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B−Hazard risk Grade
Flood & hazards in Northampton · Environment Agency

Surface water, more than the river, is Northampton’s flood risk: 4% of homes, against 0.3% from rivers or the sea

On the Environment Agency’s maps, which allow for flood defences, “high or medium” means at least a 1 in 100 chance of flooding from rivers or the sea in any year. For hazard risk, Northampton grades B−: #26 of 31 in Northamptonshire.

1998worst recorded flood32flood warnings since 200699%in a radon Affected Area
In brief

What stands out about Northampton’s hazards

From the Environment Agency’s maps and records and the BGS radon atlas, below.

Rain, more than the river4% of homes sit where heavy rain can flood the streets, against 0.3% at risk from rivers and the sea.Remembers 1998Floodwater covered 240 hectares of today’s Northampton in 1998; 3,218 of today’s households live inside past flood outlines.The River Nene ran its 2nd-highest in November 20242.42 m at St Andrews Bypass on 25 November 2024, 36 cm under the record set in 1998.32 flood warnings since 2006For the parts of Northampton the Environment Agency warns directly; the most recent on 25 November 2024.
By hazard

What Northampton faces

Each hazard against its own yardstick; meters run from low to high on that yardstick.

Rivers and the sea

0.3%of homes at high or medium risk
More than the typical UK town · more than 54% of towns
525 homes by the EA’s own count

Surface water

4%of homes at high or medium risk
More than 56% of UK towns
Rivers and sea: 0.3%

Past floods

3years with a recorded flood
Last recorded: January 2004
3,218 households inside past outlines

The River Nene

1.03 mhighest in winter 2025–26 at St Andrews Bypass
20th-highest of 34 winters
Record 2.78 m, April 1998

Flood warnings

32flood warnings since 2006
63 flood alerts for the wider area
Last warning 25 November 2024

Radon

99%of the city in a radon Affected Area
Highest band here: Over 30% of homes
90% in squares of 5% or more
Not on this page: coastal erosion, subsidence and shrink-swell ground (the British Geological Survey licenses it), groundwater flooding and reservoir failure.
Hazard risk Grade

Northampton grades B− for hazard risk

Flood risk from rivers and the sea, against all UK towns.

Homes at high or medium flood risk (0.3%)Fewer than 46% of UK towns

The share of homes at high or medium risk from rivers and the sea, ranked against every UK town of 1,000 or more: fewer homes at risk is better. Towns with none at high or medium risk are ordered by their share at low risk, so they don’t all share one score. Surface water and radon aren’t graded: they are described below.

Flood map

Where the water goes in Northampton

Turn layers on and off. Blue is the risk from rivers and the sea; pink is where heavy rain collects. Both allow for flood defences.

Recorded flood: 1947Recorded flood: 1998Recorded flood: 2004© OpenStreetMap contributors · EA NaFRA2
HighMediumLowrivers & seaHighMediumLowsurface waterNorthampton’s built-up area

The river and sea risk follows the River Nene, the Dallington Brook and the Brampton Branch. Surface-water risk is spread across the city, in dips, underpasses and along small streams, which is why more homes are exposed to it.

Rivers and the sea

0.3% of Northampton’s homes are at high or medium risk from rivers or the sea

The Environment Agency’s national map, allowing for defences. A further 2% are at low risk.

High risk0.3%of homes · 1 in 30 a year or more456 homes, EA count
Medium riskunder 0.1%of homes · 1 in 30 to 1 in 10069 homes, EA count
Low risk2%of homes · 1 in 100 to 1 in 1,0002,270 homes, EA count
Where Northampton sits among 3,735 UK towns
35%None
23%Under 0.5%Northampton
9%0.5–1%
11%1–2%
11%2–5%
5%5–10%
3%10–20%
2%20% +

Share of each UK town’s homes at high or medium risk from rivers and the sea. 35% of UK towns have none; Northampton has more than 54% of towns.

