Old Town Star
The original grid around Star Park and State Street — smaller in-town lots, mature trees, and walkable to the library and post office. ADUs here lean toward the smaller studio plans (Goldfinch, Waxwing) where setbacks are tighter.
Star, Idaho
Star ADU builder
Detached cottages and garage-combo ADUs built for Star's acreages, septic systems, and rural feel — from Old Town Star to the Beacon Light corridor.
ADUs in Star
Why Star homeowners are building backyard homes
Star is the smallest city in our service area and the fastest-growing percentage-wise — population has roughly doubled in the last decade, and the Hwy 44 corridor between Eagle and Middleton looks nothing like it did five years ago. What hasn't changed is the feel: pasture, horses, irrigation ditches, and lots measured in acres rather than square feet. That's why people move here, and that's the lens we use when we design an ADU for a Star property.
Our work in Star is mostly detached cottages on larger lots — half-acre to a couple of acres — where there's room to place an accessory dwelling without crowding the main house. Garage-combo plans (Sandpiper and Osprey) get built more often here than anywhere else we work, because Star homeowners actually have somewhere to put a 24x24 footprint. We also see a lot of in-law suites and home offices for families relocating from California, Oregon, and Washington who want a separate space for visiting parents or remote work.
Permitting in Star runs through the city's Unified Development Code, with most accessory-dwelling rules adopted from Ada County's base code. The big variables on a Star lot are usually septic placement, well location, and whether the property sits inside or outside a design-review subdivision. We handle the site-specific work up front so you know what's buildable before you commit to a plan.
- ~14,000
- Star population (2024 est.)
- ~100%
- Population growth, last 10 years
- 0.5-2 ac
- Typical lot size on Beacon Light & Hwy 44
- $1,300-1,500
- Median 1-bed rent
Neighborhoods
Where we build in Star
We've worked across most of Star — here are the neighborhoods most homeowners are asking us about.
Beacon Light Corridor
Half-acre to multi-acre properties along Beacon Light Rd north of town. Big lots, often with outbuildings or shops, and ideal for detached garage-combo ADUs (Sandpiper, Osprey) without disturbing existing landscaping.
Star Crossing
Newer subdivision off Hwy 44 with a mix of lot sizes. CC&Rs and design review apply on most lots — we coordinate elevations and exterior finishes so the ADU reads as part of the same property.
River Birch & River Heights
Communities closer to the Boise River corridor on Star's south edge. Floodplain and setback considerations are real here; we pull FEMA flood maps before siting anything near the river.
Sky Mesa (Eagle/Star border)
Foothills-feel acreages straddling the Eagle and Star line. Larger custom homes with room for a 695 sq ft Kestrel as a true guest house or in-law suite.
Sage Hills & Hwy 44 Acreages
Agricultural and equestrian properties on the outskirts — often 1 to 5 acres with septic, well water, and shop buildings. ADUs here function as ranch hand quarters, in-law suites, or rental income alongside the main residence.
Zoning + Permits
Star's ADU rules in plain English
Star's UDC permits accessory dwellings on most residential lots, with rules pulled largely from Ada County's accessory-dwelling base code. Larger lots get more flexibility; in-town lots and design-review subdivisions get tighter scrutiny. Septic and well placement drive the site plan more than zoning does on most acreages.
Larger lots, more flexibility
Star's residential lots tend to run from a quarter-acre in Old Town up to several acres along Beacon Light and Hwy 44. Bigger lots generally allow detached ADUs up to roughly 700-900 sq ft (we confirm the specific cap against your lot's zoning district before pricing).
Setbacks for accessory structures
Typical accessory-structure setbacks on Star residential lots are 10 ft or more on the side and 15 ft or more on the rear, with front setbacks matching the primary residence. Acreage parcels can have larger setbacks driven by zoning district rather than the structure type.
