Fast, Reliable New Detached ADU Across Bloomington
A new detached ADU in Bloomington typically runs $220,000-$420,000 all-in, from permit set through final County inspection, with most projects moving from signed contract to certificate of occupancy in 8-14 months. Because Bloomington is unincorporated San Bernardino County, your permit routes through County Land Use Services, not a city building department - a distinction that derails contractors who assume they’re working in Fontana or Rialto. Our New Detached ADU team has pulled permits through the County’s Valley Division since 2015, and we schedule and dispatch from our Inland Empire office so Bloomington homeowners aren’t waiting on crews based two counties away. Call (909) 637-3715 to schedule your free estimate.
Why Ellery ADU Studio Fontana Is Bloomington’s Preferred New Detached ADU Company
We’ve designed, permitted, and built ADUs across the Inland Empire since 2015 - more than 900 projects, every one with a written price before work started and a documented photo record when work was complete. Bloomington homeowners find us because our name shows up in permit data: we know the County’s RL zone clearances, the agricultural-reclassification process, and the exact submittal package Land Use Services expects for a detached unit on a half-acre lot.
Our crews serve Bloomington from our Riverside-San Bernardino metro office. That means no three-hour dispatch windows from Orange County or LA. When we open walls on a 1970s ranch off Slover Avenue or a 1960s build near Cedar Avenue, we find what we find, document it with photos, and price any repair in writing before we touch it - Haven Standard, Clause 5 (No Surprises).
Nadia Ellery built this studio on a single contract covering design, permitting, and construction. No designer blaming the builder. No builder blaming the drawings. One written price, one accountable team.
Our New Detached ADU Services in Bloomington
Custom Built ADU
A custom built ADU in Bloomington runs $280,000-$420,000 all-in. On RL-zoned lots, we regularly design 1,200-square-foot detached units with full kitchens and laundry that simply wouldn’t clear setback or lot-coverage rules in incorporated Rialto or Fontana. We produce the permit set in-house, submit to County Land Use Services ourselves, and build from our own drawings - so when the County plan checker calls out a footing detail or a fire-separation requirement, we revise and resubmit without a third-party architect disappearing for three weeks.
Prefab ADU Installation
Prefab ADU installation in Bloomington typically ranges $220,000-$340,000, including foundation, utility tie-in, and County final. We specify and coordinate systems from Cover, Mighty Buildings, and Boxabl within the same single contract - not a separate purchase from the manufacturer plus a separate contractor who may or may not have County experience. On Bloomington’s larger lots, crane access is rarely the constraint it becomes in denser neighborhoods; the real work is the County electrical and plumbing tie-in, which we handle directly.
Modular ADU
Modular ADU projects in Bloomington fall between prefab and custom - $260,000-$380,000 - with factory-built modules set on a permanent foundation and finished to match the main house. We work with Dvele and other modular suppliers to spec the unit, then manage County structural review, foundation engineering, and utility connections ourselves. The Haven Standard Clause 1 written price covers the full scope: module, transport, set, finish, and inspection.
Studio ADU & 1-Bed & 2-Bed ADU
Studio ADUs in Bloomington start around $220,000-$280,000; 1-bed units run $260,000-$340,000; 2-bed configurations reach $320,000-$420,000 depending on kitchen and laundry spec. On RL-zoned properties near Cedar Avenue or along Valley Boulevard corridor, we’ve fit 2-bed, 2-bath detached units with dedicated HVAC and tankless water heaters that rent at market rate year-round. Every unit gets a right-sized mini-split and spray-foam roof deck - non-negotiable in Bloomington’s 105°F summers.
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.
Before
AfterTrusted Brands We Service in Bloomington
We specify and coordinate prefab and modular systems from Cover, Mighty Buildings, Boxabl, and Dvele - all within our single design-build contract. For site-built work, we source James Hardie siding and Tuff Shed structures where they fit the project. Our Bloomington clients don’t manage manufacturer relationships or wonder whether the crane operator talks to the electrician. We coordinate delivery, set, and County inspection as one scope, one price, one team.
Common New Detached ADU Problems We See in Bloomington Homes
- County permit routed to the wrong department. Contractors accustomed to Fontana or Rialto submit to a city building department that has no jurisdiction. Submittal rejected. Weeks lost. We file directly with San Bernardino County Land Use Services from day one.
