ZIP 20850 · Maryland
Neighborhood data for ZIP 20850 — Rockville, Maryland
Federated public-records summary for ZIP 20850. Twelve dimensions below — water, flood, wildfire, crime, schools, radon, air, lead, tax, deeds, zoning, sex-offender registry — each sourced from its primary federal or county regulator and refreshed on that regulator's cadence. Every claim cites its source; see methodology for refresh cadence and limitations.
Last verified 2026-06-03 · methodology
Water quality
Source: EPA SDWIS
Drinking-water violations, lead-copper results, and health alerts per community water system, sourced from EPA SDWIS and refreshed quarterly.
Water quality for Rockville →
Flood zone
Source: FEMA NFHL
Official FIRM flood-zone classifications by address with base flood elevations, sourced from the FEMA National Flood Hazard Layer and refreshed quarterly.
Flood zone for Rockville →
Wildfire risk
Source: USDA Forest Service
Community-level wildfire hazard potential on a five-step scale, sourced from USDA Forest Service Wildfire Risk to Communities and refreshed annually.
Wildfire risk for Rockville →
Air quality
Source: EPA AirNow
Current AQI and multi-year averages from the nearest EPA AirNow monitoring station, per US ZIP code.
Air quality for Rockville →
Crime
Source: FBI UCR
Reported crime per 100,000 residents, normalized across years and agencies, sourced from the FBI Crime Data Explorer.
Crime for Rockville →
Schools
Source: NCES Common Core of Data
District boundary, enrollment, student-teacher ratio, and school demographics sourced from the NCES Common Core of Data.
Schools for Rockville →
Radon
Source: EPA Radon Zones
County-level radon risk zone (1, 2, or 3) sourced from the EPA Map of Radon Zones, with state-level supplementary testing context.
Radon for Rockville →
Lead pipes
Source: EPA LCRR + RTI National Lead Pipe Map
Lead service-line counts reported under the 2024 Lead and Copper Rule Revisions, sourced from EPA LCRR and RTI's national map.
Lead pipes for Rockville →
Property tax
Source: County assessors
Millage rates and assessment methodology from county assessor offices, covering the top 50 US metros.
Property tax for Rockville →
Deed activity
Source: County recorders
Recent deed-transfer counts aggregated to ZIP level, sourced from county recorder offices. Homeowner names are never cached or republished.
Deed activity for Rockville →
Zoning
Source: Municipal planning departments
Residential, commercial, industrial, and mixed-use zoning classifications sourced from municipal planning departments.
Zoning for Rockville →
Sex offender registry
Source: NSOPW (federal deep-link)
Deep-link to the Department of Justice's National Sex Offender Public Website (NSOPW). zipradar does NOT cache or republish registry records.
Sex offender registry for Rockville →
Montgomery County (MD), MD
ZIP 20850 is in Montgomery County (MD). County-level data anchors property tax (assessor), deeds (recorder), and the EPA Map of Radon Zones.
Montgomery County (MD) dashboard →Why ZIP 20850?
Rockville, Maryland is one of the first six zip codes zipradar covers while the federation layer rolls out. Coverage expands to the top 500 zips by Week 2, full 41,000+ US zip codes by Month 2. Want your zip added sooner? Email us.
Frequently asked questions
What ZIP code is Rockville, MD?
Rockville, Maryland is in ZIP 20850 (Montgomery County (MD)). zipradar federates neighborhood data for this ZIP across 12 dimensions: water, flood, wildfire, crime, schools, radon, air, lead, property tax, deeds, zoning, and sex-offender registry — each sourced from the primary federal or county regulator.
What county is ZIP 20850 in?
ZIP 20850 (Rockville, MD) is located in Montgomery County (MD), Maryland. The county-level data anchors property tax records (assessor), deeds (recorder), and EPA Map of Radon Zones for this ZIP.
Where does zipradar get data for ZIP 20850?
Federated from primary sources: EPA (water, radon, air), FEMA (flood), FBI (crime), NCES (schools), USFS (wildfire), and Montgomery County (MD) county records (property tax, deeds, zoning). Every claim cites its source and is refreshed on the regulator's cadence — see /methodology for limitations.
Is ZIP 20850 data current?
Last verified 2026-06-03. Refresh cadence varies by source: EPA SDWIS quarterly, FEMA NFHL on map updates, FBI Crime Data Explorer annually, NCES annually, county assessor records typically annually. See /methodology for per-source cadence and known lag windows.