Towns its size: 15th of 50 from the fewest homes at risk
#TownPeopleHigh or med.
1Southwark London307,0760%
2Islington London216,3090%
3Camden London209,3420%
…
13Hounslow London286,5910.3%
14Norwich Norfolk200,7440.3%
15Northampton Northamptonshire243,5270.3%
16Southend-on-Sea Essex182,2950.4%
17Swansea West Glamorgan170,0900.4%
…
49Oxford Oxfordshire170,7994.7%
50Kingston upon Hull East Riding of Yorkshire270,8166.3%

UK towns of 170,000 to 341,000 people.

The Environment Agency’s Risk of Flooding from Rivers and Sea (NaFRA2, June 2026) counts each postcode’s homes by band; the shares weight those postcodes by Census 2021 households. The EA counts include homes built since 2021.

Surface water

Heavy rain puts about 11.6 times as many Northampton homes at risk as rivers and the sea do

Surface water is rain that falls faster than drains and the ground can take it. It is mapped separately from rivers and the sea, and it is not in the Hazard risk Grade.

Surface water4%
Rivers and the sea0.3%
0%7%14% of homes

About 1.9% of homes are at high risk of surface-water flooding (a 1 in 30 chance or more each year) and 2.1% at medium risk: roughly 3,860 households. A further 5.1% face a low risk from surface water. That is more than 56% of UK towns.

~3,860
households at high or medium risk
5.1%
of homes at low risk
56%
of UK towns have a smaller share
122,127
addresses read on the map

Our estimate: every address in the city (ONS NSUL) read on the Environment Agency’s Risk of Flooding from Surface Water map (NaFRA2, 2025), each postcode’s share weighted by its Census 2021 households. Neither agency publishes a count of homes for surface water, so treat it as a guide; one street can differ from the next.

Flood history

Northampton has flooded in 3 recorded years since 1947, most of all in 1998

Every flood the Environment Agency has mapped inside Northampton’s built-up area, newest first. The record is fullest for big river floods; small and surface-water floods are often missing.

  1. 2004January 2004: River flooding recordedUnder 1 hectare inside today’s built-up area
  2. 1998April 1998: River flooding recorded240 hectares inside today’s built-up area
  3. 1947March 1947: River flooding recorded165 hectares inside today’s built-up area
The worst: 1998240 ha

Floodwater covered 240 hectares of what is now Northampton in 1998, the largest flood the record holds here (April).

3,218 of Northampton’s households today live inside the outline of a recorded flood.

Since 1998, the largest recorded flood inside the city covered under 1 hectare.

River levels

The River Nene in November 2024 rose to its 2nd-highest level since 1990

The highest level each winter (October to September) at the Environment Agency’s St Andrews Bypass gauge, since 1990. The river normally runs between 0.00 m and 1.24 m here.

