New Detached ADU in Pomona - One Fixed Price, Permits Handled

Fast, Reliable New Detached ADU Across Pomona

A new detached ADU in Pomona typically runs $285,000-$420,000 all-in for a custom build, or $195,000-$310,000 for a prefab or modular install, with drawings through final inspection. Every project is quoted at a single written price before any work begins, per Haven Standard Clause 1. If you’re on a 7,000-plus sq ft lot near Lincoln Park, downtown, or the Cal Poly Pomona corridor, your property likely already has the alley-accessed rear garage that makes Pomona one of the most ADU-ready cities in LA County.

Call (951) 476-1467

We coordinate design, permitting, and construction from our Los Angeles office, with crews serving Pomona locally. Call (951) 476-1467 to schedule your free estimate.

Why Ellery ADU Studio Rialto Is Pomona’s Preferred New Detached ADU Company

We’ve designed, permitted, and built more than 900 ADUs since 2015, the year California’s ADU laws shifted. A significant share of those projects sits in Pomona and the eastern San Gabriel Valley. Our clients in this market aren’t weekend DIYers. They’re homeowners who bought between 2015 and 2025 at historically high prices and are now treating an ADU as a long-term income-producing asset.

Pomona’s building department has specific expectations around garage legalization, ember-resistant venting, and heat-load calculations that coastal contractors routinely miss. We know them because we’ve navigated them repeatedly. Our license number appears on every page, and our crews are background-checked and uniformed. Under the 365-Day Done Right Promise, if the finished ADU isn’t built to the permitted drawings, we make it right - in writing, before the project starts.

A live person answers calls 24/7. No voicemail queue. No callback that doesn’t materialize.

Our New Detached ADU Services in Pomona

Custom Built ADU

Custom builds are where lead times, not labor, set your calendar. In Pomona, we regularly specify architectural glass, custom millwork, and specialty finishes that coordinate with the original Craftsman or Spanish Revival character of the main house. A recent project near Lincoln Park paired white oak cabinetry with blackened steel hardware to match a 1924 bungalow’s original window grilles. The 16-week lead time on the European hardware was locked in writing before we ordered. That’s how Haven Standard Clause 3 works: your price is fixed before long-lead items are committed.

Prefab ADU Installation

Prefab systems from Abodu and Cover can compress your build schedule significantly, but only if the pre-construction work is handled correctly. In Pomona, that means legalizing any unpermitted garage modifications before the prefab unit arrives, upgrading electrical service from 60 or 100 amps, and specifying mini-split systems rated for 105°F-plus heat events. We coordinate Abodu and Cover systems under the same single contract that covers your permit set and site prep. No designer-builder blame gap.

Modular ADU

Modular construction - factory-built modules craned into place - works well on Pomona’s larger lots with alley access. Dvele and Mighty Buildings units arrive 80-90 percent complete, which cuts on-site construction time. The tradeoff is front-loaded engineering: Pomona’s building department requires full structural calculations and ember-resistant venting documentation before they’ll issue the modular set permit. We handle that documentation in-house as part of your permit set.

Studio ADU

Studio ADUs in Pomona make strong rental sense given Cal Poly Pomona’s sustained demand. A 400-500 sq ft studio on a Lincoln Park alley lot can command rents that offset construction costs faster than almost any comparable investment in LA County. We design these units with kitchenettes that meet Pomona’s definition of “efficiency dwelling,” full bathrooms, and the mini-split capacity to handle summer heat without constant cycling.

1-Bed & 2-Bed ADU

One-bedroom and two-bedroom detached ADUs are where Pomona’s lot sizes really pay off. A 750 sq ft 1-bedroom or 1,000 sq ft 2-bedroom unit fits comfortably within setback requirements on most 7,000-plus sq ft lots near downtown or the Cal Poly corridor. These configurations attract faculty and graduate students seeking longer-term housing than dorm life allows. We specify James Hardie siding and Tuff Shed structural elements where they match the durability requirements and aesthetic goals of the project.

Our New Detached ADU team handles every phase under one contract at one written price.

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Trusted Brands We Service in Pomona

We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, and James Hardie - all within the same single contract that covers your design and permitting. For Pomona’s climate, we typically lean on Abodu and Cover for their thermal performance ratings, and James Hardie for ember-resistant exterior finishes that satisfy Santa Ana wind requirements. We don’t drop-ship and disappear. We stock critical components locally, coordinate delivery to your alley or driveway, and manage the installation sequence so your project isn’t waiting on a single backordered item.

Common New Detached ADU Problems We See in Pomona Homes

• Unpermitted garage additions from the 1950s-1980s. Pomona’s alley garages were commonly expanded without permits. The building department flags these during plan check and requires full legalization before your New Detached ADU permit can proceed. We budget for this upfront after our initial site assessment.
• Aging electrical and plumbing infrastructure. Pre-1960 homes near Lincoln Park and downtown routinely have 60-100 amp panels, galvanized supply lines, and failing sewer laterals. These must be upgraded before final inspection. We identify them in our first visit and price the upgrade into your written quote.
• Coastal-spec HVAC and venting. A mini-split rated for mild Santa Monica weather will fail inspection and underperform in Pomona. We specify systems rated for 105°F-plus operation and ember-resistant vents that satisfy California’s wildfire-urban interface requirements.
• Underestimated lead times on custom finishes. The Italian tile, custom cabinetry, or architectural glass you want isn’t sitting in a warehouse. We lock lead times in writing before ordering, and your price is fixed before any deposits go to suppliers.

Pricing for New Detached ADU in Pomona, CA

We Also Serve Cities Near Pomona

Our crews work throughout the eastern San Gabriel Valley and western Inland Empire, including Pomona, Montclair, Ontario, Upland, and Chino. Each city has distinct building department expectations, and we permit regularly in all five jurisdictions.

FAQs - New Detached ADU in Pomona