ADU in Anaheim, CA
Junior ADU & Interior Conversion in Anaheim typically runs $85,000-$165,000 all-in, drawings through final inspection, while ADU Site Prep & Utilities adds $15,000-$75,000 depending on whether your 1950s ranch needs a 200-amp panel upgrade or sewer lateral replacement. We’re Ellery ADU Studio, and we handle both the design-build contract and the permit set under one written price. Call (657) 233-9738 to schedule your free estimate.
Why Anaheim Homes Are Different
West Anaheim and Central Anaheim are packed with 1950s-1960s postwar ranch-style tract homes on 6,000-8,000 sq ft lots. The lots are large enough for a detached ADU under California’s streamlined rules, but the original 100-amp electrical panels are not - most must be upgraded before the city will issue an ADU permit. In the Anaheim Colony Historic District, California’s by-right ADU law collides with local historic preservation guidelines, adding a design review layer that flatland neighborhoods don’t face. Anaheim Hills parcels fall within Very High Fire Hazard Severity Zones, where CAL FIRE requires ember-resistant vents, fire-resistant exterior assemblies, and residential sprinklers in new ADUs. And the Disneyland proximity creates a recurring compliance trap: homeowners near Harbor Boulevard and Katella Avenue often finance projects around short-term rental income that Anaheim’s STR ordinance restricts in residential zones. We address this in the first site visit, before permit fees are ever discussed.
Our Main Anaheim Services
These are the three services Anaheim homeowners call about most.
ADU Design & Permitting in Anaheim
We produce the full permit set - site plan, floor plan, elevations, structural calcs, Title 24 energy compliance - as the core deliverable, not an afterthought. For Anaheim Colony Historic District properties, we reconcile state streamlining with local preservation guidelines before the city review begins. ADU Design & Permitting in Anaheim

Garage Conversion ADU in Anaheim
Most Anaheim conversions start with a 4-inch slab from the 1950s and a roofline that needs structural verification. We assess the existing foundation, wall framing, and utility capacity in the first site visit, then quote a single written price for drawings through final inspection. Garage Conversion ADU in Anaheim

New Detached ADU in Anaheim
Detached ADUs on Anaheim’s standard 6,000-8,000 sq ft lots must clear setback rules and, in Anaheim Hills, CAL FIRE ember-resistant construction requirements. We coordinate the prefab or stick-built structure, foundation, and utility tie-ins under one contract. New Detached ADU in Anaheim

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.
Junior ADU & Interior Conversion in Anaheim

Junior ADU & Interior Conversion in Anaheim solves a specific problem: homeowners who want rental income or multigenerational space but lack the budget or lot geometry for a detached unit. The 1950s-1960s ranch stock in West Anaheim and Central Anaheim is ideal for this - generous floor plates, simple rooflines, and existing utility access - though the original 100-amp panels almost always require upgrade. We handle the full Junior ADU & Interior Conversion design-build process, from feasibility study through final inspection, at the written price quoted before work starts.
Room-to-ADU Conversion
Signs you need it
You have an underused bedroom wing, a former den, or a side room with separate exterior access that could become a self-contained unit.
What it costs in Anaheim
Room-to-ADU conversion in Anaheim typically runs $85,000-$140,000 all-in, including the electrical panel upgrade that most 1950s-1960s homes require.
How we do it
We verify ceiling height meets 7’6″ minimum, add a kitchenette and full bath within the existing envelope, run a separate meter or subpanel, and produce the permit set for Anaheim’s one-stop permit center.
Interior JADU
Signs you need it
You want rental income but your lot is at minimum setback, your budget is under $100,000, or you need to keep the main house as your primary residence.
What it costs in Anaheim
Interior JADU projects in Anaheim typically range $75,000-$125,000, with the lower end achievable when the existing bathroom and kitchen plumbing stack are adjacent to the proposed unit.
How we do it
We identify the smallest code-compliant footprint, add an efficiency kitchen and 3/4 bath, create a separate entrance, and document the owner-occupancy requirement in the permit set for Anaheim’s planning division.
What Junior ADU & Interior Conversion Costs in Anaheim
| Item | Typical range in Anaheim |
|---|---|
| Room-to-ADU conversion (all-in) | $85,000-$140,000 |
| Interior JADU (all-in) | $75,000-$125,000 |
| Electrical panel upgrade (required on most) | $4,500-$8,500 |
Does a Junior ADU need a separate meter in Anaheim?
No - a Junior ADU can share the main home’s electrical meter and water service, though many homeowners opt for submetering to track tenant usage. Call (657) 233-9738 for an exact quote - estimates are free.
Can I convert any room in my Anaheim house?
No - the room must have minimum 7’6″ ceiling height, natural light per code, and access to a bathroom; we verify all three in our feasibility study before quoting. Call (657) 233-9738 for an exact quote - estimates are free.
ADU Site Prep & Utilities in Anaheim

