Golden State ADUs designs, permits, and builds accessory dwelling units (ADUs) for Chico homeowners, with architectural design, structural and civil engineering, permitting, and construction all under one contract. If you want one accountable ADU builder from first site visit through certificate of occupancy, that is what we do. We specialize in ADUs and build nothing else.
We know a six-figure build decision deserves caution, so here is the short version: we are licensed and bonded (LIS. #1125656), trusted by 100+ happy customers, and every project carries a 10-year structural integrity warranty and a 1-year fit-and-finish warranty. Your ADU can be detached in the backyard or attached to the house, designed to fit your life, and a well-built unit adds meaningful long-term property value.
Chico’s older grid neighborhoods, with their Craftsman homes, bungalows, ranch houses, and mature tree canopy, reward careful site planning. One detail worth knowing early: Chico Municipal Code allows an ADU or JADU to be rented only for terms of 30 or more consecutive days.
Start with a free 1-hour project walkthrough. One visit tells you whether your Chico lot works, what it will likely cost, and what the City will allow. Call (916) 909-2387 to book it.
Our ADU Construction Services in Chico
We handle every phase of your Chico ADU in-house, from concept to completion, which means no outside architect, engineer, or separate builder for our clients to coordinate. Our in-house design and engineering arm, Golden State Design & Engineering, supplies architectural design, structural engineering, and civil engineering, so one team owns the drawings, the permit corrections, and the field work. You can see the full breakdown on our ADU services page.
Detached ADUs and Backyard Bungalows
Detached ADUs, sometimes called backyard cottages or granny flats, are standalone units built in the rear yard on the same lot as your primary residence. They are the most common choice for rental income, guests, or a private workspace. Chico’s pre-approved catalog includes one-story plans at 496, 599, and 749 square feet, a useful reference point for what fits comfortably on a typical lot here.
Attached ADUs and Garage Conversions
When the yard is tight, we build attached ADUs that share a wall with the main house, convert an existing garage into a complete living space, or convert a basement into an independent unit. Chico’s pre-approved catalog even includes a 599-square-foot living area over a garage, an option worth exploring when ground-level space is limited.
Custom ADUs, Tiny Homes and Studios
Not every property suits a catalog plan, so we design custom ADUs from scratch: studios, tiny homes, one-bedroom, two-bedroom, and three-bedroom layouts. Most ADUs land between roughly 250 and 750 square feet. We size the plan to the lot rather than forcing the lot to accept a plan, and we select materials that hold up to Chico summers.
Retirement and Multigenerational ADUs
A retirement ADU keeps a parent close without putting everyone under one roof, and it leaves your family with a unit that outlasts the arrangement and becomes part of the property’s legacy. Chico’s pre-approved catalog includes reversed plans and accessible universal-design variations, and we design to those same principles: single-level entry, wider doorways, and bathrooms that work for decades.
Design, Engineering and Permitting Handled In-House
Design, engineering, permitting, and compliance are done for you. We produce fully compliant plans, prepare the forms, and manage the submittal. That includes the parts people forget: utility connections, which differ depending on whether your property is on septic or municipal sewer, plus drainage, electrical service capacity, and the site plan the City needs before anything gets reviewed.
Why Chico Homeowners Choose Golden State ADUs
ADUs are all we do. We are not a remodeling company that adds ADUs to a service list, which is why one team owns the job from feasibility through certificate of occupancy with no handoff where accountability disappears.
The proof points are specific. We are licensed and bonded under LIS. #1125656. Every project includes a 10-year structural integrity warranty and a 1-year fit-and-finish warranty. We have been trusted by 100+ happy customers and carry 18 Google reviews. Responsiveness is a pillar of how we work: we answer calls and emails quickly and send regular project updates rather than making you chase them.
On budget, we are direct. We analyze your budget upfront, write a detailed contract listing estimated costs and components, and use value engineering to protect the things that matter when numbers move. We practice fair and transparent pricing with no hidden costs, and we do not publish a fixed price, because no honest ADU builder can quote your site before seeing it.