Highest level each winter, metres
Winter 1990–91: highest 1.58 m · 9 days above the normal rangeWinter 1991–92: highest 2.42 m on 23 September 1992 · 32 days above the normal rangeWinter 1992–93: highest 2.16 m on 14 January 1993 · 63 days above the normal rangeWinter 1993–94: highest 2.11 m on 5 January 1994 · 86 days above the normal rangeWinter 1994–95: highest 1.91 m · 87 days above the normal rangeWinter 1995–96: highest 1.81 m · 24 days above the normal rangeWinter 1996–97: highest 1.43 m · 7 days above the normal rangeWinter 1997–98: highest 2.78 m on 10 April 1998 · 40 days above the normal rangeWinter 1998–99: highest 1.12 m · 0 days above the normal rangeWinter 1999–00: highest 0.98 m · 0 days above the normal rangeWinter 2000–01: highest 1.28 m · 1 days above the normal rangeWinter 2001–02: highest 0.74 m · 0 days above the normal rangeWinter 2002–03: highest 1.22 m · 0 days above the normal rangeWinter 2003–04: highest 0.72 m · 0 days above the normal rangeWinter 2004–05: highest 0.53 m · 0 days above the normal rangeWinter 2005–06: highest 0.49 m · 0 days above the normal rangeWinter 2006–07: highest 1.20 m · 0 days above the normal rangeWinter 2007–08: highest 1.10 m · 0 days above the normal rangeWinter 2008–09: highest 0.87 m · 0 days above the normal rangeWinter 2009–10: highest 0.68 m · 0 days above the normal rangeWinter 2010–11: highest 0.63 m · 0 days above the normal rangeWinter 2011–12: highest 0.97 m · 0 days above the normal rangeWinter 2012–13: highest 1.38 m · 2 days above the normal rangeWinter 2013–14: highest 1.19 m · 0 days above the normal rangeWinter 2016–17: highest 0.55 m · 0 days above the normal rangeWinter 2017–18: highest 0.99 m · 0 days above the normal rangeWinter 2018–19: highest 0.46 m · 0 days above the normal rangeWinter 2019–20: highest 1.06 m · 0 days above the normal rangeWinter 2020–21: highest 1.51 m · 2 days above the normal rangeWinter 2021–22: highest 0.88 m · 0 days above the normal rangeWinter 2022–23: highest 0.73 m · 0 days above the normal rangeWinter 2023–24: highest 1.38 m · 3 days above the normal rangeWinter 2024–25: highest 2.42 m on 25 November 2024 · 2 days above the normal rangeWinter 2025–26: highest 1.03 m · 0 days above the normal range’97–98’24–25’91–92Record 2.78 m, 1998Top of normal range
1990–912025–26
The highest days on record
  • 10 April 19982.78 m
  • 25 November 20242.42 m
  • 23 September 19922.42 m
  • 10 January 19922.16 m
  • 14 January 19932.16 m
  • 5 January 19942.11 m

The River Nene has topped its normal range on 358 days since 1990, most in the winters of 1994–95 and 1993–94. By its highest day, the winter of 2025–26 was the 20th-highest of the 34.

Environment Agency Hydrology API, St Andrews Bypass (station E2928), daily maximum level; the record and normal range from the EA’s stage scale. Live river levels are on GOV.UK’s Check for flooding.

Flood warnings

No flood warning or alert is in force for Northampton · 32 warnings in 20 years

The Environment Agency has 6 flood warning areas and 2 alert areas reaching into the city; warnings since the service began in 2006.

Now: no flood warnings or alerts for Northampton (checked 9 November 2026, 11:04). Check for flooding on GOV.UK →
Warnings and alerts each year for areas in Northampton
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Flood warning (flooding expected)Flood alert (flooding possible)

Of the 32 warnings, 13 were for River Nene at Billing Aquadrome and nearby business parks and 8 for Areas near the Wootton Brook in the Collingtree, Merefield and Shelfleys parts of Northampton. 2024 had the most warnings (16).

The most recent warning was on 25 November 2024.

Show the 8 warning and alert areas
AreaKindSince 2006Now
River Nene at Billing Aquadrome and nearby business parksWarning area13None
Areas near the Wootton Brook in the Collingtree, Merefield and Shelfleys parts of NorthamptonWarning area8None
Isolated properties and mills near the upper River NeneWarning area4None
Areas near the Dallington Brook and Brampton Branch in NorthamptonWarning area3None
River Nene and tributaries in Northampton, including low-lying areas adjacent to the riverWarning area2None
River Nene upstream of the Northampton Washlands and properties near the Old River Nene in AbingtonWarning area2None
Upper NeneAlert area51None
Minor Tributaries of the Nene in NorthamptonshireAlert area12None

Environment Agency Historic Flood Warnings (first issues only, not updates; “flood watch” counted as an alert before 2011) and the real-time flood-monitoring API. Sign up for free warnings on GOV.UK or call Floodline, 0345 988 1188.