Septic and drainfield clearances
Most Star properties outside city sewer use septic. Central District Health typically requires the ADU footprint, foundation, and any utility trenches to clear the septic tank and drainfield by a set distance, plus replacement-area reserve. We pull your existing septic permit and as-built before final siting.
Owner-occupancy
Star generally requires the property owner to occupy either the primary residence or the ADU. We hedge here because the rule has been refined a few times in recent UDC updates — we confirm the current language with the city before submitting permits.
Design review in CC&R subdivisions
Newer subdivisions like Star Crossing, parts of Sky Mesa, and several River-corridor communities have HOA design review on top of city permitting. Roof pitch, siding, and color often need to match the primary residence. We submit elevations to the architectural committee in parallel with the city permit.
Parking
Star typically requires one additional off-street parking space for the ADU. On larger lots that's a non-issue; in Old Town we sometimes need to redesign the driveway or add a hard-surface pad.
Why Star
What makes Star a strong ADU market
Rural feel, room to build
Star lots are bigger than Eagle's in most subdivisions — half-acre to two-acre parcels are common. That gives you actual placement options for a detached ADU instead of squeezing one into a side yard.
Detached ADU + garage combos fit here
Our Sandpiper (396 sq ft + garage) and Osprey (376 sq ft + garage) plans get built more in Star than anywhere else we work. There's room for the footprint, and homeowners want both the living unit and covered storage for trucks, tractors, or RVs.
Growth trajectory makes rentals viable
Star's rental market used to be too thin to underwrite an ADU as pure rental income. Population doubling in 10 years has changed that — long-term and traveling-professional rentals at $1,300-1,500 for a 1-bed are now realistic on the right property.
In-law suites for new arrivals
A lot of Star's growth is families relocating from out-of-state and bringing aging parents along. A 695 sq ft Kestrel functions as a private 2-bedroom suite — separate enough for independence, close enough for daily check-ins.
Equestrian property helpers
Acreage owners with horses, livestock, or working land often need a small unit for help — a property manager, ranch hand, or extended family member who handles morning chores. A studio or 1-bed ADU is the right scale for that without overbuilding.
Easy commute to Eagle and Boise
Hwy 44 puts downtown Eagle 10 minutes east and downtown Boise about 25 minutes. That makes Star ADUs attractive to remote workers and commuting renters who want acreage living without giving up access to the metro.
Recommended Plans
Best pre-approved plans for Star lots
The City of Boise's pre-approved plans work in every Treasure Valley jurisdiction. Here are the picks that fit this city's lots and rental market best.
Type G-1The Sandpiper
From $145k
396 sq ft · Studio · 1 ba
The Sandpiper (396 sq ft studio + attached garage, $145k) is our most-built plan in Star. The garage absorbs trucks, tractors, ATVs, or workshop space that Star homeowners actually have, and the studio works as a rental, guest space, or office.
See the The Sandpiper
Type G-2The Osprey
From $140k
376 sq ft · Studio · 1 ba
The Osprey (376 sq ft + garage, $140k) is the same idea with a different roofline and footprint — better suited to lots where the long axis runs east-west or where a particular tree or septic field constrains placement. We pick between Sandpiper and Osprey based on the site plan.
See the The Osprey
Type DThe Kestrel
From $245k
695 sq ft · 2 bd · 1 ba
The Kestrel (695 sq ft 2-bed, $245k) is the in-law-suite plan. Two bedrooms, full bath, full kitchen, real living room — enough space that visiting parents or adult kids don't feel like they're living in a guest room. Star's larger lots make the bigger footprint easy to site.
See the The KestrelStar Lot Realities
What ADU homeowners in Star actually check
Local specifics — not generic Treasure Valley copy.
What to check first on a Star lot
Star is the fastest-growing of the Treasure Valley cities and the rural-fringe characteristics dominate — pull your parcel from the Ada County Assessor for lot dimensions and verify sewer vs septic first. Sewer extension from City of Star is a real number on rural-fringe lots; septic vs sewer changes the project's cost by $15-30k. Some Star lots still carry irrigation easements that affect siting.
