Data Sources

The public datasets and services this platform queries at analysis time, plus what the analysis engine and the AI assistant each cover.

Every feasibility analysis is assembled in real time from public GIS services and regulatory datasets. No human-curated parcel database sits between you and the source data — when you submit an address, the platform queries each provider directly and applies the current California and City of San Diego regulations to what it finds.

Two systems, two scopes

The platform has two independent systems that often get conflated, so it's worth distinguishing them:

The analysis engine — runs the per-pathway unit-count math when you submit an address. It evaluates the broader regulatory stack documented on the Regulations page using the GIS and zoning data sources listed below.
The AI Q&A assistant— answers natural-language questions about San Diego zoning. Its knowledge base is a manually-maintained representation of SDMC Chapter 13, Articles 1, Divisions 4 and 5 (residential and commercial zone rules). On the results page, the assistant also receives a structured summary of your specific analysis — derived from the same Supabase zone tables that drive the calculator — so it can ground answers in your parcel's actual values rather than generic regulatory text.

An AI answer that says “the source material in this tool doesn't cover X” means the assistant's narrower corpus doesn't cover X — the analysis engine may still incorporate that rule. When in doubt, the Regulations page is the canonical inventory of what the engine models.

Parcels, geography, and basemap

Parcel geometry and attributes — SANDAG Regional Data Warehouse
Address geocoding — City of San Diego Web GIS
Ground elevation — U.S. Geological Survey 3DEP Elevation Point Query Service
Alleys, streets, and overhead utility lines — OpenStreetMap contributors
Basemap tiles — © OpenStreetMap contributors © CARTO

Zoning and overlay designations

Zoning, overlays, and regulatory boundaries — City of San Diego Development Services Department
Historic resources and districts — City of San Diego Historical Resources Board

Regulations covered by this tool

The calculator ingests specific divisions of the San Diego Municipal Code and California state housing law. Each entry below cites the upstream source, when its values were last cross-checked, and which sections drive the math vs. which are referenced for context. The three levels are:

values encoded — numeric values from this section drive the calculator's output directly
rules modeled — the rule's logic runs in code, but no scalar value is read
referenced — cited in audit notes and disclaimers for context but not driving output

San Diego Municipal Code

SDMC Chapter 11, Article 3, Division 2 — Land Development Code Definitions and Calculations

Ingested Jan 8, 2026 · last verified Apr 22, 2026

Building height, floor area ratio (FAR), structured-parking exemptions, and dimensional measurement rules that every other zoning standard depends on.

§113.0234 · Floor area calculation; structured-parking exclusionvalues encodedDrives the parking-exempt-from-FAR rule used by every pathway.
§113.0246 · Lot frontage and street-side measurementrules modeled
§113.0270 · Building height — rooftop appurtenancesrules modeledExempted in most zones; CHLOZ overrides per the Coastal Height Limit Overlay flag.
§113.0273 · Story count vs. floor-to-floor inferencereferencedCode only specifies feet; story count is back-of-envelope (~10–11 ft floor-to-floor).

SDMC Chapter 13, Article 1, Division 3 — Use Regulations Tables

Ingested Jan 8, 2026 · last verified Mar 15, 2026

Table 131-03A residential / commercial / industrial use permissions per zone. Drives the residentialPermitted gate that excludes non-residential zones from yield estimation.

Table 131-03A · Use Regulations Table — residential permitted by zonevalues encoded

SDMC Chapter 13, Article 1, Division 4 — Residential Zones

Ingested Jan 8, 2026 · last verified Apr 22, 2026

RS / RM / RX / RT / RV zone development standards. Density caps, FAR, height, setbacks, lot dimensions, stepbacks, lot coverage, and the cardinal-direction setback regime for RM-4.