Radon

Parts of Northampton are in radon Affected Areas, up to the Over 30% band

Radon is a natural radioactive gas from the ground; long exposure raises the risk of lung cancer. The atlas gives the chance that a home in each 1 km square is above the UK action level (200 Bq/m³).

SP7058: 1–3% of homes above the action levelSP7059: 3–5% of homes above the action levelSP7060: 5–10% of homes above the action levelSP7061: 5–10% of homes above the action levelSP7062: 5–10% of homes above the action levelSP7157: 10–30% of homes above the action levelSP7158: 1–3% of homes above the action levelSP7159: 3–5% of homes above the action levelSP7160: 10–30% of homes above the action levelSP7161: 10–30% of homes above the action levelSP7162: 5–10% of homes above the action levelSP7163: 5–10% of homes above the action levelSP7257: 10–30% of homes above the action levelSP7258: 10–30% of homes above the action levelSP7259: 10–30% of homes above the action levelSP7260: Over 30% of homes above the action levelSP7261: Over 30% of homes above the action levelSP7262: 10–30% of homes above the action levelSP7263: 5–10% of homes above the action levelSP7357: Over 30% of homes above the action levelSP7358: Over 30% of homes above the action levelSP7359: Over 30% of homes above the action levelSP7360: Over 30% of homes above the action levelSP7361: Over 30% of homes above the action levelSP7362: 10–30% of homes above the action levelSP7363: 5–10% of homes above the action levelSP7364: Over 30% of homes above the action levelSP7365: Over 30% of homes above the action levelSP7456: 10–30% of homes above the action levelSP7457: 10–30% of homes above the action levelSP7458: Over 30% of homes above the action levelSP7459: Over 30% of homes above the action levelSP7460: Over 30% of homes above the action levelSP7461: Over 30% of homes above the action levelSP7462: 10–30% of homes above the action levelSP7463: 10–30% of homes above the action levelSP7464: Over 30% of homes above the action levelSP7465: Over 30% of homes above the action levelSP7554: 1–3% of homes above the action levelSP7555: 1–3% of homes above the action levelSP7556: 3–5% of homes above the action levelSP7557: 10–30% of homes above the action levelSP7558: 10–30% of homes above the action levelSP7559: 3–5% of homes above the action levelSP7560: 10–30% of homes above the action levelSP7561: 10–30% of homes above the action levelSP7562: 10–30% of homes above the action levelSP7563: 10–30% of homes above the action levelSP7564: 10–30% of homes above the action levelSP7565: 10–30% of homes above the action levelSP7654: 10–30% of homes above the action levelSP7655: 3–5% of homes above the action levelSP7656: 5–10% of homes above the action levelSP7657: 5–10% of homes above the action levelSP7658: 5–10% of homes above the action levelSP7659: 10–30% of homes above the action levelSP7660: 10–30% of homes above the action levelSP7661: 5–10% of homes above the action levelSP7662: 10–30% of homes above the action levelSP7663: 10–30% of homes above the action levelSP7664: 5–10% of homes above the action levelSP7665: 10–30% of homes above the action levelSP7755: 1–3% of homes above the action levelSP7756: 5–10% of homes above the action levelSP7757: 5–10% of homes above the action levelSP7758: 10–30% of homes above the action levelSP7759: 10–30% of homes above the action levelSP7760: 10–30% of homes above the action levelSP7761: 5–10% of homes above the action levelSP7762: 5–10% of homes above the action levelSP7763: 10–30% of homes above the action levelSP7764: 1–3% of homes above the action levelSP7765: 5–10% of homes above the action levelSP7857: 1–3% of homes above the action levelSP7858: 3–5% of homes above the action levelSP7859: Under 1% of homes above the action levelSP7860: 5–10% of homes above the action levelSP7861: 5–10% of homes above the action levelSP7862: 5–10% of homes above the action levelSP7863: 5–10% of homes above the action levelSP7864: 5–10% of homes above the action levelSP7865: 5–10% of homes above the action levelSP7957: 1–3% of homes above the action levelSP7958: 10–30% of homes above the action levelSP7960: 5–10% of homes above the action levelSP7961: 5–10% of homes above the action levelSP7962: 5–10% of homes above the action levelSP7963: 5–10% of homes above the action levelSP7964: 5–10% of homes above the action levelSP7965: 10–30% of homes above the action levelSP8060: 10–30% of homes above the action levelSP8061: 1–3% of homes above the action levelSP8062: 10–30% of homes above the action levelSP8063: 10–30% of homes above the action levelSP8064: 10–30% of homes above the action levelSP8065: 10–30% of homes above the action levelSP8160: 10–30% of homes above the action levelSP8161: 5–10% of homes above the action levelSP8162: 10–30% of homes above the action levelSP8163: 10–30% of homes above the action levelSP8164: 10–30% of homes above the action levelSP8261: 10–30% of homes above the action levelSP8262: 1–3% of homes above the action level© OpenStreetMap contributors · BGS/UKHSA
Under 1%1–3%3–5%5–10%10–30%Over 30%
Share of the city’s area in each band
Under 1% of homes1%
1–3% of homes5%
3–5% of homes5%
5–10% of homes30%
10–30% of homes42%
Over 30% of homes17%

