Instant ADU QuoteReal Pricing in 2 Minutes — Ventura County & LA 2026

Use the free online calculator on this page. Answer 5 questions about ADU type (detached, attached, garage conversion, junior), size, finish tier, and location. Get a real Ventura County or LA County ADU price range in under 2 minutes.

ADU construction in Ventura County and LA County: detached ADUs run $200,000–$350,000, attached ADUs $150,000–$250,000, garage conversions $90,000–$150,000, and junior ADUs $60,000–$100,000. Final cost depends on size, finishes, site conditions, and city permit fees.

Our ADU quote uses real project data from hundreds of ADUs built across Ventura County and LA County. Quotes are accurate within 10–15% for typical lots. Sloped sites, utility connections (sewer lateral, electrical panel upgrade), and historic district requirements can shift the final contract number.

Most ADUs take 3–6 months to build once permits are approved. Permitting adds 2–4 months depending on city (Simi Valley and Thousand Oaks process faster than LA). Garage conversions are quicker (3–4 months). Detached ADUs with foundations take longer (5–7 months).

Yes. All ADU types — detached, attached, garage conversion, junior ADU — require building permits. Requirements vary by city. We handle the full permit process: plan preparation, submission, plan check revisions, and inspections.

Yes. California state law allows homeowners to rent ADUs long-term without an owner-occupancy requirement. Short-term rentals (Airbnb) depend on city rules — some Ventura County cities permit them, others restrict to long-term only. We can tell you what your specific city allows.

California law allows detached ADUs up to 1,200 sq ft on most residential lots. Attached ADUs are capped at 50% of the main home or 1,200 sq ft (whichever is less). Junior ADUs are capped at 500 sq ft. Setbacks typically 4 ft from side/rear property lines.

SB9 (the California HOME Act) allows homeowners to split a single-family lot into two parcels, with up to 2 units per parcel (potentially 4 units on one original lot). Applies to most single-family zones, not in historic districts or fire hazard zones. Each parcel must be at least 1,200 sq ft.

Yes. 100% free, no obligation, no sign-up, no credit card.

Not for our instant online quote. See the price range first, then decide whether to book a free in-person consultation to evaluate your specific lot.

ADU ROI varies — most homeowners see it through rental income ($1,800–$3,500/month in Ventura County for a 1-bedroom) or added resale value ($150K–$250K value add for a well-built detached ADU). Payback periods typically 7–12 years.

Simi Valley, Thousand Oaks, Moorpark, Camarillo, Oxnard, Newbury Park, Oak Park, Agoura Hills, Calabasas, Woodland Hills, West Hills, Sherman Oaks, Encino, Northridge, Santa Clarita, and surrounding cities across Ventura County and Los Angeles County.

The CalHFA ADU Grant Program provides up to $40,000 for pre-development costs (permits, plans, site prep). Eligibility is based on income limits. We can refer you to lenders who process these grants and help you understand eligibility.