.040–.100) and Murray City's ADU regulations page. Murray also publishes a plain-language summary that lists a few detached figures differently (for example, a 50% size figure and three parking spaces). The codified ordinance is the controlling authority — and the city's summary directs readers to it — so where they differ, and because Murray is actively updating its rules, confirm the binding standard for your specific lot before you design or budget.
The three rules people don't see coming
- You can't be your own builder. Murray does not permit owner-building of ADUs. Every ADU needs a licensed contractor and a building permit through the Murray City Building Division. That removes the "I'll save money doing it myself" option some homeowners count on.
- The affidavit comes first. Before Murray accepts your application, you complete an affidavit stating you'll live in the main home or the ADU, and once the ADU is approved it's recorded against the property so future buyers are on notice. Unprepared applicants stall here.
- Parking, and no separate meter. A detached ADU adds two required off-street spaces, for four total on the property (attached ADUs need three total). And Murray prohibits a separate utility meter for the ADU — worth knowing before you design, because it affects how the unit is serviced and billed.
Does your Murray lot pass? A quick self-check
Five questions sort most projects in a couple of minutes. The lot-size question is the fork in the road: clear 10,000 square feet and a detached unit is on the table; fall short and detached is out — but a basement or attached path may still be worth exploring. Run through these before you spend a dollar on plans.
- Lot size. Is your recorded lot at least 10,000 sq ft? Check your county parcel record, not your memory. If yes, detached is possible. If no, focus on internal or attached.
- Parking. Can you fit the required off-street spaces — four total for a detached unit, three total for an attached one — without blocking the main home's parking?
- Setbacks (detached only). Is there room in the rear/side yard for a unit that meets your zone's primary-residence setbacks and stays out of the front yard and corner-lot side yard entirely?
- Occupancy. Will you live in the main home or the ADU? If you plan to rent both and live elsewhere, this plan doesn't work in Murray.
- Rental goal. Long-term (30+ days) is allowed with a license. Short-term/Airbnb is not — full stop.
How to read your answers: Mostly "yes" means your idea is likely worth a detailed feasibility review. A mix means it may fit with design changes or a survey. A "no" on lot size, occupancy, or short-term rental means the detached or Airbnb version is a low-likelihood path under current Murray rules — though a different ADU type may still merit screening. A self-check can flag obvious conflicts; it can't verify boundaries, easements, structure, or utility capacity, and it never means "approved."
Find out what your lot can actually support before spending on plans.
See what your Murray lot can support — start a free property check →Which type of ADU makes sense in Murray?
The right type depends on your goal and your lot. Want long-term rental income on a typical lot? A basement or internal ADU is usually the lowest-cost path. Housing a parent with real privacy? Detached — if your lot clears 10,000 sq ft. Reusing what you already have? A garage conversion, when the structure cooperates.
The figures below are our Utah planning estimates (last checked July 2026), not Murray bid averages, appraisals, or quotes. Where a project lands depends on your site, existing structure, utility distance, design, and finish level. See our Utah ADU cost methodology for how we build these ranges.
| ADU type | Often best for | Key Murray feasibility gate | Utah planning cost | Rough timeline |
|---|---|---|---|---|
| Basement / internal | Lower-cost family space or rental | Egress, ceiling height, fire separation, a separate side/rear entrance, parking | $60k–$150k+ | 3–5 months |
| Garage conversion | Reusing an existing structure | A detached garage must meet the primary-residence setbacks; parking may need replacing | $60k–$175k+ | 3–6 months |
| Attached addition | More space, no separate building | Your zone's lot coverage and setbacks; structural tie-in | $150k–$275k+ | 6–9 months |
| Detached backyard unit | Privacy, separate family housing | 10,000 sq ft lot + 40%/1,000 sq ft size cap, 4 total parking, zone setbacks | $200k–$400k+ | 8–14 months |
| Prefab / modular | A more standardized build | Same land-use, foundation, utility, permit, and delivery-access rules | $150k–$300k+ installed | 5–8 months |
"Egress" = a code-required exit, like a bedroom window big enough to climb out of. "Prefab" = a unit built largely off-site, then set on a foundation on your lot. Timelines are planning estimates from feasibility to final inspection — not a Murray review guarantee.