99% of Northampton’s built-up area is in a radon Affected Area (1% of homes or more above the action level), and 90% in squares of 5% or more.

The squares are indicative: each takes the highest band found anywhere inside it, so most homes in a coloured square are below it. Only a three-month test in the home gives a real answer.

BGS/UKHSA Indicative Atlas of Radon in Great Britain, version 3. Check an address at UKradon.org.

Neighbours

Flood risk in the places around Northampton

Share of homes at high or medium and at low risk from rivers and the sea. Tap a town for its page.

Moulton: Hazard risk BCollingtree and Milton Malsor: Hazard risk B−Cogenhoe: Hazard risk CKislingbury: Hazard risk CHarpole: Hazard risk ASywell and Overstone: Hazard risk ABlisworth: Hazard risk AMoultonCollingtree and Milton MalsorCogenhoeKislingburyHarpoleSywell and OverstoneBlisworthNorthampton
ABCD
TownPeopleHigh or mediumLowHazard
Northampton243,5270.3%2%B−
Moulton4,9530.1%0%B
Collingtree and Milton Malsor1,5140.3%8%B−
Cogenhoe1,4750.9%3.3%C
Kislingbury1,3231.3%13%C
Harpole1,3490%0%A
Sywell and Overstone1,6360%0%A
Blisworth1,6030%0%A

Kislingbury, 4.2 miles west, has the most homes at risk around Northampton (1.3% at high or medium). Harpole, Sywell and Overstone and Blisworth have none.

Be ready

Get ready for what Northampton faces

Free warnings, what to do in a cloudburst, and what to check before you move.

Get the warnings
  • Sign up free for Environment Agency flood warnings by text, call or email.
  • Floodline: 0345 988 1188, 24 hours.
  • Northampton’s warning areas include River Nene and tributaries in Northampton, including low-lying areas adjacent to the river and River Nene at Billing Aquadrome and nearby business parks.
Sign up ↗
In a cloudburst
  • Surface water rises in minutes, often with no warning issued: stay out of underpasses and dips.
  • Keep the gullies and drains outside your home clear of leaves.
  • Report a blocked road drain to the council.
Radon
  • Test over three months, in a living room and a bedroom.
  • Above 200 Bq/m³, a small sump and fan usually fixes it.
  • New homes in radon areas are built with protection: basic from 3%, full from 10%.
UKradon ↗
Before you buy or rent in Northampton
  • Check the address on GOV.UK’s long-term flood risk service: it gives rivers and sea and surface water separately.
  • Ask whether the home has flooded or had a flood insurance claim; the TA6 property form asks the seller.
  • Homes built before 2009 can get flood cover through Flood Re, the government-backed scheme; newer homes can’t.
  • Check radon for the address on UKradon.org (a small fee) or ask the seller for a test result.
How to read these numbers

