Flood zone · ZIP 03801
Flood zone in Portsmouth (NH), NH
ZIP 03801 (New Hampshire) — flood zone summary sourced from FEMA NFHL. Data lands this week as the FEMA NFHL ingestion pipeline rolls out.
Last verified 2026-04-26 · methodology
What lands here
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.
Source & refresh
FEMA NFHL. Refreshed quarterly loma updates. Stale data is flagged, never silently served. Primary source →
Limitations specific to this source
For an official flood-zone determination (required by lenders), consult the FEMA Map Service Center directly. zipradar shows informational classifications only.
New Hampshire context
Radon, lead in older housing
New Hampshire is uniformly Zone 1 radon. Older Manchester + Nashua + Portsmouth housing stock carries lead-service-line risk. Coastal flood zones limited to small NH coastline.
See New Hampshire state page for the full state-level rollup across all 12 dimensions.
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Editorial deep-dives explaining the source data, its limits, and how to read it.
Flood zones explained — what AE, X, and VE actually mean
Plain-English guide to FEMA flood-zone codes (A, AE, AH, V, VE, X, X-shaded). What the 1% and 0.2% annual-chance zones mean for your property and your insurance.
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FEMA flood zones — AE vs. X vs. VE in plain English
FEMA's National Flood Hazard Layer maps every US property's flood-zone designation. Here's what AE, X, VE, and AO actually mean for your insurance bill.
Full dashboard for ZIP 03801
Flood zone is one of twelve dimensions zipradar federates per address. See the full federated summary for ZIP 03801:
Open Portsmouth (NH), NH dashboard →