Basement / internal ADU
Consider this first when usable space already exists and you want the lowest practical construction cost. The catch: an unfinished basement is not an easy ADU by default. Egress windows, ceiling height, fire and sound separation, a compliant side or rear entrance, and the distance to existing plumbing all drive the number. More on basement and internal ADUs →
Garage conversion
Only cheap when the slab, insulation, setbacks, parking, and utilities all cooperate. In Murray, converting an existing detached garage means that building has to meet the setbacks required for the primary residence in your zone — an old garage sitting near the property line usually can't be converted as-is. More on garage conversions →
Attached addition
This avoids the 10,000-square-foot detached rule, but it's still bound by your zone's lot coverage and setbacks plus the structural work of tying into your existing home. Murray listing "no ADU-specific size cap" for attached units is not the same as "build any size you want." More on attached and in-law suites →
Detached backyard unit
Choose this for privacy and separation — not because it's the cheapest path (it's usually the most expensive). Beyond the lot minimum, plan around the under-40%/1,000-square-foot size cap, the two-bedroom limit, exterior materials that match your main home, the one-story/20-foot height limit, four total parking spaces, easements, site access, a new foundation, and utility routing. More on detached ADUs →
Prefab / modular
Prefab can simplify part of the build, but it is not a shortcut around Murray zoning, a foundation, local code, utility hookups, delivery access, inspections, or permit approval. More on prefab ADUs in Utah →
How much does an ADU cost in Murray?
There's no well-documented "average Murray ADU price," so treat any single number with suspicion. For planning, current Utah ranges start around $60,000 for a straightforward internal conversion and can exceed $400,000 for a custom detached build. Your lot, existing structure, utility path, design, and finish level decide where you land — see the Utah ADU cost guide for the full breakdown.
What moves a Murray estimate
- Whether you're reusing an existing legal structure (internal/garage) or building new (detached).
- Distance to sewer, water, and power and whether your electrical panel has capacity for a second unit. Murray provides power, water, and sewer in many parts of the city — with Murray City Power as the municipal electric utility — but other providers serve areas without city infrastructure, so confirm the actual providers and available capacity for your address.
- Site access for excavation and materials, plus grading, drainage, and soil conditions on a detached build.
- The licensed-contractor requirement which sets a professional-labor floor (no owner-build savings), parking and setback work, structural engineering, and finish level.
Keep in mind the 1,000-square-foot detached cap limits floor area, not total cost: a small unit on a difficult site can cost more than a larger one on an easy site.
On fees: Murray charges a small, non-refundable planning application fee for an ADU, and separate building-permit, plan-review, inspection, and utility fees are calculated from your specific project and Murray's current fee schedule — which is why we don't publish a single "all-in permit total." One state-law point worth knowing: construction of an internal ADU inside your existing home is exempt from impact fees under Utah Code §11-36a-202. An "impact fee" is a one-time charge cities levy on new development to fund infrastructure. That exemption does not remove permit, plan-review, inspection, or utility charges, and it does not automatically apply to a detached build.
Thinking about how to pay for it? See how homeowners finance an ADU in Utah and our honest take on whether an ADU is worth it.
The Murray ADU permit process, step by step
A Murray ADU moves through a predictable sequence — and the affidavit step is the one that trips people up. Here's the path from idea to finished unit:
- Confirm feasibility and zoning. Verify your property is actually inside Murray City, sits in a zone that allows single-family homes, and can physically support your chosen ADU type.
- Complete and record the affidavit. Sign the owner-occupancy affidavit; once the ADU is approved, it's recorded against the property so a future buyer is aware of the ADU rules.
