zipradar

ZIP 20850 · Maryland

Neighborhood data for ZIP 20850 — Rockville, Maryland

This page indexes the twelve public-records dimensions zipradar covers for ZIP 20850 — water, flood, wildfire, crime, schools, radon, air, lead, tax, deeds, zoning and the sex-offender registry — and names the federal or county regulator behind each. Follow a dimension for what that source covers, what it leaves out, and how often the regulator publishes; see methodology for the full cadence and limitations.

Last verified 2026-09-15 · 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 Air Quality System (AQS), annual county summary

    2025 annual air-quality summary (median AQI, category, unhealthy-day counts) by county, from EPA's Air Quality System, 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 370 zip codes zipradar covers today, and coverage keeps expanding toward the full 41,000+ US zip code set. 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?

zipradar names the primary source for each dimension: EPA (water, radon, air), FEMA (flood), FBI (crime), NCES (schools), USFS (wildfire), and Montgomery County (MD) county records (property tax, deeds, zoning). Each dimension page links to that regulator's own data — see /methodology for what's covered per source and how current it is.

Is ZIP 20850 data current?

Last verified 2026-09-15. 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.

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