Key facts: Portsmouth
- Colonists settled the west bank of Portsmouth's harbor in 1630, and the Jackson House has stood since 1664.[1]
- The fire of 1813 burned 244 buildings, and later brick rules left a downtown of masonry that stays wet for a long time.[1]
- The city's listed 66-foot elevation means little at the waterline, where a coastal storm can combine high tide, wind and rain.
Slow is often right
Hand-hewn timber, wide boards and plaster can crack or warp under rapid drying. The fire of 1813 burned 244 buildings, and later brick rules left a downtown of masonry that stays wet for a long time.[1] Ask how the contractor monitors progress, and whether they have worked in old buildings.
A closer look in Portsmouth
The Piscataqua's edge
The Piscataqua is a swift tidal estuary and the Maine boundary.[2] The city's listed 66-foot elevation means little at the waterline, where a coastal storm can combine high tide, wind and rain. Check the flood maps if you are near the harbor or a tidal creek.
Flood claims recorded in Rockingham County
Portsmouth sits in Rockingham County. FEMA publishes every National Flood Insurance Program claim with personal details removed, which gives a plain record of where water has reached insured buildings here.
| Measure | Count |
|---|---|
| Flood insurance claims on record | 2,165 |
| Year with the most claims | 2006 (265) |
| Largest named event | Flooding (242) |
| Claims outside high-risk A and V zones | 23% |
| Claims on buildings built before 1975 | 66% |
County-wide counts of insured claims only. Uninsured losses, burst pipes and appliance leaks are not in this data.
What the Portsmouth claim record shows
For Portsmouth homes, the local precedents are the events behind the most Rockingham County claims: Flooding (242 claims), The "Halloween" Storm (239 claims) and March 2010 Nor'Easter (86 claims).
Around Portsmouth, about 77% of county claims with a recorded zone came from the high-risk A and V zones, so checking your address on the FEMA flood map tells you a lot here.
If your Portsmouth home is older, note that buildings from before 1975 make up 66% of county claims with a known build date. Many predate current flood maps, so inspect low outlets, ductwork and subfloors closely after any water event.
Federal disaster history for Rockingham County
FEMA lists 35 federal declarations covering Rockingham County. The most common types are severe storm (12), snowstorm (6) and flood (5). The latest are Severe Winter Storm and Flooding in 2024, Severe Storms and Flooding in 1998 and Covid-19 Pandemic in 2020. When a declaration is open, federal aid may be available to Portsmouth residents, so ask about it alongside your insurance claim.
Portsmouth weather and your home
Weather records for Portsmouth from 2015 through 2024 average 46 inches of precipitation a year, and December and October are the wettest months. The area averages 10.1 days a year with an inch or more.
Portsmouth falls to 20°F or below on about 42 nights a year, which puts pipes in exterior walls, crawl spaces and garages at risk.
When rain falls in Portsmouth
Seasonal averages for Portsmouth, 2015 through 2024. Plan roof, gutter and sump pump checks before the wettest stretch.
| Season | Average | Share of year |
|---|---|---|
| January to March | 11.4 in | 25% |
| April to June | 10.8 in | 23% |
| July to September | 11.1 in | 24% |
| October to December | 13.0 in | 28% |
Modeled from Open-Meteo historical weather data. Precipitation includes rain and melted snow.
Portsmouth home checklist from these records
- Don't rely on recent quiet years. Only 22% of Rockingham County claims date from 2015 or later, so older floods still show what can happen.
- Insulate exposed pipes before 42-plus hard-freeze nights arrive, and know your main shutoff.
- Test any sump pump before December, since Portsmouth averages 10 days a year with an inch or more.
- Keep dated photos of each room. After Flooding, 242 insured Rockingham County owners filed claims at about the same time.
What to tell the Portsmouth contractor
- The age of the home
- Whether original finishes are wet
- Whether tidal water reached you
Services Portsmouth callers ask about
Questions
Portsmouth water damage questions
Can a historic Portsmouth home be saved after a leak?
Usually, with care. Move slowly, document everything, and test for lead before disturbing finishes.
How wet is Portsmouth?
About 50.65 inches of precipitation and 65 inches of snow a year on average.[1]