Common Star lot types
Star lots skew big — 1/2-acre and full-acre lots are common in older sections of town, with newer subdivisions building closer to 80-100' wide. The acreage profile means Star is where homeowners most often build a custom ADU larger than the pre-approved cap (still subject to City of Star code, which caps similarly to Boise). Lots adjacent to Star Road and the Highway 44 corridor are the most utility-ready.
Detached vs garage conversion in Star
Detached almost always wins in Star. Lots are large enough that any pre-approved plan fits without setback gymnastics. Garage conversions are less common because newer Star construction lacks the detached garages that make conversions natural, and the homeowners on older Star lots typically want a separate accessory dwelling rather than to give up garage space. The Kestrel is a frequent Star pick because the rural-fringe rental market supports larger units well.
Cost considerations in Star
Star builds run at or slightly above Boise baseline. The cost variables: (1) septic systems on rural-fringe lots, (2) longer utility runs adding $1-3k per service, (3) sewer extension when the existing connection is at the property edge but the dwelling sits 100+ feet back, and (4) sometimes a sub-station-capacity-limited Idaho Power feed that triggers transformer upgrades. The lot check identifies these before contract.
"We're on two acres off Beacon Light with a septic system and a well, and I figured siting an ADU was going to be a mess. The team pulled our septic as-built before we even signed, came back with two placement options, and ended up with a plan that kept the drainfield reserve intact and didn't touch a single tree. My mom moved into the Kestrel last month."
Dana R.
Kestrel — Beacon Light Rd · Star, ID
FAQ
Star ADU questions, answered
I'm on septic. Can I still build an ADU?
Yes, on most Star acreages. The site plan has to clear the septic tank and drainfield by Central District Health's required setbacks, and you usually need a verified replacement-area reserve. If your existing septic was sized for a 2-bedroom main house and you're adding a 2-bed ADU, the system may need to be expanded or upgraded — we figure that out before pricing the build, not after.
What about well water? Does an ADU change anything?
If you're on a private well, adding an ADU means an extra household drawing on the system. For most Star wells with reasonable yield this is a non-issue, but on older or shallower wells we recommend a well-flow test before committing. Setbacks between the ADU foundation, septic components, and the wellhead also have to be respected — typically 50 ft or more from any septic feature to the well.
What setbacks apply on a rural Star property?
Setbacks depend on your zoning district more than the fact that you're rural. On a typical R-2 or larger residential lot, accessory structures usually need 10 ft or more on the sides and 15 ft or more on the rear. Agricultural-zoned acreages can have different rules — sometimes more permissive, sometimes more restrictive depending on the parcel. We pull your specific zoning before we site the building.
Does my subdivision require design review?
Some do, some don't. Old Town Star generally doesn't. Star Crossing, parts of Sky Mesa, River Birch, and several other newer communities have HOA architectural committees that review elevations, materials, roof pitch, and color. We collect your CC&Rs early and submit to the committee in parallel with the city permit so it doesn't add weeks to the timeline.
Can I keep my horses or livestock on the same property as the ADU?
Generally yes, if your zoning already allows them. An ADU doesn't change the property's right to keep animals — but barn and corral setbacks from the ADU may apply, and you'll want to think through fly, dust, and odor placement so the unit is actually rentable or livable. We've sited several ADUs on equestrian Star properties without conflicts.
Will an ADU pencil as a rental in Star, or is it really just for family?
Both, depending on the property. Star's rental market is thinner than Boise or Meridian, but median 1-bed rent is now in the $1,300-1,500 range and rising as the city grows. A studio or 1-bed ADU on a Star property is realistic as a long-term rental; we also see strong demand for furnished month-to-month from traveling professionals working in the Treasure Valley. In-law suites and home offices for the homeowner's own use are still the most common use case here, though.
Nearby Areas
We also build in nearby cities
Zoning verified against City of Star / Ada County code — last reviewed May 2026.
Star, Idaho
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