ADU Electrical Panel Upgrade in Utah: Cost, Permits, and When You Actually Need One

Quick answer: will your ADU need an upgrade?

Adding an ADU adds electrical load — the total power your home draws at once. Whether your existing service can absorb it comes down to a licensed electrician's load calculation, not the age of your panel. Use the table below to gauge your risk before you spend money on plans or quotes.

Will my Utah ADU need an electrical panel upgrade?

Maybe — but not always. A second kitchen, laundry, heating and cooling, water heating, or a detached structure can push your home past what its current electrical service was built to carry. The right first move isn't "upgrade the panel." It's a load calculation and a feasibility check for your specific home and ADU type.

Here's the short version by ADU type. (Definitions: an internal ADU is created inside your existing home, like a basement apartment; a detached ADU is a separate structure, like a backyard cottage or a converted detached garage.)

Panel upgrade, subpanel, service upgrade, or separate meter — what's the difference?

Homeowners often say "panel upgrade" when the real issue is something else. The distinction matters, because each path carries different cost, permits, inspections, and timeline.

A useful way to think about it: a subpanel moves power around, a service upgrade brings more power in, and a separate meter changes how that power is billed. They solve different problems.

What actually triggers a panel or service upgrade?

The two big triggers are added load and limited existing capacity. An older 100-amp service, a panel with no open breaker slots, or an all-electric ADU can each push a project toward panel, service, or utility work.

A gas-appliance ADU on a home with light existing loads may need far less. That's exactly why the calculation — not a rule of thumb — decides it.

How much does an ADU electrical panel upgrade cost in Utah?

For early planning, use $2,000–$5,000 as a realistic range for a straightforward Utah panel or service upgrade, with simpler like-for-like swaps sometimes running less and detached, high-capacity, or utility-side work running more. These are estimates, not quotes — the load calculation and your utility set the real number.

*Estimates only. Published Utah electrician sources put common residential panel upgrades in roughly the $2,000–$4,000 range, and 200-amp service upgrades around $2,500–$5,000. ADU-specific trenching, meter-base work, utility-side work, 400-amp service, old-wiring corrections, or detached-unit service can exceed those figures. Your actual price depends on the items below.

How the electrical scope changes by ADU type

Your ADU type shapes the electrical work more than almost anything else. A basement unit often runs off a subpanel from your existing service; a detached unit usually needs power routed across the yard.

For total-project budgeting beyond electrical, see our Utah ADU cost guide.

Do you need a permit and a licensed electrician in Utah?

Assume both a permit and an inspection. Panel, service, meter, and utility work is code-regulated — and for a project this specialized and utility-coordinated — is best handled by a licensed Utah electrical professional. You can verify a license through the Division of Professional Licensing (DOPL) .

Utah law does allow the owner of a single-family home to do their own electrical work, but that's rarely the right call for ADU service work, and the permit and inspection still apply either way.

How the process typically runs in Utah

(Using West Valley City's published service-upgrade process as a representative example)

1. 1The permit is pulled — by the licensed electrical contractor doing the work, or, for a single-family home, the homeowner.
2. 2The work is completed to code.
3. 3The city inspects and approves it.
4. 4The city then authorizes Rocky Mountain Power (or your local utility) to connect or reconnect power.

Which electrical code does Utah use for ADUs?

Utah adopts the 2023 National Electrical Code (NEC) statewide, with Utah amendments, under the State Construction Code (Utah Code § 15A-2-103). Your ADU's wiring, panel, and service work must meet it. The practical takeaway: your licensed electrician designs to the currently adopted code, so you don't have to track editions yourself.

Does an ADU need its own electric meter in Utah?

Don't assume it can — or must. Whether an ADU gets a separate electric meter is a local (city and utility) question, not a statewide one, and the rules differ for internal vs. detached units. Some Utah cities prohibit separate ADU meters outright; others allow them for detached units with utility approval.

For example, Millcreek's ADU rules state that ADUs are not allowed to have separate utility meters — all utilities must be served from the main single-family home — though a secondary meter to monitor usage may be allowed if you work with your utility provider. Other cities set different rules, and some require detached ADUs to be separately metered. A Utah Property Rights Ombudsman opinion has also addressed cases where a local ordinance required an accessory unit to share the primary home's service. The pattern across Utah: your city's ordinance and your utility control this, so it must be confirmed for your specific address and ADU type.

