More than 21,000 properties at risk from rivers and surface water. 70,000 more from groundwater. Victorian drainage infrastructure failing the villages built above it. A deep dive into where the flood risk concentrates — and what homeowners are not being told.
Published June 2026 · RISE Flood Recovery Consultancy
Buckinghamshire is not a county most people associate with flooding. It is known for the Chiltern Hills, market towns, commuter villages, and affluent rural communities. It does not appear on the national news the way Somerset or Yorkshire does when waters rise.
But the numbers tell a different story. More than 21,000 properties in Buckinghamshire are at risk from river and surface water flooding right now — and 70,000 more sit in areas at risk of groundwater flooding. Climate change projections suggest those numbers will increase substantially within the lifetimes of people buying homes in the county today.
This article examines what flood risk actually looks like in Buckinghamshire: where it comes from, which areas are most affected, and what happens when the system fails the people living in it.
Buckinghamshire Council's own Local Flood Risk Management Strategy — adopted in December 2024 — sets out the scale clearly.
3,357 properties are currently at risk of fluvial flooding — flooding from rivers overtopping their banks. A further 4,167 properties will move into that risk category under climate change projections.
18,380 properties are at risk of surface water flooding — the kind caused by intense rainfall overwhelming drainage systems. Under future climate change projections, a further 28,702 properties will join them.
70,000 properties across the Chilterns and Thames corridor are in areas at risk from groundwater flooding — water rising from below, driven by chalk aquifers that fill during wet winters and can take months to drain.
Buckinghamshire covers five main river catchments: the Upper and Bedford Ouse, Cherwell and Ray, Colne, Thames and South Chilterns, and Maidenhead and Sunbury. Each presents a different flood risk profile.
The northern part of the county — Buckingham, Tingewick, Gawcott, Thornton, Leckhampstead — sits within the Great Ouse catchment and has experienced repeated surface water flooding events when the drainage system is overwhelmed. In December 2020, 52mm of rain fell within 16 hours, causing widespread flooding across these communities.
High Wycombe and Chesham have both been designated as nationally significant Flood Risk Areas. The River Wye through High Wycombe presents ongoing fluvial risk, while both towns sit in valleys where surface water runoff concentrates rapidly during heavy rainfall.
The Thames corridor — Marlow, Bourne End, Cookham — faces periodic river flooding as the Thames overflows its banks after sustained wet periods. These events are typically well-predicted but no less damaging for it.
Across the Chilterns, groundwater presents the least visible but often most prolonged threat. Properties in villages underlain by chalk can find water rising through floors and walls weeks after rainfall has stopped, as aquifer levels continue to climb.
Much of Buckinghamshire's drainage infrastructure was built in the Victorian era, designed for a county with far fewer properties, far less impermeable surfacing, and a very different climate. The culverts beneath villages that were adequate in 1880 were not designed for modern rainfall intensities or modern development density.
This is not a theoretical problem. The village of Gawcott — recorded in the Domesday Book — has a documented history of surface water flooding. A significant event in December 2020 became the subject of a formal Section 19 investigation by JBA Consulting on behalf of Buckinghamshire Council. The investigation, published in April 2022, identified the Victorian culvert beneath the main road as a primary cause of the flooding. (See the Section 19 Reference Manual for the full statutory framework.)
When further flooding hit the village in June 2023 and again in September 2024, the cause was the same: a culvert system constructed in the 1800s that had never been upgraded to match the growth of the village above it. The drainage infrastructure beneath the community was failing. The community bore the consequences.
Through sustained engagement with Buckinghamshire Council using Section 19 of the Flood and Water Management Act 2010, and through independent drainage investigation and evidence submission, those infrastructure failures were documented, attributed, and ultimately addressed through over £2 million of council-funded works — including the complete diversion and replacement of the culvert system.
That process took years of sustained advocacy. Most homeowners do not know it is possible. That is precisely why RISE exists.
Buckinghamshire Council has committed £10.5 million to its Flood Capital Programme over 2025 to 2027. The programme — which the council confirmed will continue following further funding approval — is expected to reduce flood risk to over 200 residential properties across the county. Projects already in delivery include culvert replacement at Pednormead End in Chesham, watercourse improvements in East Marlow, sustainable drainage retrofits, and flood alleviation works in Sands, West Marlow and Tingewick — that last name a familiar one to anyone who watched the December 2020 floods cut through the northern part of the county.
Project Groundwater, funded by Defra, is working with communities across the Chilterns and Berkshire Downs to improve understanding and resilience of groundwater flooding affecting 70,000 properties.
These are meaningful steps. But public investment in flood infrastructure is reactive by nature — it follows demonstrated harm, not anticipated risk. By the time a scheme reaches the funding queue, properties have already flooded, families have already been displaced, and the damage has already been done. The council itself, in approving the most recent tranche of funding, acknowledged that 2024 was the wettest year on record — and that further heavy rainfall in early 2026 had already caused fresh flooding across parts of the county.
Three things every Buckinghamshire homeowner can do in under thirty minutes — and most never have:
Check your property's flood risk on the updated NaFRA2 data. The Environment Agency's free service at check-for-flooding.service.gov.uk was updated in January 2025 with higher-resolution modelling and the latest climate projections. If you have not checked since then, your property's official rating may have changed.
Look up whether your village or town has a Section 19 investigation report. Buckinghamshire Council publishes its flood investigation reports openly at buckinghamshire.gov.uk/environment/flooding-and-flood-risk-management/flood-investigations. If your area has flooded in recent years, the cause may already have been investigated and documented — and the responsible parties identified.
Sign up to Environment Agency flood warnings. Free, by phone, text, or email. Coverage is limited to main rivers, which means surface water flooding still requires you to read the weather forecast and act on your own observations — but for fluvial risk along the Thames, the Ouse, the Wye and the Chess, advance warning matters.
Sources and further reading: Buckinghamshire Council Local Flood Risk Management Strategy (adopted December 2024); JBA Consulting, Section 19 Flood Investigation Report — Gawcott, December 2020 (published April 2022); Buckinghamshire Council news release on £10.5m Flood Capital Programme 2025–2027; Environment Agency National Assessment of Flood and Coastal Erosion Risk in England 2024 (NaFRA2); Defra Project Groundwater.
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