ADU Company in Muscoy, CA
Muscoy is an unincorporated San Bernardino County community where building an ADU means working with county rules, not city hall. Most homes here are 1950s-to-1970s ranch-style houses on lots big enough for a detached unit, but many carry unpermitted garages or casitas that have to be sorted out before a permit will move. We’re Lodgewick ADU Builders, the ADU company of the Kingswell family, and we put a written price in your hand before any work starts. Call us at (254) 602-5618 for a free estimate.
Why Muscoy Homes Are Different
Muscoy sits on the San Bernardino Valley floor, where summer highs routinely pass 105°F. That means a backyard ADU here needs real insulation and its own mini-split system. Extending the main home’s undersized HVAC into a new unit simply doesn’t work in this heat, and we design for that from day one. The area also sits in a high-wind Santa Ana corridor, so San Bernardino County Fire’s exterior-material and vegetation-setback rules come into play on nearly every detached structure we plan.
A significant share of Muscoy parcels are served by the Muscoy County Water District, and some older lots still rely on private septic. Confirming water and sewer capacity with the county and the district is a mandatory first step before any ADU design is finalized. We’ve seen projects stall for months because nobody checked hydrant flow or septic capacity up front. We handle that legwork early so the permit application is complete on submission.
Our Main Muscoy Services
Most Muscoy homeowners call us about one of two things: adding square footage to the existing house, or converting a garage into livable space. Here’s what each looks like in this community.
Home Addition Contractor in Muscoy
Home additions in Muscoy often mean expanding a 1950s or 1960s ranch that was built small. We tie new framing into the existing structure, match rooflines, and bring the whole addition up to current county energy and fire codes. Because many Muscoy lots carry unpermitted room additions from decades past, we also work with San Bernardino County to legalize or remove nonconforming structures before the new work is approved. Every addition gets a written price before we start. Learn more about Home Addition Contractor in Muscoy.

Garage Conversion Contractor in Muscoy
Garage conversions are popular in Muscoy because the older housing stock tends to have oversized two-car garages that rarely hold cars. We convert existing garage shells into permitted living space, addressing insulation, electrical service, and egress windows to satisfy county requirements. A common wrinkle here is an unpermitted garage built or altered without county sign-off; we resolve that before framing begins. Costs are always delivered as a written line-item quote. Read more on our Garage Conversion Contractor in Muscoy page.

ADU Builders in Muscoy
Detached ADUs make sense on Muscoy’s larger lots, but the unincorporated county process adds layers: San Bernardino County Fire reviews fire-flow adequacy, and some blocks don’t meet minimum hydrant flow. We coordinate with the Muscoy County Water District on system capacity before submitting anything. From foundation to roof, we manage the build under The Kingswell Guarantee, which means a written guarantee on every project. See the details on our ADU Builders in Muscoy page.

What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Muscoy
We work with established ADU and materials brands including Cover, Dvele, and Mighty Buildings, chosen to fit each Muscoy lot’s grade, setback, and fire-flow constraints. Parts and panels are ordered per project and staged locally before crews arrive. See our brands for more on what we recommend and why.
Pricing for ADU Company in Muscoy, CA
| Service | Typical range in Muscoy |
|---|---|
| Detached ADU (prefab, one-bedroom) | $175,000 – $310,000 |
| Detached ADU (site-built, one-bedroom) | $220,000 – $380,000 |
| Detached ADU (two-bedroom) | $280,000 – $450,000 |
| Attached ADU / JADU conversion | $120,000 – $230,000 |
| Garage conversion to studio ADU | $95,000 – $160,000 |
| Garage conversion to one-bedroom ADU | $125,000 – $205,000 |
| Home addition (primary bedroom suite) | $90,000 – $180,000 |
| Home addition (family room extension) | $70,000 – $150,000 |
| Home addition (second-story, per square foot) | $250 – $450 |
| Kitchen expansion (single room) | $55,000 – $110,000 |
Prices in Muscoy run higher than in adjacent incorporated cities because county fire-flow reviews, water-district capacity checks, and unpermitted-structure remediation all add front-end cost and time. The price we give you in writing before work starts is the price you pay. No change orders at the door.
Neighborhoods We Serve in Muscoy
We cover the full Muscoy area, including the streets around State Street, the parcels along Darby and Duffy, and the blocks near the Muscoy County Water District’s service boundary. Typical scheduling runs two to four weeks from signed agreement to crew arrival, depending on county permitting volume.
- State Street corridor
- West Muscoy (near Rialto border)
- East Muscoy (near Highland border)
- Darby/Duffy area
- Muscoy County Water District service area
Service Area – Cities Near Muscoy
Beyond Muscoy, we serve homeowners across the Inland Empire and the broader Southern California region. If you’re in Los Angeles, CA, Long Beach, CA, Anaheim, CA, or Riverside, CA, the same Kingswell Guarantee applies: written price first, clean job site, written guarantee on every project.
Serving Muscoy, CA - Our Local Coverage Area
We’re based in the Muscoy area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU Company in Muscoy
Budget six to twelve months for San Bernardino County approval, assuming water and fire-flow capacity checks come back clean. Unpermitted structures on the lot will extend the timeline. We handle the county and district paperwork so the application is complete on first submission. Call (254) 602-5618 and we’ll walk you through what applies to your parcel.
Yes. All ADU work routes through San Bernardino County Building & Safety and Planning Division, with County Fire reviewing fire-flow adequacy. There’s no city hall involved, but the county’s setback, utility, and fire rules are strict. We pull the permits and schedule the inspections. Call us for a free estimate.
No. Every project operates under The Kingswell Guarantee, which starts with a written price before any work begins. If county remediation of unpermitted work expands scope, we document the change in writing and get your sign-off before proceeding. Estimates are free at (254) 602-5618.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Muscoy Customers Say
"A whole backyard ADU from scratch. Terrified me going in, but they kept me updated weekly and there were no nasty surprises. Quality work and a fair price."
- Noreen Fletcher"Built a backyard unit for my mother in law. They handled the permits, gave me a real timeline, and stuck to it within a few days. The written price is what we paid, which anyone who's done construction knows is rare."
- Dennis Fairchild"Garage conversion into a studio for our teenager. Honest about what was realistic and what wasn't, finished close to schedule, and cleaned up the site daily."
- Marcus Beaumont