How Zonara Determines Permitted Unit Counts: Our Methodology
Zonara determines permitted unit counts by cross-referencing three primary sources: LA County Assessor records (baseline count), LADBS permit history (additions, conversions, ADUs), and zoning/entitlement data (what's allowed by right). When sources conflict, we flag the discrepancy and explain the likely cause in plain language.
Key Takeaways
- Three-source verification: Assessor + LADBS permits + zoning entitlements.
- Every unit count includes provenance — you can see where the number came from.
- Discrepancies are flagged, not hidden. We show the conflict and explain it.
- Permit-based additions (ADUs, conversions) are tracked by permit number and final status.
- Zonara's methodology is deterministic: same inputs produce the same outputs every time.
Want the practical checklist version of this methodology (what to do, in what order, before MLS or escrow)? How to Verify Permitted Units in Los Angeles.
Why Methodology Matters
Unit count is one of the most financially significant data points in multifamily real estate. A duplex valued at $1.2M becomes a triplex valued at $1.6M with one permitted ADU. Getting this number wrong — in either direction — has real consequences for pricing, lending, and legal liability.
Most platforms display whatever the Assessor says. Some show listing agent claims. Neither is reliably accurate. Zonara takes a different approach: we verify from source records and show our work.
The Three-Source Model
Source 1: LA County Assessor
The Assessor's roll provides the baseline unit count. This is what appears on tax records and most listing platforms. It's updated on reassessment — typically at sale or construction completion.
Strength: Broadly available, standardized. Weakness: Can lag years behind actual changes. Misses ADUs, garage conversions, and interior modifications that don't trigger reassessment.
Source 2: LADBS Permit History
We pull the full permit history for every property and parse it for unit-affecting permits. These include new construction, additions, ADU permits (both new-build and conversion), and change-of-use permits.
For each relevant permit, we track the permit number, issue date, scope of work description, and — critically — whether it received a final inspection.
Strength: Legally authoritative. If a permit was issued and finaled, the unit exists in the eyes of the city. Weakness: Permit descriptions can be ambiguous. "Interior remodel" might or might not involve a unit addition. Our parsing logic handles common patterns, with manual review flags for edge cases.
Source 3: Zoning and Entitlements
We cross-check the property's zoning designation against the city's density rules to determine how many units are allowed by right. This provides a ceiling: a property zoned R1 shouldn't have four permitted units (unless a variance or specific plan applies).
Strength: Provides context for whether a permit-based unit count is plausible. Weakness: Zoning changes, specific plans, and density bonuses add complexity. We account for the most common LA zoning designations.
All source data is publicly available. Assessor records: assessor.lacounty.gov. LADBS permits: ladbs.org/services/check-permit-status. Zoning data: ZIMAS (zimas.lacity.org). Zonara automates the retrieval and cross-referencing of these sources.
How We Resolve Conflicts
When the three sources agree, the unit count is straightforward. When they don't, we apply the following logic:
Assessor < Permits. Most common case. Usually means a recently permitted ADU or conversion hasn't been reassessed yet. We report the permit-based count as the "permitted units" figure and note the Assessor discrepancy.
Assessor > Permits. Less common but important. May indicate unpermitted construction that the Assessor counted (e.g., from aerial imagery). We flag this as a potential unpermitted unit — a risk factor for buyers.
Permits > Zoning allows. Could indicate a variance, density bonus, or historical entitlement. We flag it for review rather than assuming an error.
Example Resolution: 2914 Sunset Blvd, Los Angeles Assessor: 4 units LADBS Permits: 5 units (ADU permit #20016-20000-54321, finaled 2023-11-02) Zoning: C2-1VL (commercial, no residential density cap) Resolution: Permitted count = 5. Assessor lag = 1 unit. No zoning conflict.
Deterministic and Reproducible
Zonara's methodology is fully deterministic. Given the same source data, the system produces the same unit count and the same discrepancy flags every time. There's no LLM-based guessing in the unit count pipeline. We use structured parsing rules applied to structured public records.
This matters for compliance, audit trails, and trust. If you run a Zonara report today and again next month (with the same source data), you'll get the same result.
Apply This Methodology (Checklist)
This post explains the evidence hierarchy. For the step-by-step workflow + listing-safe language, see: How to Verify Permitted Units in Los Angeles.