§131.0431 · RS zone standardsvalues encoded
§131.0441 · RM density and dimensional standardsvalues encoded9 RM zones currently in sd_zoning.json marked verified=false pending source cross-check.
§131.0443 · RM lot dimension and FAR by categoryvalues encoded
§131.0444 · Angled building envelope planerules modeledSurfaces as info flag when project height triggers the zone-group threshold.
§131.0445 · Graduated lot coverage (Table 131-04I)rules modeled
§131.0446 · Graduated FAR (RS-1-2 through RS-1-7; RM-5-12) and RM-4 cardinal setbacksvalues encodedCardinal-regime setback math pending parcel compass orientation — see LAUNCH_CHECKLIST.
§131.0450 · Setbacks (Table 131-04G/H)values encoded
§131.0453 · Stepback regime above 15 ft / 30 ftrules modeledImplemented in src/lib/calculations/layout/stepbacks.ts.
§131.0455 · RM private open spacereferenced
§131.0456 · RM common open spacerules modeledFires only on projects above 4 dwelling units.

SDMC Chapter 13, Article 1, Division 5 — Commercial Zones

Ingested Jan 12, 2026 · last verified Apr 22, 2026

CC / CN / CO / CR / CV / CP zone standards including the mixed-use residential requirement, residential FAR bonus, ground-floor commercial rules, façade articulation, parking orientation, and pedestrian-path requirements.

§131.0502–.0507 · Commercial zone purpose and density tablesvalues encoded
§131.0540 · Mixed-use residential requirement on commercial zonesrules modeledSurfaces as info flag; structural gating deferred per project memory.
§131.0541 · CO retail / office balance rulereferenced
§131.0543 · Setback regime; zero-setback option per (b); §131.0543(c) stepbacksrules modeled
§131.0546 · Commercial FAR and residential mixed-use FAR bonusvalues encoded
§131.0548 · Ground-floor minimum floor-to-floor heightvalues encoded
§131.0550 · Pedestrian-path requirements (lots ≥20,000 SF)referenced
§131.0552 · Transparency on commercial-zone street wallsreferenced
§131.0554 · Façade articulation (Table 131-05F)rules modeled
§131.0555 · No parking in required front / street-side yard (CO-1-1, CO-3-1/2/3)rules modeled
§131.0556 · Parking-lot orientation rule (>100,000 SF GFA on corner lots)referenced

SDMC Chapter 13, Article 2, Division 4 — Coastal Overlay Zones

Ingested Jan 15, 2026 · last verified Apr 22, 2026

Coastal Overlay Zone (COZ) designations and the Coastal Height Limit Overlay Zone (CHLOZ, Proposition D 30-ft cap). Determines when SDMC zoning amendments require California Coastal Commission certification before they apply.

§132.0403 · Coastal Height Limit Overlay Zone — 30 ft caprules modeledCoastal Commission certification flag fires on every analysis inside the COZ.

SDMC Chapter 13, Article 2, Division 5 — Historical Resources

Ingested Feb 4, 2026 · last verified Apr 22, 2026

Designated historic resources and historic district overlay; CEQA historical-resource review trigger; Historic Resources Board approval requirements for exterior modifications.

§132.0505 · Historic resource and district designation effectsrules modeledFlag-only today; SB-79 historic exclusion handled in src/lib/gis/sources.ts via the SB 79 City layer's historic field.

SDMC Chapter 14, Article 1, Division 3 — Accessory Dwelling Units (Local)

Ingested Jan 22, 2026 · last verified Mar 15, 2026

Local ADU regulations layered on top of state ADU statute, including the ADU Home Density Bonus pathway implementation.

§141.0302 · ADU Home Density Bonusvalues encodedPer-pathway calc in src/lib/calculations/pathways/aduHomeDensityBonus.ts.

SDMC Chapter 14, Article 3, Division 7 — Affordable Housing Implementation

Ingested Jan 22, 2026 · last verified Apr 22, 2026

Local implementation of state density-bonus law plus San Diego–specific affordable-housing programs: Complete Communities Housing Solutions (CCHS), Micro-Unit Density Bonus, Inclusionary Housing in-lieu fees, and the Realistic Development Capacity stacking method.

