Groundcheck Report inputs

Data layers

Groundcheck uses these public datasets to generate the current Groundcheck Report.

National

National data layers

floodplain

FEMA floodplain analysis

Checks whether the saved parcel geometry (or, if no parcel boundary is available, the address point) intersects FEMA National Flood Hazard Layer flood zones.

Source: FEMA National Flood Hazard Layer
Method: Parcel polygon intersection, or a buffered point query when no parcel boundary is available

floodplain

National Levee Database screening

Checks whether the saved parcel geometry, or an approximate 30-meter point fallback, intersects a public National Levee Database leveed-area polygon.

Source: U.S. Army Corps of Engineers National Levee Database
Method: Parcel polygon intersection against NLD leveed areas, or a clearly labeled 30-meter point fallback

wetlands

National Wetlands Inventory analysis

Checks whether the saved parcel geometry (or, if no parcel boundary is available, the address point) intersects mapped wetlands or water features from the National Wetlands Inventory.

Source: USFWS National Wetlands Inventory
Method: Parcel polygon intersection, or a buffered point query when no parcel boundary is available

habitat

USFWS designated critical habitat screening

Checks final and proposed USFWS critical-habitat polygons against the saved parcel, with an approximate buffered-point fallback when no parcel boundary is available.

Source: U.S. Fish and Wildlife Service Critical Habitat
Method: Parcel polygon intersection against separate final and proposed critical-habitat layers, or a 30-meter buffered point query

public_lands

Public land ownership screening

Checks whether the parcel intersects federal, state, regional, local, or territorial fee-owned public land in PAD-US, while excluding tribal, private, nonprofit, easement, and proclamation-only records.

Source: USGS Protected Areas Database of the United States (PAD-US) 4.1
Method: Parcel polygon intersection with estimated overlap, or a clearly labeled 30-meter buffered point query when no parcel boundary is available

historic

Historic and cultural resource screening

Checks whether the saved parcel geometry intersects public National Register of Historic Places points or polygons. Uses a small address-point buffer when no parcel boundary is available.

Source: National Register of Historic Places
Method: Parcel intersection against public National Register point and polygon layers

environmental

EPA regulated water facilities nearby

Counts nearby Clean Water Act regulated facilities and recent violation/enforcement indicators from EPA ECHO.

Source: EPA ECHO Facility Search - Wastewater/Stormwater/Biosolids
Method: One-mile radius search from the lookup point

environmental

EPA cleanup sites nearby

Screens for EPA-reported Superfund, RCRA corrective-action, Brownfields, federal cleanup, and emergency-response locations near the property.

Source: U.S. EPA Cleanups in My Community (CIMC)
Method: One-mile point-radius query from the saved property lookup coordinate

soils

SSURGO soils screening

Checks USDA NRCS SSURGO soils for drainage, runoff, slope, septic drainfield and dwelling limitations, water table depth, and bedrock depth. Includes survey version dates and falls back to an approximate address point lookup when no parcel boundary is available.

Source: USDA NRCS Soil Data Access / SSURGO
Method: Parcel polygon intersection with SSURGO map units, component engineering interpretations, and map-unit depth estimates, or an approximate point lookup when no parcel boundary is available

slope

USGS 3DEP slope screening

Samples USGS 3DEP elevation across the parcel boundary and centroid to estimate the steepest and average grade.

Source: USGS 3D Elevation Program (3DEP)
Method: Elevation sampling at parcel vertices plus centroid with pairwise slope estimation

roads

Road adjacency and traffic exposure

Checks Census TIGERweb road centerlines within 75 meters, distinguishes a 30-meter apparent-adjacency screen from broader proximity, and flags traffic or access questions without claiming legal frontage.

Source: U.S. Census Bureau TIGER/Line Roads
Method: Parcel-to-road centerline distance screening across primary, secondary, and local TIGERweb layers, or an approximate 75-meter point screen when no parcel boundary is available

roads

Rail line proximity screening

Screens the parcel and a 300-meter surrounding area for mapped current and former FRA rail centerlines, with approximate centerline distance and network-status context.

Source: Federal Railroad Administration North American Rail Network Lines
Method: Parcel-to-rail centerline distance screening against U.S. FRA NARN segments, or an approximate 300-meter point screen when no parcel boundary is available

Maryland

Maryland data layers

wetlands

Maryland Wetlands of Special State Concern screening

Checks whether the saved parcel intersects a mapped Maryland Wetland of Special State Concern or falls within its 100-foot development buffer.