- Agricultural accessory structures with reclassification hurdles. That block-wall tack room or stable pad looks like a head start, but if it was permitted agricultural, it needs zone-clearance reclassification to residential. We check this in preliminary research, not after demo starts.
- Cloth-wrapped or aluminum branch wiring in 1960s-1970s ranches. Open the wall to tie in the ADU subpanel and find wiring that hasn’t met code in decades. We write a repair allowance into every contract, then price the panel upgrade in writing before we cut power.
- Undersized cooling for triple-digit heat. A standard HVAC load calc for coastal California fails fast in Bloomington. We spec mini-splits and spray-foam roof decks for the actual climate, not the catalog default.
Pricing for New Detached ADU in Bloomington, CA
| ADU Type | Typical All-In Range | Notes |
|---|---|---|
| Studio ADU (prefab or custom) | $220,000-$280,000 | Includes permit set, foundation, utility tie-in, County final |
| 1-Bed ADU | $260,000-$340,000 | Full kitchen, bath, mini-split; larger units on RL lots at upper end |
| 2-Bed ADU | $320,000-$420,000 | Maximum size allowed under County code; laundry included |
| Custom built, high-spec | $280,000-$420,000 | In-house design, premium finishes, complex utility routing |
These ranges reflect what Bloomington homeowners actually pay - not a teaser rate with half the scope missing. What moves the number: soil conditions for foundation work, distance from main house to ADU for utility trenching, whether the existing electrical service needs upgrading, and whether an old agricultural outbuilding requires reclassification. Under Haven Standard Clause 1, you receive a written line-item price before any work begins. No “call for a quote.” No range that doubles once you’re committed. Call (909) 637-3715 for your free estimate.
We Also Serve Cities Near Bloomington
Our crews work throughout the Inland Empire, including Bloomington, Rialto, Fontana, Riverside, and Mira Loma. Each city carries its own permitting authority - Fontana and Rialto run their own building departments, unlike unincorporated Bloomington - and we file accordingly. Same single contract, same written price, same documented photo record.
Serving Bloomington, CA - Our Local Coverage Area
We’re based in the Bloomington 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 - New Detached ADU in Bloomington
San Bernardino County Land Use Services issues every ADU permit in Bloomington, because Bloomington is unincorporated - there is no city building department. Contractors who submit to Fontana or Rialto by mistake receive a rejection that costs two to four weeks. We file directly with the County’s Valley Division from preliminary design. Call (909) 637-3715 to schedule your free estimate.
Yes - RL zoning on half-acre to two-acre lots typically gives you more lot coverage and setback room than standard suburban zoning in incorporated cities, often allowing a 1,200-square-foot detached ADU that wouldn’t clear in Fontana or Rialto. We verify your specific parcel’s zone, setback lines, and coverage limits during our preliminary site analysis, before we draw a single line. Call (909) 637-3715 for an exact read on your lot.
You can, but only after reclassifying the structure from agricultural accessory to residential use through County Land Use Services - a separate review step that adds time and requires a zone-clearance letter. Many Bloomington parcels have old stables or tack rooms with agricultural permits; we check this in our first site visit and build the reclassification into the project timeline if you want to proceed. Call (909) 637-3715 to discuss whether conversion or new construction makes sense for your property.
Cloth-wrapped or aluminum branch wiring, 100-amp panels that can’t carry the ADU load, and termite-damaged eave framing are routine in 1950s-1980s ranches. On a half-acre RL-zoned lot off Cedar Avenue, our crew found exactly that - plus an undersized feed that needed upgrading before the ADU subpanel could go in. We wrote a repair allowance into the contract at signing, then priced the panel upgrade and reframe in writing before demo. No surprise. No change order you didn’t approve. Call (909) 637-3715 and we’ll show you what our photo documentation looks like.
We spec a properly sized mini-split system and a spray-foam or radiant-barrier roof deck on every detached ADU we build in Bloomington - no exceptions. Standard load calculations designed for milder climates fail here; we’ve replaced undersized units in backyard ADUs that couldn’t hold 78°F by noon in July. Our permit set includes HVAC sizing for actual Bloomington conditions, not catalog defaults. Call (909) 637-3715 to schedule your free estimate.
Ready to price a new detached ADU on your Bloomington property? Call (909) 637-3715 to schedule your free estimate. You’ll receive a written line-item quote before any work begins - Haven Standard, Clause 1 - and a 365-Day Done Right Promise backed in writing.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Bloomington since 2015.