§143.0720 · Affordable Micro-Unit Density Bonusvalues encoded
§143.1010 · Inclusionary Housing in-lieu fees and CCHS interactionsrules modeledPer-SF in-lieu rate sourced from IB-532 — see corpus entry sdmc-ib-532.
§143.1015 · Complete Communities Housing Solutions (Tiers 1–4)values encoded
§142.13 · Inclusionary Affordable Housing Regulationsrules modeledTrigger condition (≥2 units), on-site vs. in-lieu election, and the obligation calculus. Rate ingested separately via IB-532 (see corpus entry sdmc-ib-532).
§142.1306 · Annual CCI adjustment of in-lieu raterules modeledIndexes the IB-532 rate annually; drives the July re-verification cadence.

City of San Diego Information Bulletin 532 — Affordable Housing Implementation Fee

Ingested May 1, 2026 · last verified May 1, 2026

Annual per-square-foot inclusionary in-lieu fee schedule. CCI-adjusted under SDMC §142.1306; new rate publishes effective July 1 each year. Drives the dollar-amount line on every market-rate pathway in the calculator's Phase A fee module.

IB-532 · Affordable housing implementation fee — per-SF ratevalues encoded$25.92/SF effective 2025-07-01. Stored in supabase inclusionary_in_lieu_rate (single-row table). Re-verify each July when the new IB-532 revision publishes.

City of San Diego Public Utilities Department — Sewer + Water Capacity Fees

Ingested May 1, 2026 · last verified May 1, 2026

Sewer capacity fee per Equivalent Dwelling Unit (EDU) and water capacity fee per building meter size. Both charged at building permit issuance. Annual cadence; rate ingestion via two Supabase tables (sewer_capacity_fees single-row, water_capacity_fees by meter size).

Sewer capacity fee · Per-EDU raterules modeledSchema: sewer_capacity_fees (single-row). v1 calc uses 1 EDU per MF unit; bedroom-count-aware EDU refinement deferred.
Water capacity fee · Per-meter-size rate (3/4", 1", 1-1/2", 2", 3", 4", 6")rules modeledSchema: water_capacity_fees keyed by meter_size string. v1 calc uses unit-count → meter-size heuristic; fixture-unit-count refinement requires unit-mix data not currently in calculator scope.

City of San Diego Development Impact Fees — FY 2026 Master Fee Schedule

Ingested May 1, 2026 · last verified May 1, 2026

Three-layer DIF architecture: (1) Build Better San Diego CITYWIDE DIFs by project type × unit-size bracket × five asset types (Park, Fire, Fire Underserved, Library, Mobility); (2) per-community overlays — FBA Communities (12 newer CPAs) and Community DIF Methodology (30+ established CPAs); (3) citywide constant overlays — RTCIP per DU plus Otay Mesa Local Mobility DIF. The stacking semantics between Layer 1 (citywide) and Layer 2 (community) — addsTo vs. replaces — are pending verification with the City. Until resolved, the calculator returns an 'integration pending' placeholder rather than risking 2x-off totals.

Build Better SD Citywide DIFs (FY 2026) · Park / Fire / Fire-Underserved / Library / Mobility — citywide rates by project type × unit-size bracketrules modeledSchema: dif_citywide_rates. Seeded empty pending stacking-question resolution (LAUNCH_CHECKLIST). Once seeded, calc sums all five asset types per unit.
Per-community DIF overlays · FBA Communities + Community DIF Methodology — per-CPA ratesrules modeledSchema: dif_community_overlays. Each row carries an 'applies' discriminator (addsTo | replaces | pending) capturing the stacking rule. v1 ingestion ships rows in 'pending' state until verified individually.
RTCIP + Otay Mesa Local Mobility · Citywide constant DIF overlaysrules modeledSchema: dif_citywide_overlays (single-row table). RTCIP $3,047.57/DU citywide; Otay Mesa Local $13,916/MF unit additional to citywide. Both pending Layer 1 seeding.