A few things to sort out before you count on separate metering:

• Is the ADU internal, attached, detached, or garage-based? Rules can differ by type.
• Does your city allow, require, or prohibit a separate meter for your ADU type?
• Does your utility have to approve the meter or service change (and are there fees)?
• Is your goal tenant billing, or capacity? A meter doesn't solve a capacity problem on its own.

What about "all-electric" rules and solar?

As of this guide's last verification (July 2026), we did not find a Utah statewide, ADU-specific mandate — comparable to California's — requiring new ADUs to include solar panels or be battery-ready. That's a common point of confusion because so much ADU-electrical content online is written for California. Utah's energy requirements come from the Utah-amended energy code, and any solar decision is generally yours to make.

How Rocky Mountain Power (or your utility) can affect your timeline

If your ADU only needs interior circuits, utility involvement may be minimal. If it needs a service upgrade, a new service, a line extension, meter-base work, or trenching, then Rocky Mountain Power — or a municipal utility, if your city runs its own power — becomes part of the schedule.

How long does an ADU electrical upgrade take?

Contractor-published timelines suggest the panel work itself is often a single day, with power usually back on the same day. Add roughly a day if the service mast or a utility disconnect/reconnect is involved. The real wild card is the utility: if a new service, a larger service drop, or a transformer upgrade is required, coordination and inspections can add significant time — sometimes weeks or more, depending on utility scheduling and equipment.

ADU electrical feasibility scorecard

Use this quick self-screen before you request estimates. It doesn't replace an electrician, engineer, city review, or utility review — but it tells you whether electrical should be treated as a major feasibility and budget item.

The honest part: an ADU isn't automatically a smart project

Utah has become more ADU-friendly, but that doesn't mean every ADU pencils out. Electrical is one of the most common hidden budget-busters: a maxed-out old panel, a long trench to a detached unit, or a utility transformer upgrade can add thousands you didn't plan for. Parking rules, setbacks, owner-occupancy requirements, HOA restrictions, and site conditions can all change the math too.

That's not a reason to walk away — it's a reason to look before you leap. The right project depends on your lot, your city, your utilities, your budget, and your use case. A feasibility review exists to surface these costs before you spend money on plans or get emotionally committed to a design.

What to gather before you ask for ADU electrical estimates

The faster you can show your ADU type, city, existing panel, planned loads, and site layout, the better and more accurate your estimate conversations will be.

How to read these rules: what's statewide, what's local, what's an estimate

One reason this topic feels confusing is that some rules are set at the state level and are the same everywhere, while others are decided by your city and utility — and the costs are neither.

Frequently asked questions

What we checked (sources)

We built this page from official and primary sources, and used cost figures from current Utah electrical contractors. Homeowner forums informed the questions we answered, but not the legal, cost, or code facts. Rules, fees, and cost ranges change — where a rule depends on your city, county, or utility, it must be verified for your specific property.

• 1.Utah Property Rights Ombudsman ADU overview — Utah Code § 10-21-303 (municipalities) and § 17-80-303 (counties): internal ADUs are a permitted use in residential zones, subject to enumerated local restrictions
• 2.Utah SB 284 (2026 General Session) — requiring most cities to allow qualifying detached ADUs (generally on residential lots of at least 11,000 square feet), effective October 1, 2026
• 3.Utah Code § 15A-2-103 — adopting the 2023 National Electrical Code with Utah amendments
• 4.Utah Code § 15A-4-601 — no local amendments to the NEC are adopted
• 5.Utah Division of Professional Licensing (DOPL) — Electrical licensing
• 6.West Valley City — Residential Electrical Service Upgrade process (representative Utah example)
• 7.Millcreek City ADU page — example of a local separate-meter restriction
• 8.Rocky Mountain Power — builders and contractors resources
• 9.Utah Home Electric — published panel upgrade cost range ($2,000–$4,000 for common panel upgrades)
• 10.At Your Service Pros — published service upgrade cost range ($2,500–$5,000 for 200-amp service upgrades)