California Geology & Faults

Well status from the CalGEM (formerly DOGGR) database.
216,581 wells statewide · complete at zoom 12+
Below zoom 12 the densest fields are thinned to fit tile limits.

Sites scored against the 100-point system in Multifamily_Criteria.docx: redevelopment potential (30), site suitability (25), zoning and housing capacity (25), location and rental market appeal (10), development constraints (5).
185,082 parcels in Los Angeles and Orange counties were scored after gating on lot area of 8,000 sq ft or more and a general plan designation that permits housing or plausibly converts to it.
Scored out of 90, not 100. Height limits, setbacks and parking minimums are numeric standards held in each of the 89 jurisdictions' zoning ordinance text; no layer here expresses them, so those five points are left unscored rather than guessed. Street frontage is folded into lot width, which needs no street right-of-way layer to measure.
Open the panel from the menu for the ranked table.

DTSC residential sampling around the former Exide Technologies battery smelter in Vernon. One point per property, carrying the representative concentration DTSC computed from that property's samples — a 95% upper confidence limit for most, the maximum for the rest.
80 ppm is California's residential screening level for soil lead. 96.6% of these properties are above it.
414,883 analyses at 10,331 properties, 2014–2025.

California Geological Survey Borehole Database.
12,478 of them carry logged lithology.

State-regulated zones around active fault traces.
1,463 zones · CGS · released 1974–2025

California DSOD approved dam-failure inundation maps, as of 1 April 2026. 1,160 modelled scenarios across 781 dams, statewide — a breach path runs far downstream, so this one is not clipped to the two counties.
Generalised to about 110 m. The source carries 79 million vertices, most of it raster speckle; parts under 5 ha and islands under 10 ha are dropped. Good for which areas lie downstream of a dam, not for whether a given parcel is inside the line.
Areas overlap where several dams drain the same valley, which is why the fill is faint. Click for the dam, the scenario and its hazard class.

FEMA National Flood Hazard Layer, California, 8 October 2026. Los Angeles and Orange counties — the same footprint as the parcels.
Outlines are simplified to about 5 m. A zone boundary is modelled, not surveyed, and FEMA publishes its panels at 1:12,000, where 5 m is under half a millimetre on the page.
Areas mapped as minimal hazard are drawn as a hairline from zoom 12 rather than filled: they cover most of both counties, and leaving them out entirely would make “mapped and minimal” look the same as “never mapped”.
Click a zone for its designation, base flood elevation and depth.

SCAG 2016 land use, parcel by parcel — 2,770,865 parcels across Los Angeles and Orange.
Keyed on the same APN as the parcel layer, so a click gives the land use for that parcel rather than for a neighbourhood.
The two counties encode it differently — LA stores a bare code, Orange the code and its label — so the descriptions come from Orange and cover 118 of the 129 codes LA uses.
2016 vintage: older than the parcels beneath it.

CAL FIRE Fire Hazard Severity Zones, 2025 Phase 4.
Local Responsibility Area only — the state-responsibility and federal lands are a separate dataset and are blank here, which is not the same as unhazardous.
NonWildland is the absence of a rating rather than a low one, so it is drawn unfilled but still answers a click.

CGS tsunami hazard areas for emergency planning, one polygon per coastal county.
These are evacuation-planning extents, drawn deliberately generously: they are not a prediction of any single wave.
The source ships each county twice, as the hazard area and its inverse; only the hazard halves are here.

Federally designated critical habitat — 150 units covering 144 species in California, from the USFWS national release.
Coloured by the species' listing status. The designation is a separate thing: 12 units are still Proposed for species already listed.
Units overlap where several species share ground, so a click reports one of them, not all.
Unit names are not in this release — every California record carries a placeholder telling you to fetch the per-species shapefile — so they are omitted rather than shown blank.

Areas required to be investigated for earthquake-induced landslide before development.
41,752 zones · CGS Seismic Hazard Zones · 131 quadrangles, released 1997–2025
Mapped quadrangles only — blank ground is unmapped, not unhazardous.
Click a zone for its quadrangle map and report.

Areas required to be investigated for liquefaction before development.
2,031 zones · CGS Seismic Hazard Zones · released 1997–2006
Click a zone for its quadrangle map and report.

2001 data — 25 years old. Alignments are approximate and the network has changed since.
National Pipeline Mapping System, clipped to California · 27,864 segments · 93 operators
Never use this to locate a pipeline on the ground. Call 811 before you dig.

2025 median household net worth · US Census blocks
Vector tileset · 235,799 blocks · 72 attributes

USGS elevation contours from The National Map, derived from the 3DEP elevation model — the published topographic contours, not something interpolated here.
The interval follows the zoom, as it does on a paper quad: 100 ft at around 1:600,000, 50 ft from 1:150,000, and the full large-scale set with supplemental and depression contours below 1:50,000. Labels are drawn by the service.
Rendered on request rather than from a tile cache, so the first view of an area takes a moment.

Contoured from 44,745 DWR monitoring wells, each carrying its most recent depth-to-water reading. Feet below ground surface, so a larger number is a deeper water table; negative values are artesian, where the potentiometric surface stands above ground.
Interpolated no further than 3 km from a well, which is the 99th percentile of the spacing between them, so no water table is drawn across ground nobody measured.