California state law

Cal. Gov. Code §65995 — School Impact Fees

Ingested May 1, 2026 · last verified May 1, 2026

Statutory cap on school impact fees per square foot of residential / commercial development. SAB (State Allocation Board) publishes Level I caps annually; districts elect Level I / II / III within the cap. Most San Diego parcels pay two districts (one elementary + one high-school) per Cal. Gov. Code §17620 et seq. The calculator's Phase A school-impact module is gated on (a) per-district rate ingestion and (b) school-district GIS overlay lookup — both pending.

§65995 · Statutory cap on per-SF school impact feesrules modeledSchema: school_impact_fees, keyed by (district_name, district_type). Schema in place; rate ingestion + GIS district overlay lookup pending. Once both ship, calc sums each applicable district's rate × MDU floor area.
§65995(b)(3) · Statutory base rate (Level I)referencedCurrently around $5/SF residential per SAB annual cap; verify against current SAB publication when ingesting district rates.
§17620 · School district authority to charge developer feesreferenced

Cal. Gov. Code §65915 — State Density Bonus Law (incl. AB 1287)

Ingested Jan 8, 2026 · last verified Apr 22, 2026

Statewide density-bonus entitlement for projects with affordable units. Drives the Affordable Density Bonus and Stacked Density Bonus pathways. AB 1287 amendments enable a second bonus on top of the first when commitments hit the maximum tier.

§65915(b) · 5-unit minimum thresholdrules modeled
§65915(d) · Concessions, incentives, and waiversreferencedFlagged in pathway audit notes when the project would require a §65915(d)/(e) height waiver.
§65915(f) · Density-bonus tables — VLI / LI / Mod commitment thresholdsvalues encodedTable loaded from supabase density_bonus_table.
§65915(p) · Bonus units exempt from FARrules modeled
§65915(q) · Bonus density rounds uprules modeled
AB 1287 (2023) · Stacked second bonus on Moderate Income or Very Low Incomevalues encodedImplemented in src/lib/calculations/ab1287.ts.

Cal. Gov. Code §§66313–66324 — State ADU Statute (incl. SB-1211)

Ingested Jan 22, 2026 · last verified Apr 22, 2026

Statewide ADU and JADU rules: ministerial approval, density-bonus interactions, lot-line setbacks, and the SB-1211 (2024) Multifamily ADU Expansion that adds detached + conversion ADUs on parcels with existing multifamily.

§66314(d)(1)(B)(ii) · Two state-mandated DETACHED ADUs on multifamily lotsvalues encodedThreaded through every multifamily pathway.
§66323 · SB-1211 Multifamily ADU Expansion (2024)values encodedPer-pathway calc in src/lib/calculations/pathways/sb1211.ts.

SB 79 — Transit-Oriented Development By-Right (eff. 2026-07-01)

Ingested May 1, 2026 · last verified May 1, 2026

State preemption of local zoning's density / FAR / height for parcels within ½ mile of qualifying Transit-Oriented Development stops. Pathway live; eligibility currently sourced from the City of San Diego's draft implementation map. Will swap to SANDAG's official map when published.

SB 79 (2025) · Tier 1 / Tier 2 stop classification + by-right standardsvalues encodedSourced from Hosted/SB79_Areas_Draft/FeatureServer/670 via src/lib/gis/sources.ts.

AB 2097 — Parking Elimination Near Transit (2022)

Ingested Jan 22, 2026 · last verified Mar 15, 2026

Eliminates parking minimums on residential, mixed-use, and commercial development within ½ mile of a major transit stop. Applied via the Transit Priority Area flag.

AB 2097 (2022) · Parking minimums eliminated near major transitrules modeled

Cal. Public Resources Code §2621 et seq. — Alquist-Priolo Earthquake Fault Zoning

Ingested Jan 12, 2026 · last verified Jan 12, 2026

Statutory 50-ft setback from active fault traces and required site-specific fault investigation before permits.

PRC §2621 · Alquist-Priolo zone definitions and requirementsreferencedSurfaced as global flag when GIS detects a parcel within or adjacent to the Alquist-Priolo zone.