- Submit your ADU application to Murray's Planning Division with a scaled site plan, floor plans, and supporting documents.
- Planning review. For a complete application, Murray's planning review runs in a matter of weeks rather than months; incomplete submissions or requested corrections delay the start of that window.
- Building permit and code review. A building permit must be obtained (define in your contractor's written scope who prepares and submits it), and the plans are checked against current building, plumbing, mechanical, electrical, and life-safety codes.
- Construction and inspections. Permitted work proceeds with required inspections, and a certificate of occupancy follows.
- Rental business license (only if you'll rent either unit long-term).
That planning-review window is just one stage — not total design, permitting, and construction time. Budget for the full sequence. (Source: Murray City Code Chapter 17.78 and Murray City's ADU application materials.)
Can you rent out a Murray ADU?
Long-term renting is allowed; short-term is not. You must live in one of the two units and you can't collect rent on the one you occupy — but the other unit can be rented for stays of 30 days or longer with a residential rental business license from Murray. Renting either unit for stays under 30 days — Airbnb, VRBO, nightly stays — is prohibited, and the affidavit you record is tied to these rules. Because owner occupancy is required, this is a long-term-tenant or family-housing product, not an absentee investment. Rental income varies with the unit, location, and market and is never guaranteed. (Source: Murray City Code §§17.78.040–.100.) More on ADU rental income in Utah →
Did Utah's 2026 law (S.B. 284) change Murray's rules?
Here's the part that's easy to get wrong. Utah's new detached-ADU provision (Utah Code §10-21-304), which takes effect October 1, 2026, requires certain cities to allow a detached ADU as a permitted use on qualifying lots of 11,000 square feet or larger, while letting cities be more permissive and keep their own standards for size, setbacks, height, parking, and rentals.
The Murray-specific truth: Murray already allows detached ADUs on 10,000-square-foot lots — below the state's 11,000-square-foot threshold. Because cities may permit smaller lots, the new law doesn't require Murray to raise its 10,000-foot minimum. But the statute reaches beyond lot size — it also governs permitted-use treatment, accessory-structure conversions, parking, and which restrictions a city may impose — so it may still shape how Murray administers detached ADUs. Treat Murray's current code as controlling, and re-check it before and after the October 1, 2026 effective date, because ordinances across Utah are being updated right now. For the bigger statewide picture, see Can I build an ADU in Utah? and the Salt Lake County ADU guide.
How to compare Murray ADU builders (and why you're required to hire one)
Because Murray bans owner-built ADUs, choosing your contractor is the project decision. The right builder has pulled Murray permits before, has designed within the 1,000-square-foot, one-story, two-bedroom detached envelope, and has priced work involving Murray's municipal utilities. Here's how to compare candidates without comparing apples to oranges.
Verify the business first (your own due diligence)
Confirm the exact legal business name and an active Utah contractor license with the appropriate classification. You can check license status and any public disciplinary record through the Utah Division of Professional Licensing (DOPL). Ask for a current insurance certificate and confirm who will actually sign your contract and supervise the work.
Look for relevant experience
Permitted ADUs, detached residential builds, basement conversions with kitchens and egress, garage conversions, and utility trenching. A builder doesn't need to have built the identical unit in Murray, but the experience should be genuinely comparable.
Normalize the scope before you compare prices
Two ADU bids are only comparable when they cover the same work. Before you look at totals, make sure each proposal spells out:
- Design/drafting, survey/site plan, and structural engineering
- Permit preparation and which city fees are included (or an allowance)
- Utility connections, excavation, and foundation
- Electrical service/panel work, HVAC, and plumbing
- Interior finish allowances and appliances
- Parking and site restoration
- Contingency, change-order markup, warranty, and explicit exclusions
- Estimated start date and duration
Red flags
Promising permit approval, calling permits optional, encouraging an owner-builder approach (against Murray's rules), guaranteeing rental income or a property-value jump, refusing to name the licensed entity, large unexplained deposits, vague utility/site-work language, no written change-order process, or a firm "complete price" before anyone has looked at your site.
