A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across Pomona
ADU construction in Pomona typically runs $180 to $400 per square foot depending on whether you’re converting an existing garage or building new from the slab up. Most Pomona homeowners we talk to are weighing a detached backyard ADU against a garage conversion, and the honest answer is that your lot’s existing conditions determine the real number. We scope every project against Pomona’s older grid, where detached garages, alley access, and mature trees shape the permit and utility work as much as the structure itself. Reed Calloway leads our Pomona crews, and you can reach us at (361) 315-4177 for a written estimate before any work begins.
Key Takeaways:
- Garage conversions in Pomona typically run $120,000 – $190,000; new detached ADUs start around $180,000 and go up from there.
- Your lot’s alley access, existing slab condition, and sewer lateral size drive more cost than the floor plan.
- We price everything in writing before work starts, and every build carries the 365-Day Done Right Promise.
- Fielding ADU Builders handles permits, inspections, utility upgrades, and the full build.
Why Fielding ADU Builders Is Pomona’s Preferred ADU Builders Company
Fielding ADU Builders operates as part of the Garrison Partners family, which has been building to The Garrison Standard since 2006. That standard is not a mission statement on a website. It is a written price handed to you before a single nail is driven, permitted work done by the book, and a one-year guarantee spelled out on paper. If something fails inside that year, we come back and fix it at no charge. That is the entire agreement.
Our crews working in Pomona know the difference between a 1920s bungalow near Lincoln Park and a mid-century tract home north of the 10. That matters when you’re scoping a garage conversion, because ceiling height, slab condition, and sewer lateral placement vary block by block. Reed Calloway runs our Pomona projects personally, and the crew on your lot is background-checked, uniformed, and answerable to one name. You will know exactly who is on your property every day.
We answer the phone with a live person, 24 hours a day. When you call (361) 315-4177, you get a person, not a voicemail queue. We schedule estimates directly, show up in the window we give you, and leave you with a written price you can hold us to. That is the way the Garrison Code works: show up in the window, price in writing, by the book, leave it clean, stand behind it for a year.
Backyard ADU in Pomona
A Backyard ADU in Pomona is a separate living unit built behind the main house, typically 400 to 800 square feet with its own kitchen, bath, and entrance. Most of the lots we build on sit on Pomona’s 1920s to 1950s grid, which means we’re usually working around mature citrus and shade trees, detached garages, and existing electrical service that was never sized for a second dwelling. A new detached ADU in Pomona generally runs $200,000 to $340,000 depending on size, finishes, and how much utility work the lot requires.
Detached Unit Scope
Building a detached backyard ADU in Pomona means starting with a soils report and foundation plan, then running new water, sewer, and electrical service from the street or alley. On older lots, we frequently replace the existing electrical panel and upgrade the gas service at the same time. The structure itself is the straightforward part. The site work – tree roots, drainage, utility trenching – is where the cost concentrates.
Where Trees and Setbacks Add Cost
Pomona’s established neighborhoods have significant tree canopy, and a backyard ADU cannot be placed within the dripline of a mature oak or within the city’s setback requirements without a variance. A setback variance is the city’s written permission to build closer to the property line than the standard rule allows. We scope those approvals before quoting, so the number you see is the number you pay. If the variance is not needed, we don’t put it in the bid.
ADU Construction in Pomona
ADU Construction in Pomona covers the full build from permit application through final inspection, whether you’re converting a garage, adding a junior unit inside the house, or building a detached structure from the ground up. Garage conversions in Pomona typically run $120,000 to $190,000 because the older stock often needs slab work, ceiling height correction, and sewer lateral replacement. Junior ADUs inside the existing house run $70,000 to $120,000, since they reuse the home’s existing systems.
Garage Conversion Reality Check
Quoting a Pomona garage conversion from photos is how change orders happen. A 1940s garage floor is often cracked and below grade, which means cutting and pouring a new slab. Ceiling height may be under the 7-foot-6 California ADU minimum and require raising the roof or re-framing. The sewer lateral that runs to the alley is frequently the original clay pipe, undersized for a kitchen and bath. We put a scope on all of that before you sign anything.
What the Permit Board Actually Shows
Every Fielding ADU Builders job in Pomona carries a posted permit board with the city’s stamp on it. Our crews pull permits for the structure, electrical, plumbing, and mechanical, and every inspection gets scheduled and passed before we move to the next phase. When the final inspection clears, you get a closed permit and a written one-year guarantee from us. Nobody has to ask where the permit is.