Environmental and natural hazard

Flood zones — FEMA National Flood Hazard Layer (via City of San Diego)
Fire Hazard Severity Zones — CAL FIRE (via San Diego Fire-Rescue)
Earthquake Fault Zones — California Geological Survey, Alquist-Priolo program
Drinking water service areas — California State Water Resources Control Board

Affordability and income limits

State Income Limits and Maximum Allowable Rents — California Department of Housing and Community Development (HCD). Current vintage: 2025.

Transit and air navigation

Trolley lines and stops — SANDAG / Metropolitan Transit System
Airport Influence Areas, ALUCP Safety Zones, and FAA Part 77 surfaces — San Diego County Regional Airport Authority (via City of San Diego)

What the analysis engine actually models

The Regulations page documents the full body of San Diego and California housing law that shapes feasibility. The engine implements a subset of that as per-pathway unit-count math; the rest is either documented for context, factored in as an eligibility / overlay flag, or pending implementation. Honest breakdown:

Modeled as a per-pathway unit-count calculation

Base Zoning (with state-mandated ADUs)
State Density Bonus Law / Affordable Density Bonus (incl. AB 1287 second bonus)
Affordable Micro-Unit Density Bonus
Complete Communities Housing Solutions (Tiers 1–4)
ADU Home Density Bonus
Stacked Affordable + ADU HDB combination (City's Realistic Development Capacity method)
SB-1211 Multifamily ADU Expansion

Factored into eligibility and constraints (no separate yield card)

Transit Priority Area (TPA) and Sustainable Development Area (SDA) — gate density-bonus tiers and parking
Coastal Overlay Zone, Coastal Height Limit Overlay Zone — surface as flags; CHLOZ caps height
Airport Influence Area, ALUCP Safety Zone, FAA Part 77 — surface as flags; Safety Zone may render residential ineligible
FEMA Flood Zone, Fire Hazard Severity Zone, Alquist-Priolo Fault Zone — surface as flags; FHSZ “Very High” excluded from SB-79 once that program ships
Designated Historic Districts and Resources — surface as flags; excluded from SB-79 once that ships
Inclusionary Affordable Housing fees — looked up by zone for cost context
AB-2097 (parking elimination near transit) — applied through the parking calc when in TPA
Site conditions: corner lot, alley adjacency, overhead utility lines, storm drain easements, utility undergrounding districts, trolley-line frontage

Documented but not yet modeled in the analysis engine

SB-9 — California HOME Act (lot-split / duplex on RS lots)
SB-79 — Abundant Homes Near Transit (effective July 1, 2026; awaiting authoritative SANDAG / California HCD eligibility map)
AB-2011 — Affordable Housing and High Road Jobs Act (commercial-to-residential)
SB-4 — Affordable Housing on Faith Lands
SB-684 — Starter Home Revitalization Act
AB-2074 — Downtown Revitalization Act
Junior Accessory Dwelling Units (JADUs) — informational; RS-only, not in the multifamily pathway stack
Hillside Review / Steep Hillside Overlay, Mobilehome Park Overlay, Sensitive Coastal Overlay — flagged where detected, but no specific yield adjustment
Approval-pathway laws that don't directly affect unit counts: HAA, SB-330, SB-35 / SB-423, Builder's Remedy. These shape entitlement timing and risk; they don't change what numbers the engine returns.

AI Q&A assistant

Response generation — Anthropic Claude (claude-sonnet-4-6) via the Anthropic API
Knowledge base — manually-maintained representation of San Diego Municipal Code Chapter 13, Articles 1, Divisions 4 and 5 (sd_zoning.json), plus a per-request analysis-context block derived from the Supabase zone tables (zone-specific FAR, density, height, tier breakpoints, pathway results) when the assistant is consulted from a results page
Rate limiting — Upstash Redis (per-user request counts only; no question content)

See the Privacy Policy for what AI question/answer data is sent to Anthropic and what is logged on our infrastructure.

For details on exactly what information is sent to these services and how your data is handled during a query, see the Privacy Policy.