One of our commercial partners, Nest Tiny Homes, is a Salt Lake County–based builder that focuses on compact ADUs — a natural fit for Murray's one-story, 1,000-square-foot, two-bedroom detached envelope. We disclose this partnership plainly. As with any builder, confirm current Utah licensing (DOPL) and Murray permit experience yourself before you contract, and treat any past project as an illustration, not a promise that the same design, cost, or approval will transfer to your lot.
Our process checks property fit first, gives you a planning-level cost range, and — when a project looks viable and you ask to be connected — may share your details with one matched professional or builder partner; we may receive compensation. It does not produce a permit approval or a guaranteed bid, and you should confirm any builder's Utah license before contracting.
When an ADU is not the right project
An ADU is not automatically a smart project just because Utah has become more ADU-friendly. The right project depends on your lot, city, utilities, budget, and use case — and in Murray specifically, a few situations should make you pause before spending on design:
- A detached plan on a lot under 10,000 sq ft, or a rear yard that can't clear the setbacks or fit four total parking spaces, or a site with no real access for excavation.
- A short-term-rental or absentee-landlord goal, which conflicts with Murray's rental and owner-occupancy rules.
- A budget that only works in the best case — one that excludes utilities, site work, engineering, parking, or a contingency isn't a real budget yet.
If any of those describe you, the answer isn't always "no ADU." Sometimes it's a different type (an internal suite instead of a detached build), a smaller-scope remodel, or waiting until a financing or utility issue is resolved. Better to learn that in a short feasibility check than after a design deposit.
What to have ready before you request an estimate
A useful estimate starts with property facts, not just a square-footage wish. Gathering these ahead of time lets a first estimate surface real uncertainty instead of hiding it:
- Property address and, if you have it, your parcel/lot info and approximate lot area
- Your main home's approximate floor area, plus any existing plans, survey, or assessor sketch
- Photos of the area where you'd put the ADU
- Intended ADU type, rough size, and bedroom count
- Whether it's for family or long-term rental, and your owner-occupancy plan
- Current parking layout and the access path to your rear/side yard
- Known easements, your electrical panel/service info, and sewer/water locations if you know them
- A realistic budget band, financing status, and desired timing
- Any HOA or private-covenant documents. City permission and HOA rules are separate layers — though under Utah law an HOA generally can't prohibit the construction or rental of a code-compliant internal ADU. Have your governing documents reviewed for your specific situation.
Not in Murray? Nearby cities with separate ADU rules
Murray ADU builder FAQ
Sources & how we keep this current
We check the facts on this page against official sources and re-verify them on a schedule because city ordinances, fees, and state law all change:
- Murray City Municipal Code, Chapter 17.78 (Accessory Dwelling Units), §§17.78.040 (attached), .050 (detached), .060 (affidavit), .090 (short-term rentals), .100 (business license)
- Murray City — Accessory Dwelling Units
- Utah Code §10-21-303 (internal ADU statute) and §11-36a-202 (impact-fee provisions)
- Utah Code §10-21-304 / S.B. 284 (2026) (detached ADU provision)
- Utah Code §57-8a-209 and §57-8a-218 (Community Association Act — HOA limits on internal ADUs)
- Utah Department of Commerce — ADUs and HOA/ADU guidance
- Utah Division of Professional Licensing (DOPL) — contractor license verification
Official sources control the legal and permitting facts. Cost and timeline figures are our own planning estimates and stay estimates until a specific property and scope are reviewed. Rules can change; we date material corrections and update this page when Murray's ordinance, fees, or the state law change. Property-specific questions need verification before you make design, permitting, construction, rental, or purchase decisions.
Last verified: July 2026