Source: Maryland iMAP Wetlands of Special State Concern
Method: Parcel intersection and 100-foot proximity query, or a clearly labeled 100-foot point fallback

protected_lands

Maryland protected lands and conservation easements

Checks Maryland iMAP for DNR-owned properties, DNR conservation easements, and land protected by private conservation groups through ownership or easement.

Source: Maryland iMAP Protected Lands
Method: Parcel polygon intersection with estimated overlap, or a clearly labeled 30-meter buffered point query when no parcel boundary is available

maryland

Maryland Critical Area screening

Checks whether the saved parcel geometry intersects Chesapeake Bay Critical Area designations from Maryland iMAP.

Source: Maryland iMAP Critical Areas
Method: Parcel polygon intersection against town and county Critical Area layers

zoning

Maryland zoning context

Shows the parcel record's local zoning code with a plain-language statewide generalized category and the local authority that controls the official zoning map and ordinance.

Source: Maryland iMAP Parcel Boundaries and Maryland Department of Planning Generalized Zoning
Method: Maryland parcel assessment lookup plus statewide generalized-zoning point lookup

development

Developed vs. vacant land screening

Uses Maryland SDAT year-built, structure square footage, and improvement value fields to flag whether the parcel already has an existing structure.

Source: Maryland SDAT Real Property Assessment Data
Method: Maryland parcel assessment field lookup

utilities

Public water and sewer availability

Uses Maryland SDAT public water, public sewer, and street paved fields to flag utility availability and well/septic risk.

Source: Maryland SDAT Real Property Assessment Data
Method: Maryland parcel assessment field lookup

Atlantic, Gulf, Great Lakes, Puerto Rico, and U.S. Virgin Islands coasts

Atlantic, Gulf, Great Lakes, Puerto Rico, and U.S. Virgin Islands coasts data layers

coastal

Coastal Barrier Resources System screening

Checks whether the property intersects a CBRS System Unit, Otherwise Protected Area, or the mapped 20-foot boundary-accuracy zone that may affect federal assistance and flood-insurance eligibility.

Source: U.S. Fish and Wildlife Service Coastal Barrier Resources System
Method: Parcel polygon intersection against CBRS prohibition and accuracy-zone layers, or a clearly labeled 30-meter point fallback

Louisiana Coastal Zone

Louisiana Coastal Zone data layers

coastal

Louisiana Coastal Zone permitting screening

Checks whether the saved parcel intersects Louisiana's legally designated Coastal Zone, where development that affects coastal waters can require Coastal Use Permit or related coastal-management review.

Source: Louisiana Department of Conservation and Energy Coastal Zone
Method: Parcel polygon intersection against the Louisiana Coastal Zone boundary, with an exact property-point fallback when no parcel boundary is available

27 states in the USGS 2022 compilation

27 states in the USGS 2022 compilation data layers

environmental

Documented orphaned oil and gas wells nearby

Screens for documented unplugged orphaned oil and gas wells within one mile of the property point in the USGS 2022 compilation.

Source: USGS Documented Unplugged Orphaned Oil and Gas Wells
Method: One-mile point-radius query against the 27-state USGS documented orphaned-well compilation

Virginia Chesapeake Bay Preservation Act localities

Virginia Chesapeake Bay Preservation Act localities data layers

environmental

Virginia Chesapeake Bay Preservation Area screening

Checks Virginia DEQ's mapped Resource Protection, Resource Management, and Intensely Developed Areas for Chesapeake Bay Preservation Act development-review context.

Source: Virginia DEQ Chesapeake Bay Preservation Act Areas
Method: Parcel polygon intersection, or an exact point fallback when no parcel boundary is available

Contiguous U.S.

Contiguous U.S. data layers

noise

Modeled transportation noise screening

Queries the live CDC OneMap service for the 2014 modeled road and aviation noise level at the property coordinate.

Source: USDOT Bureau of Transportation Statistics National Transportation Noise Map (CDC OneMap service)
Method: Point sample from the state's raster through the ArcGIS MapServer identify operation

United States and Puerto Rico

United States and Puerto Rico data layers

development

HUD LIHTC development-area screening

Checks whether the saved property point falls within HUD's public Qualified Census Tract or Difficult Development Area polygons for LIHTC development-finance context.

Source: HUD Qualified Census Tracts and Difficult Development Areas
Method: Exact property-point intersection against HUD QCT and DDA polygons, with source-vintage caveats preserved because the generic GIS layers do not expose a designation year