ADU Site Prep & Utilities in Anaheim addresses the hidden infrastructure that must be resolved before the city will issue an ADU permit. The 1950s-1960s housing stock here was built for single-family load, not secondary units, so the electrical, sewer, and gas systems are almost always undersized. In Anaheim Hills, fire hazard zone requirements add ember-resistant venting and sprinkler infrastructure that flatland projects don’t need. We coordinate all utility work and site preparation under the same ADU Site Prep & Utilities contract, with one written price and one point of accountability.
Electrical Panel Upgrade
Signs you need it
Your main panel is rated 100 amps, has no open breaker slots, or still uses a fuse box - all common in Anaheim’s postwar ranch stock.
What it costs in Anaheim
Electrical panel upgrade in Anaheim typically runs $4,500-$8,500, including the new 200-amp panel, permit, and Anaheim Public Utilities coordination.
How we do it
We size the load for main house plus ADU, coordinate the Anaheim Public Utilities service upgrade, install the new panel, and document the final for the city’s electrical inspector.
Plumbing Lateral
Signs you need it
Your home has original cast iron or clay sewer pipe, frequent backups, or the ADU location is more than 30 feet from the main sewer line.
What it costs in Anaheim
Plumbing lateral replacement or extension in Anaheim typically ranges $6,500-$15,000, with trenchless methods at the higher end when landscaping or hardscape must be preserved.
How we do it
We video-inspect the existing line, specify replacement or extension to code depth, coordinate with Anaheim Public Works for street connection, and pressure-test before backfill.
What ADU Site Prep & Utilities Costs in Anaheim
| Item | Typical range in Anaheim |
|---|---|
| Electrical panel upgrade | $4,500-$8,500 |
| Plumbing lateral replacement/extension | $6,500-$15,000 |
| Gas line extension | $3,500-$7,500 |
Will Anaheim Public Utilities require a separate meter for my ADU?
Detached ADUs require separate electric and water meters; Junior ADUs and interior conversions can share existing service with submetering. Call (657) 233-9738 for an exact quote - estimates are free.
How long does site prep take before construction starts?
Utility coordination in Anaheim typically adds 4-8 weeks before construction begins, with Anaheim Public Utilities and Public Works scheduling the longest lead times. Call (657) 233-9738 for an exact quote - estimates are free.
Brands We Service in Anaheim
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, and James Hardie within our single-contract design-build model. Parts and assemblies are stocked through regional distributors with 48-hour turnaround to Anaheim job sites. our brands
Pricing for ADU in Anaheim, CA

| Service | Typical range in Anaheim |
|---|---|
| Junior ADU & Interior Conversion (all-in) | $75,000-$165,000 |
| Room-to-ADU conversion | $85,000-$140,000 |
| Interior JADU | $75,000-$125,000 |
| Electrical panel upgrade | $4,500-$8,500 |
| Plumbing lateral replacement/extension | $6,500-$15,000 |
| Gas line extension | $3,500-$7,500 |
| Foundation & grading (detached ADU) | $12,000-$28,000 |
| Landscaping & hardscape restoration | $5,000-$18,000 |
Price drivers in Anaheim include the 100-amp panel upgrades common in 1950s-1960s stock, Anaheim Hills fire hazard zone requirements, and historic district design review. Under Haven Standard Clause 1, your written price is locked at signing - no door-side upsells, no scope creep.
Neighborhoods We Serve in Anaheim
We work across Anaheim’s full residential footprint, from the flatland ranch tracts to the hillside zones. Scheduling and dispatch are coordinated from our Los Angeles office; crews serve Anaheim locally with next-day site visits typically available.
- West Anaheim
- Central Anaheim
- Anaheim Hills
- Anaheim Colony Historic District
- Southeast Anaheim
Service Area - Cities Near Anaheim

Our crews work throughout central Orange County, including Garden Grove, CA, Westminster, CA, Orange, CA, and Santa Ana, CA. Each city has its own permit timeline, utility provider, and zoning quirks; we adjust the permit set and project schedule accordingly.
Serving Anaheim, CA - Our Local Coverage Area
We’re based in the Anaheim 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 in Anaheim

Anaheim’s one-stop permit center typically processes complete ADU applications in 60-90 days for standard projects; Anaheim Colony Historic District or Anaheim Hills fire zone projects add 30-60 days for additional review layers.
Anaheim’s STR ordinance restricts new short-term rental permits in residential zones, so we advise clients to underwrite projects on long-term tenancy economics, not Airbnb projections - this is a compliance trap we address in the first site visit.
We pull all permits as part of our single-contract scope - building, electrical, plumbing, and fire sprinkler where required - and we pass all inspections before final sign-off. The permit cost is itemized in your written quote, not hidden.
Call (657) 233-9738 to schedule your free estimate. Every project starts with a written price, a documented photo record, and the 365-Day Done Right Promise - in writing, before any work begins.
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 Anaheim Customers Say
"They walked us through setbacks and utility capacity before we paid anything, and told us one of our two options was not going to get approved."
- Mireille T."Garage conversion finished on the drawings and close to the schedule. They were honest that the sewer connection was the unknown, and it was."
- Arjun D."Detached unit in the back garden. Good design, good build quality, and the cost changes were documented and agreed in advance."
- Stefan B.