{"@context":"https://schema.org","@type":"Dataset","@id":"https://zipradar.org/topic/flood-zone/02451/","name":"Flood zone for ZIP 02451 — Waltham, MA","description":"Flood zone data for ZIP 02451 (Waltham, Massachusetts), sourced from FEMA NFHL.","topic":{"slug":"flood-zone","label":"Flood zone","source":"FEMA NFHL","sourceUrl":"https://www.fema.gov/flood-maps/national-flood-hazard-layer","refreshCadence":"Quarterly LOMA updates","summary":"Pages show the flood zone code, what it means in plain English (1% annual chance zone, 0.2% annual chance zone, or outside mapped hazard), and the base flood elevation where assigned.","limitations":"For an official flood-zone determination (required by lenders), consult the FEMA Map Service Center directly. zipradar shows informational classifications only."},"place":{"zip":"02451","city":"Waltham","state":"MA","stateFull":"Massachusetts","county":"Middlesex County","countySlug":"middlesex-county","geo":{"latitude":42.3765,"longitude":-71.2356}},"stateContext":{"topConcern":"Lead pipes, coastal flood, older housing","narrative":"Massachusetts has dense lead-service-line obligations under LCRR in Boston, Lowell, Worcester, Springfield. Coastal AE/VE zones along the South Shore + Cape. Older housing stock means lead-paint risk overlaps with LSL risk."},"radonZone":null,"airQuality":null,"datePublished":"2026-04-24","dateModified":"2026-09-07","canonicalUrl":"https://zipradar.org/topic/flood-zone/02451/","zipDashboardUrl":"https://zipradar.org/zip/02451/","zipDashboardApiUrl":"https://zipradar.org/api/zip/02451/","primarySourceUrl":"https://www.fema.gov/flood-maps/national-flood-hazard-layer","license":{"content":"CC-BY-4.0","attribution":"zipradar.org — https://zipradar.org/topic/flood-zone/02451/"}}