We believe in showing our work. Here is exactly how your $149 report is built — every data source, every calculation, every limitation.
Get Your Report →The automated pipeline
The same rigorous process runs on every report. No shortcuts, no manual overrides — just consistent, data-backed analysis delivered fast.
Your report is built from six independent data checks. Each layer runs automatically against your property address. Here is what each one does and where the data comes from.
We cross-reference your address against California ADU law minimum lot thresholds using user-provided lot size and zoning. If not provided at checkout, your report shows exactly where to find them free in under 2 minutes — county assessor and city GIS portal links included.
Our engine uses the city entered with your address and the county returned when we geocode it, and applies California's ADU statutes (Gov. Code §§66310–66342) as the baseline. As of October 2026, ADUVerify looks up the zoning code automatically for addresses in Los Angeles, Oakland, Sacramento, Fresno, San Francisco, Santa Clara, Cupertino, Beverly Hills, West Hollywood, Pasadena, Torrance, Long Beach, Malibu, Santa Monica and unincorporated Los Angeles County. It is not currently available for San Diego, San Jose or Orange County. The lookup is chosen by the address's mailing city, so an address whose mailing city differs from the city or county area it's actually in may not receive a zoning code.
We query three publicly available government databases to flag environmental risk factors that could affect your permitting process or construction costs.
We calculate your Build Envelope — the area of your lot where an ADU can legally be placed. This is determined by rear setbacks (typically 4 feet under California state law), side setbacks (typically 4 feet), height limits (typically 16 feet for single-story detached ADUs), and utility easement locations where known. Most ADUs connect to the property's existing utilities. A new detached ADU can be charged a connection fee — confirm with your utility.
We use RentCast’s rental market statistics for your ZIP code: the average asking rent of active one-bedroom listings, the lowest and highest of them, and how many there were. Return figures (gross yield, net cap rate and payback) are computed from that rent and an assumed $250,000 build cost, and are shown only for a Likely or Possibly Feasible result with at least 3 one-bedroom listings.
Our analysis engine synthesizes findings from all six layers into a single Feasibility Verdict. The zoning check decides the verdict. If the zoning category is residential — from the city's zoning table, or recognised by its name — the report can say Likely Feasible or Possibly Feasible; otherwise it says Zoning category not determined. The data completeness score can only lower that verdict (below 50 it reads Requires Further Review), and a zoning code recognised only by its name, or entered by you, is capped at Possibly Feasible. A flood or high fire-hazard finding earns no points on its card, so it can lower the verdict but never raises it. Unit potential is stated as what may be possible, subject to the city's review.
Every report includes a data completeness score (0–100) and a band — Strong, Good, Moderate or Limited — alongside the verdict.
The score adds up seven checks: location (10 points), county (10), a rent estimate (20), flood (15), fire hazard (15), zoning code (up to 15) and lot size (15). A flood or high fire-hazard finding, or a check that could not be completed, earns no points for that check. Strong is 85–100, Good 70–84, Moderate 50–69, Limited 0–49. The score counts which checks returned data and whether the flood and fire checks came back clear; it can lower the verdict but never raises it.
How we calculate build cost, monthly rent, cap rate, and payback period.
Regional construction benchmarks for California, updated periodically:
Based on RentCast market data for your ZIP code, adjusted for estimated ADU size (typically 400–800 sq ft). Projections reflect current market rates — not guaranteed future income.
Cap rate = (Annual gross rent − 10% operating expenses) ÷ estimated build cost.
Payback period = estimated build cost ÷ annual net rental income. Simple payback — does not account for property value appreciation, financing costs, or tax implications.
Important: All cost estimates are preliminary ranges based on regional benchmarks. Actual costs vary based on site conditions, finishes, permit fees, utility connection costs, and contractor availability. Always obtain 2–3 contractor bids before committing to a project.
Every data point in your report comes from a named, verifiable source. Here is the complete list.
| Data Source | Used For | Update Frequency |
|---|---|---|
| User-provided inputs | Lot size and zoning code (optional at checkout) | Provided at time of order |
| FEMA NFIP Flood Maps | Special Flood Hazard Area designation | Updated continuously |
| CAL FIRE FHSZ Maps | Fire hazard severity zone classification | Updated annually |
| California HCD | State ADU law compliance baseline | Updated with legislation |
| RentCast | Rental market statistics by ZIP code | Updated monthly |
Being transparent about limitations builds more trust than hiding them. Here is what our automated system cannot reliably evaluate.
CC&Rs and HOA restrictions are not in public databases. Verify with your title company or HOA directly before proceeding.
Whether your existing sewer, water, and electrical service can support an additional unit requires a site assessment by a licensed engineer.
Foundation requirements depend on soil type and slope, which require a physical site survey. Hillside lots are particularly variable.
Properties in historic districts may face additional design review requirements not captured in standard zoning data.
Local zoning changes may not be reflected immediately. Reports reflect data available at time of generation. Always verify current rules with your local planning department.
No automated tool can guarantee permit approval. Your report identifies feasibility — your local planning department makes the final determination.
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Get Your Report →Preliminary assessment only. Not a zoning determination or legal opinion.