What this data can and can’t tell you

  • Defences are counted. Both agencies’ maps allow for flood defences and the chance they are overtopped or fail, so a town behind a defence scheme can show few homes at high risk and many at low risk.
  • Surface water is our estimate. Neither agency publishes a count of homes at risk from surface water, so we read each address on the map. A flat on a hill and a basement in a dip can share a postcode.
  • Past floods are what was recorded. The flood outlines come from surveys, aerial photographs and reports; many small floods, and most surface-water floods, were never mapped.
  • One town, many streets. Risk is street by street. Check a specific address on GOV.UK’s long-term flood risk service before you buy or rent.

Check the long-term flood risk for an address on GOV.UK →

Questions about flooding and hazards in Northampton

Does Northampton flood?

The last flood the Environment Agency recorded inside the city was in January 2004. 0.3% of homes are at high or medium risk from rivers and the sea on the Environment Agency’s maps, which allow for flood defences. About 4% of homes are at high or medium risk from surface water, when heavy rain overwhelms the drains. Northampton grades B− for hazard risk against UK towns.

Which parts of Northampton are at risk of flooding?

From rivers and the sea, the places the Environment Agency warns directly: River Nene at Billing Aquadrome and nearby business parks, Areas near the Wootton Brook in the Collingtree, Merefield and Shelfleys parts of Northampton, Isolated properties and mills near the upper River Nene and Areas near the Dallington Brook and Brampton Branch in Northampton. Surface water can collect in low spots anywhere in the city. Check a specific address on GOV.UK’s long-term flood risk service.

When did Northampton last flood?

The recorded flood outlines inside the city run from 1947 to 2004 (3 years); the largest was in 1998. Flood warnings have been issued for parts of the city since 2006, most recently on 25 November 2024.

Is Northampton at risk of surface water flooding?

About 1.9% of homes are at high risk and 2.1% at medium risk from surface water, against 0.3% at high or medium risk from rivers and the sea. Surface water floods come with little warning, and the agencies don’t issue warnings for them.

Is radon a problem in Northampton?

99% of the city’s built-up area is in a radon Affected Area on the BGS/UKHSA atlas, and 90% is in 1 km squares where 5% or more of homes may be above the action level. Most homes are below it; a three-month test is the only way to know.

Are there flood warnings in Northampton now?

No flood warning or alert was in force near Northampton at 9 November 2026, 11:04. Live warnings are on GOV.UK’s Check for flooding service and Floodline, 0345 988 1188.

Contains Environment Agency information © Environment Agency and/or database right 2026. Contains British Geological Survey materials © UKRI 2026.

Sources: Environment Agency Risk of Flooding from Rivers and Sea, postcodes in areas at risk (June 2026); Natural Resources Wales Flood Risk Assessment Wales (May 2026); ONS Census 2021 households by postcode · Environment Agency Risk of Flooding from Surface Water (NaFRA2, 2025) and Natural Resources Wales Flood Risk Assessment Wales surface water and small watercourses, read at every address (ONS National Statistics UPRN Lookup, September 2026) and weighted by Census 2021 households by postcode · Environment Agency Recorded Flood Outlines and Natural Resources Wales historic flood map, inside the ONS 2022 built-up-area boundary · Environment Agency Hydrology API (daily maximum river level) and flood-monitoring stage scales · Environment Agency real-time flood-monitoring API · Environment Agency Historic Flood Warnings (January 2006 to June 2026) and flood warning and alert areas · BGS/UKHSA Indicative Atlas of Radon in Great Britain, version 3, by 1 km square · TownRatings grades: our own summary of the data, ranked against UK towns only. All under the Open Government Licence v3.0.

Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.