Surface water flooding explained: Simon Crowther's BBC Rip Off Britain feature

Written by the FPS Environmental team. Published May 2026.

Simon Crowther, Director at FPS Environmental, was featured on BBC One’s Rip Off Britain on Tuesday 5 May 2026, joining presenter Gloria Hunniford to discuss surface water flooding and the latest Environment Agency mapping. Filmed at Media City in Salford, Greater Manchester, the segment explored how surface water flood risk is rising in urban areas, why the underlying mapping has changed, and what homeowners can practically do to check their own risk.

Simon was invited onto the programme as a flood risk consultant, drawing on his experience advising on UK water and environmental policy through the DEFRA Property Flood Resilience Roundtable, his role in introducing the FloodRe Build Back Better scheme to Parliament in 2022, and FPS Environmental’s wider work supporting homeowners, developers and commercial property owners across the UK whether that be investigating risk, or supporting analysis for development with Flood Risk Assessments and drainage strategies.

A focus on surface water

The Environment Agency’s National Assessment of Flood and Coastal Erosion Risk (NaFRA 2), released in late 2024 and progressively integrated into the Flood Map for Planning during 2025, has fundamentally changed the picture of flood risk in England. The headline figure now sits at around 6.3 million properties in areas at risk of flooding from rivers, the sea or surface water, with approximately 4.6 million of those at risk specifically from surface water, a 43% increase on the previous national assessment.

The shift is partly explained by improved modelling. NaFRA 2 increased the underlying mapping resolution and integrated hundreds of detailed local flood models that were previously held separately. That means many properties now appear at risk for the first time, not because their actual physical exposure has changed, but because the modelling is finally detailed enough to capture flood risk that was always there.

The other part of the picture is genuinely physical. Heavier and more intense rainfall, driven by climate change, is placing existing drainage infrastructure under increasing strain. Many UK drainage systems were designed against the rainfall intensities expected in the twentieth century, and individual storm events are now routinely exceeding what was previously considered the upper end of plausible.

Why surface water risk is different

One of the points Simon made on the programme was that river flooding tends to be confined to the floodplain, the corridor of land alongside a watercourse where water has historically been able to spill during a flood event. That makes river flood risk relatively predictable. Properties inside the floodplain are at risk; properties outside it are usually not.

Surface water flooding behaves very differently. It happens when rainfall cannot drain away quickly enough, either because drainage networks become overwhelmed, because ground conditions prevent infiltration, or because water runs off impermeable surfaces and accumulates in low points. Surface water flooding can affect properties well outside any river floodplain, and it can affect properties that have no recorded history of flooding whatsoever.

That makes the picture much harder to navigate for homeowners and prospective buyers. A property might sit comfortably in Flood Zone 1, the lowest fluvial and tidal risk category, and still be at significant risk from surface water, particularly in dense urban areas where impermeable surface coverage is high and drainage capacity is limited. The Environment Agency has identified that around three times as many properties are now at high risk from surface water than from rivers and the sea, which underlines just how significant this shift has become.

The cumulative risk picture

Flood risk is often described in the news using terms like “one in a thirty year” or “one in a hundred year” floods. These are statistical return periods, and they are widely misunderstood. A 1 in 100 year event does not mean one event every hundred years on the dot. It means a 1% annual probability, every single year, regardless of whether one has just happened.

For homeowners, the more relevant question is the cumulative probability over the period they expect to live in their property. A property at 1 in 30 year risk has approximately a 49% chance of flooding at least once over a 20-year period, rising to roughly 64% across a 30-year mortgage term. A property at 1 in 100 year risk has approximately a 22% chance over 20 years and around 26% over a 30-year mortgage. Even a 1 in 1000 year rated property has a 2% cumulative risk over 20 years, small but not zero, and the calculation shifts further as climate change is factored in.

What homeowners can practically do

The first step Simon highlighted on the programme is for homeowners to check their property’s flood risk using the relevant government website, which varies by UK nation. In England this is the Environment Agency’s “Check the long-term flood risk” service at gov.uk/check-flooding. In Wales the equivalent service is run by Natural Resources Wales, in Scotland by the Scottish Environment Protection Agency, and in Northern Ireland by the Department for Infrastructure.

The official mapping is a useful starting point but not a complete answer at the property scale. The Environment Agency itself acknowledges that surface water mapping should be used as a broad indicator rather than a substitute for site-specific assessment. The mapping cannot capture the influence of local drainage assets, the precise topography of an individual property, or the way exceedance flows route through a particular street or layout. For homeowners who identify their property as potentially at risk, a more detailed assessment is usually the next step.

For homeowners who are concerned about the risk to their property, FPS Environmental delivers Property Flood Resilience surveys aligned with the CIRIA C790 Code of Practice, providing a clear assessment of how water might enter a property and what resistance and resilience measures would be most effective. For prospective buyers considering a property purchase, our Homebuyer Flood Risk Report provides a property-specific assessment of current and future flood risk, alongside the resilience measures that may help support insurability and mortgageability over the long term.

The Build Back Better scheme

For homeowners whose properties are at risk and who are insured, the Build Back Better scheme offers an additional layer of support. The scheme, run by Flood Re in partnership with participating UK insurers, allows policyholders to claim up to £10,000 in addition to the cost of repairs after a flood, specifically to make their property more resilient to future flooding. The funds can pay for measures including raised electrical sockets, flood doors, self-closing air bricks, sump pumps, waterproof surfaces and similar resilience interventions.

Simon was directly involved in the launch of Build Back Better, presenting the scheme at Parliament in 2022 to MPs and industry stakeholders. The scheme is now offered by an expanding group of UK insurers, and Flood Re actively encourages homeowners to ask whether Build Back Better is included in their existing or future home insurance policy.

Filming at Media City

The location of the broadcast itself is a useful illustration of the principles being discussed. Media City sits in Salford, Greater Manchester, immediately alongside the River Irwell and Manchester Ship Canal in an area that has been substantially redeveloped over the past two decades from former industrial dockland. The site is in a part of Greater Manchester where surface water flooding has been a recognised concern, with combined drainage networks managing rainfall across dense impermeable surfaces and the underlying topography channelling runoff toward the Irwell corridor.

Greater Manchester more broadly is one of the regions where the post-NaFRA 2 picture has shifted most visibly. The combination of post-industrial redevelopment, dense urban form and increasingly intense rainfall has placed real strain on drainage systems that were not designed for current conditions. FPS Environmental delivers Flood Risk Assessments and Property Flood Resilience surveys across Manchester and the wider North West, working with developers, homeowners and commercial property owners on sites where surface water risk is now a primary consideration.

The wider picture

The increase in surface water flood risk identified through NaFRA 2 is unlikely to be a one-off shift. Climate projections suggest that by the middle of this century, around one in four properties in England could be in an area at risk of flooding from one or more sources, with surface water continuing to expand as a proportion of overall risk. The combination of intensifying rainfall, ageing drainage infrastructure and continued urban expansion is making proper, site-specific flood risk assessment more important than ever.

Simon’s appearance on Rip Off Britain reflects FPS Environmental’s wider position as a recognised media expert on flooding. Simon has been featured on BBC, Sky News, Channel 4 and other national broadcasters discussing flood risk, climate change adaptation, and the practical steps homeowners can take to protect their properties.

The Rip Off Britain segment featuring Simon Crowther is available on BBC iPlayer.