Trusted Brands We Service in Pomona
We build with the materials and platforms Pomona homeowners are already researching. For conventional builds, we use James Hardie siding and Tuff Shed-style structures where the budget calls for them. For prefab and modular projects, we’re fluent with Abodu, Cover, and Dvele, and we can match the right platform to your lot dimensions, access restrictions, and budget. We do not push one system on every house. A narrow Pomona lot with tight alley access might be better served by a panelized build than a fully prefabricated module. We’ll tell you which one makes sense and why, in writing, before you commit.
Common ADU Builders Problems We See in Pomona Homes
- Undersized sewer laterals. Older Pomona tracts were built with clay pipe meant for a single bathroom. Adding an ADU means a kitchen sink, shower, and toilet on a line never sized for it, and the city will require the lateral upsized before final inspection.
- Existing garage slabs that fail code. Many 1920s to 1950s garages have slabs that are cracked, sloped, or below finish grade. Current California ADU code requires a level, moisture-managed floor, so the slab often gets cut out and replaced.
- Electrical service that cannot carry the load. A 60-amp panel from a mid-century house will not support a second dwelling with a mini-split, kitchen appliances, and laundry. Pomona’s older housing stock means panel upgrades are common scope on ADU work we quote.
- Setback and fire access problems on narrow lots. Homes near Pomona’s downtown core sit on narrow lots where the standard 4-foot side setback leaves no room for an ADU. A setback variance or a revised site plan is often the only path, and it needs to be identified before the permit application goes in.
Pricing for ADU Builders in Pomona, CA
Here are the ranges we quote most often in Pomona. A garage conversion typically runs $120,000 to $190,000 before permit fees. A new detached backyard ADU runs $200,000 to $340,000 depending on size and site work. A junior ADU inside the existing house runs $70,000 to $120,000. What moves the number is not the floor plan; it is the slab condition, sewer lateral size, electrical panel capacity, and whether the lot needs a setback variance or tree removal. We hand you a written line-item price before any work starts, and the number on your final invoice matches the number you approved on day one. Call (361) 315-4177 for a free estimate and a real number you can plan against.
We Also Serve Cities Near Pomona
Our crews cover Pomona and the surrounding communities, including Diamond Bar, Montclair, Chino Hills, and Claremont. If you are in one of those cities and need ADU Builders, the same written pricing, background-checked crews, and one-year guarantee apply. For Pomona work specifically, you can see more about our local coverage ADU Builders in Pomona or call us directly.
Serving Pomona, CA - Our Local Coverage Area
We’re based in the Pomona 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 Builders in Pomona
Yes, in most cases. The garage must meet California ADU code for ceiling height, slab condition, and sewer lateral capacity, and Pomona’s plan check will require verification that the existing alley or driveway access supports the converted use. Older garages built on the 1920s-1950s grid often need a new slab and a lateral upsized before the project clears. Call (361) 315-4177 and we will walk the garage with you and tell you what the scope is before you commit to a number.
Plan for four to eight weeks in plan check and permitting, then three to six months of construction depending on the scope. Detached builds take longer than garage conversions, and utility upgrades or setback variances add time to the front end. We will give you a written schedule with your price, and we build to that calendar.
The things that change price are almost always the things that were never scoped before the contract was signed. In Pomona, that means a cracked garage slab, an undersized sewer lateral, an electrical panel that cannot carry the load, or a setback variance the original bid ignored. We scope all of that before we price, which is why our number is a contract, not a guess. If site conditions are genuinely different from what the written scope shows, we bring it to you with a written change order before any extra work starts.
Yes. We build detached backyard ADUs, garage conversions, junior ADUs, and custom room additions throughout Pomona. Our crews have converted 1940s garages near Lincoln Park, run new sewer laterals at the alley, poured new slabs, and built detached units on lots with mature tree coverage. Call (361) 315-4177 and tell us what you are working with. We will tell you which path costs less and why.
We use James Hardie siding for conventional builds, and we work with Abodu, Cover, and Dvele for prefab and modular projects. The right choice depends on your lot access, budget, and how fast you want the unit in place. We will match the build method to your Pomona lot instead of forcing one system onto every project. Estimates are free, and the price goes in writing before anything gets built.
Ready to get a real number for your Pomona ADU? Call (361) 315-4177 and ask for Reed Calloway. We will come out, look at your lot, and hand you a written price you can hold us to.
Written by Reed Calloway, Owner at Fielding ADU Builders, coordinating Pomona ADU construction through the Garrison Partners family since 2006.