About the distance. Our office is in Roseville, roughly 83 to 84 driving miles from Chico, about an hour and a half without stops. That is a routine drive for scheduled walkthroughs, on-site project management, inspection coordination, and specialized trade oversight. We manage these construction projects directly rather than leaving them to whoever shows up.
Vet any California ADU builder the same way you would vet contractors for any major build: confirm the license through the CSLB, ask for proof of liability insurance and workers’ compensation, request the project portfolio and references, and check that the builder has real knowledge of your city’s regulations. Also know that California limits a contractor’s upfront deposit to 10% of the contract or $1,000, whichever is less.
Ready to compare us properly? Book a consultation and ask us anything on that list.
What an ADU Adds: Property Value and Additional Income
Most Chico homeowners who call us seek one of three outcomes: additional income from a long-term rental, a place for family nearby, or a flexible unit that makes the main house work better and improves the living experience on the property. A permitted, well-built ADU also contributes property value, because it is finished square footage with its own kitchen, bath, and entry. We do not project returns or promise a rent figure. Chico’s long-term rental market and your finish choices decide that.
A few benefits are worth being realistic about. ADUs are part of California’s answer to affordable housing, which is why the state keeps loosening the rules. Rentals here must run 30 days or longer, so plan for stable tenants rather than nightly stays. And new square footage is generally assessed, so ask your county assessor and tax professionals how property taxes would change before you set a budget. These are long-horizon investments, and we treat them that way.
How Your ADU Project Works, Step by Step
Your ADU journey follows four phases, and we tell you exactly where you stand in the building process at each one.
- Free 1-hour walkthrough and feasibility read. We look at property boundaries, setbacks, mature trees, alley access, utility locations, drainage patterns, flood designation, and fire access, then tell you plainly what your lot supports.
- Design and budget analysis. We define scope, allowances, and exclusions, apply value engineering where it helps, and put it into a detailed contract that lists estimated costs and components. If you are collecting proposals, compare them only when each one is priced from identical plans and specifications. Otherwise you are comparing assumptions, not bids.
- Permitting and compliance. We prepare the submittal, file it, handle corrections, and secure the building permit. California requires local agencies to act on a complete ADU permit application within 60 days, and we build the package to meet state ADU law so review moves rather than stalls.
- Construction, inspections, and closeout. On-site project management, inspection coordination, and regular owner updates over the course of the build through final sign-off.
Typical timing: 3 to 5 months for design and permitting, then 3 to 4 months of construction, with many ADU builds landing in the 4 to 6 month construction range depending on complexity. Those are typical ranges, not guarantees, and we tell you early if your site points toward the longer end.
What Building an Accessory Dwelling Unit in Chico Actually Involves
Building an ADU in Chico means satisfying City-specific site standards that go well beyond state ADU law. State rules apply the same whether your parcel sits in San Jose, elsewhere in the Bay Area, or here in the North Valley, but cities differ sharply in how they review and condition a project. Permits for properties inside city limits run through the City of Chico Community Development Department, Building Division, at 411 Main Street, 2nd Floor, and zoning questions go to the Planning Division at the same address.
One honest note first: be aware that a Chico mailing address does not always mean City of Chico jurisdiction. We confirm the parcel’s governing agency before we tell you which rules apply.
Your neighborhood shapes the plan. The Avenues contains many traditional residences built between 1900 and 1910, with the East and West Avenues holding modest homes on smaller lots while Mansion Park has larger houses on larger lots. South Campus, which Chico State defines as the area south of West Second Street between Broadway/Main and the Union Pacific tracks, mixes 19th-century homes, fraternity and sorority houses, and smaller apartments. More than 73% of Chapman/Mulberry housing identified in the adopted neighborhood plan predates 1950. The Filbert and Palmetto avenues areas are predominantly post-World War II ranch development. Newer north and east Chico neighborhoods have less mature vegetation, less rectangular street grid, and a mix of acreage homes, small-lot infill, and low-density stucco or panel-sided houses.
Chico’s local code provisions we design around:
- If your site is served by an alley, the ADU must take its primary vehicle access from that alley.
