A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Fillmore, CA
An ADU in Fillmore is a different project than one in Oxnard or Thousand Oaks. The lots run larger here, the homes span from 1940s bungalows near downtown to 1970s ranch-style tracts, and every permit carries an extra layer: wildfire safety. Benson ADU Ventura builds detached ADUs, garage conversions, and home additions that meet Ventura County’s WUI (wildland-urban interface) codes, and we put the full price in writing before anyone picks up a hammer. Call (350) 207-2506 to talk through your lot.
Why Fillmore Homes Are Different
Fillmore sits in the Heritage Valley, surrounded by citrus groves and the Sespe foothills, and a lot of its housing stock predates modern building codes by decades. The older grid near downtown is mostly single-story stucco and wood-frame homes from the 1940s and 50s, with tight side yards and aging utility lines. The newer tracts fan out toward El Dorado and River Parkway with larger ranch-style homes on quarter-acre lots and up.
What this means for an ADU project: the older lots often trigger a sewer lateral inspection. Many still connect to the original clay pipes, and adding a bathroom can force a $2,000 to $5,000 lateral replacement before the ADU gets its certificate of occupancy. Fillmore is not alone in this, but it is more common here than in newer Ventura County cities because of the housing age.
Then there is fire. Fillmore sits in a wildland-urban interface zone, which means the fire marshal is part of the review. ADUs need non-combustible siding, tempered glass, and screened vents. The summers are hot and dry, and Santa Ana winds push fire downhill fast, so the code is not optional. A prefab ADU with steel or cement-board cladding can be the fastest path through plan check because it arrives with fire-rated assemblies already documented.
Our Main Fillmore Services
Fillmore homeowners call us about three things most often: building a detached ADU in the back yard, adding square footage onto an existing house, and converting a garage or bonus room into living space. Each has its own dedicated page with local pricing and details.
ADU Builders in Fillmore
Fillmore’s lot sizes make detached ADUs genuinely viable – many back yards have enough depth for an 800 to 1,200 square foot unit without touching the primary home. We build both site-built and prefab ADUs here, and the prefab route has a real advantage in Fillmore: the panels arrive factory-built with the ember-resistant assemblies already tested, which shortens the fire-review portion of plan check. See the full breakdown for ADU Builders in Fillmore.
Home Addition Contractor in Fillmore
A home addition in Fillmore usually means going outward on a ranch-style lot rather than up, since most of the newer homes are single-story. The cost drivers here are utility trenching across longer runs and the fire-rated exterior details. We handle both stick-frame additions and hybrid prefab panel additions, with a written price before work starts. Details are on the Home Addition Contractor in Fillmore page.
Room Addition Contractor in Fillmore
Room additions in Fillmore are often about aging in place or adding a home office to one of the older bungalows. The tighter lots near downtown mean the addition has to work within existing setback lines, which makes a prefab panel system a practical fit since the panels can be craned over a small yard. See the local pricing and approach on the Room Addition Contractor in Fillmore 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 Fillmore
We build with prefab systems from Cover, Dvele, and Boxabl, plus James Hardie cladding for site-built ADUs. Parts and panels are ordered to spec for each Fillmore job, with lead times quoted up front. See our brands for the full list.
Pricing for ADU Company in Fillmore, CA
| Service | Typical range in Fillmore |
|---|---|
| Detached ADU (prefab, 400 – 800 sq ft) | $180,000 – $320,000 |
| Detached ADU (site-built, 800 – 1,200 sq ft) | $280,000 – $450,000 |
| Garage conversion ADU | $120,000 – $190,000 |
| JADU (junior ADU, 500 sq ft or less) | $90,000 – $150,000 |
| Home addition (400 – 800 sq ft) | $160,000 – $320,000 |
| Room addition (300 – 500 sq ft) | $110,000 – $210,000 |
| Utility trenching (per linear foot, Fillmore range) | $60 – $120 |
| Sewer lateral replacement (if required) | $2,000 – $5,000 |
| WUI-compliant cladding upgrade | $12,000 – $28,000 |
Fillmore prices get pushed up by two things we see repeatedly: long utility trench runs from the street to the back of a deep lot, and sewer lateral replacements on the older grid. That is exactly why we give every Fillmore homeowner a written price before any work starts, so a lateral inspection does not become a surprise invoice.
Neighborhoods We Serve in Fillmore
We work across all of Fillmore, from the historic grid near Central Avenue to the newer tracts by River Parkway and the ranchette lots in the surrounding citrus belt. Typical scheduling for an estimate visit is within a few business days depending on week:
- Downtown Fillmore (Central Ave corridor)
- El Dorado Estates
- River Parkway area
- Heritage Valley ranchette lots
- Sespe foothill parcels
Service Area – Cities Near Fillmore
Benson ADU Ventura serves Fillmore and the surrounding Heritage Valley communities. If your property is nearby, we also cover Moorpark, CA, Santa Paula, CA, Somis, CA, and Simi Valley, CA.
Serving Fillmore, CA - Our Local Coverage Area
We’re based in the Fillmore 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 Fillmore
Our scheduling for Fillmore estimates is typically within a few business days. The timeline to construction depends on plan check and permits, which are city-specific. Call (350) 207-2506 and we’ll give you a realistic schedule for your lot.
Yes, if the home is in a wildland-urban interface zone. Fillmore’s fire marshal reviews each project for WUI compliance, which usually means non-combustible siding, tempered glass, and screened vents. Our prefab ADUs from Cover and Dvele arrive with fire-rated assemblies already documented.
Yes. We pull all permits and coordinate inspections with the city of Fillmore and Ventura County. Every project carries our 365-Day Done Right Promise in writing, and the permit process is handled from submittal to final sign-off. Call (350) 207-2506 for a free estimate on your ADU or home addition.
Ready to talk about an ADU or addition in Fillmore? Call (350) 207-2506 for a written estimate. Troy Eastman leads our team, and no Fillmore project starts without a confirmed price in writing.
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 Fillmore Customers Say
"Garage conversion into a guest suite. I could see the permit status in the app, which made it painless."
- Rick F."Fixed quote and clear change orders approved by text."
- Trina M."Room addition off the kitchen. Framing, drywall, and paint all done well."
- Wade L.