- An alley-adjacent ADU needs at least one shielded, downward-directed security light illuminating the alleyway.
- A new driveway running behind the main house must use permeable all-weather material, two tire strips, or another design that keeps runoff onsite.
- An ADU not adjacent to an alley must be placed so every side sits within 150 feet of unobstructed access from the street frontage for fire protection.
- Outdoor trash and recycling storage must be screened and on an all-weather surface.
Flood and fire are parcel-level questions. Properties in flood zones A, AO, AE, OR, or AH may require additional design plus pre- and post-construction Flood Elevation Certificates. A portion of northeast Chico is designated a very high fire-hazard severity zone, though that designation does not cover all of Chico, which matters because the city sits at the transition from flat Sacramento Valley land in the west to Sierra foothill terrain in the east.
Heat and rain drive design and scheduling. NOAA’s 1991 to 2020 Chico normals show a July daily high of 95.2°F and 94.3°F in August, so we size HVAC properly, tighten the envelope, and place windows with shade in mind. With 27.39 inches of annual precipitation concentrated in the cool season, we schedule excavation and exterior work for the dry months and plan drainage and erosion control for the wet ones.
State law has also opened things up: minimum lot size requirements for ADUs are gone, setback rules were reduced, Chico’s standards allow 4-foot minimum side and rear setbacks, and an ADU under 800 square feet cannot be denied on floor area ratio grounds. Permitting has been streamlined since 2020. The site-level details are still where projects succeed or stall, which is why we start there. Talk to us about your parcel.
Frequently Asked Questions
How much does an ADU cost to build in Chico?
It varies by size, site conditions, utility work, and finishes. Nationally, ADU construction runs from roughly $30,000 for simple conversions to over $300,000 for larger custom builds, and California construction commonly falls between $125 and $300-plus per square foot. Chasing the lowest number rarely produces affordable construction once corrections and change orders arrive. We provide a site-specific estimate with itemized costs and components rather than a published fixed price.
How long does ADU permitting take in Chico?
California requires local agencies to act on a complete ADU permit application within 60 days, and our typical design and permitting phase runs 3 to 5 months, followed by 3 to 4 months of construction. The City of Chico Building Division at 411 Main Street handles permits, and using the City’s pre-approved plans can reduce the amount of original plan development required. Treat these as typical ranges, not guarantees.
What is the biggest ADU you can build?
State law protects ADUs under 800 square feet from denial on floor area ratio grounds, and Chico’s pre-approved one-story plans top out at 749 square feet. Larger units are often possible but fall under additional local standards. We confirm the real ceiling for your specific parcel before design starts.
What is a JADU versus an ADU?
A junior ADU is a smaller unit created within the walls of the existing home, while an ADU can be detached, attached, or converted from a garage or basement. Both are legitimate paths depending on your layout and budget. Chico applies the same 30-day minimum rental term to each.
Can I rent my Chico ADU short-term?
No. Chico Municipal Code allows ADU and JADU rentals only for terms of 30 or more consecutive days. That still leaves long-term rental to offset a mortgage, housing a family member nearby, or a dedicated guest and work space. Confirm current rules with the City of Chico Planning Division at 411 Main Street.
Do I need fire sprinklers in a Chico ADU?
Chico does not require sprinklers in an ADU when sprinklers are not required in the main residence. A portion of northeast Chico carries a very high fire-hazard severity designation, which can change requirements, and that designation is parcel-specific. We verify your parcel with the City before design assumptions are locked.
Start Your Chico ADU With a Free Walkthrough
One hour on your property gets you three straight answers: whether your lot works, a realistic budget range for what you have in mind, and what Chico will and won’t allow on that parcel. Bring every ADU question with you. No obligation, no pressure, just clarity from a team that builds ADUs and nothing else.
Let’s connect. Call us at (916) 909-2387 or email office@gsadus.com, or send the details through our contact page. Our office is at 1001 Enterprise Way #100 in Roseville, about an hour and a half up Highway 99 from Chico, a drive we make for scheduled site visits and project oversight.
Golden State ADUs provides design, permitting, and construction throughout California, including Chico and the greater Sacramento region.
