New Homes in Flood Risk Areas: What the Numbers Actually Say

About one in nine new homes built in England between 2022 and 2024 stands in an area at medium or high risk of flooding. The government says more than 99% of new homes proposed in planning applications comply with Environment Agency flood risk advice. Both statements are true. The gap between them is where most of the argument about new homes in flood risk areas goes wrong, because the two figures are counting different things and are routinely quoted as though they were counting the same thing.

This article sets out what each headline figure measures, how much of the apparent rise is a change of definition, what nobody counts at all, and what any of it means for a specific site. If you are already at that point, our consultants prepare a flood risk assessment for planning that answers the site question rather than the national one.

The two headline figures in this debate answer different questions, and neither of them measures how many new homes will actually flood.

How many new homes in England are built in flood risk areas?

Aviva's February 2026 analysis found that 43,937 of the 396,602 new homes built in England between 2022 and 2024, or one in nine, sit in areas at medium or high flood risk. A further 26% carry some level of risk. Aviva projects that 15% of the homes built in that window will be at medium or high risk by 2050.

The method combined Ordnance Survey AddressBase new-address records with the Environment Agency's NaFRA2 risk data, reported at constituency level. Concentration is uneven. Greater London and Essex show 32% of new homes in medium or high risk areas; the West Midlands shows 3%, and the East of England 2%. Read those numbers carefully, because a constituency-level figure tells you that a new address sits inside a risk band drawn at national scale, not that the plot it stands on floods, and on a large site the difference between one end of the red line and the other can be the difference between a mapped risk band and none at all. Scale matters here.

Set that against the delivery backdrop. England added 208,600 net additional dwellings in 2024-25, down 6% on the previous year, against a target of 1.5 million over the Parliament. Roughly 392,400 had been delivered by mid-June 2026. That is around a quarter of the target, about a third of the way through.

Why the government says 99% of new homes comply with flood risk advice

The Environment Agency publishes how many homes were granted planning permission against its sustained flood risk objection. In 2024-25 that number was 301. Across the nine years from April 2016 to March 2025 it was 2,950. The Agency responded to 8,292 planning applications in 2024-25 and gave detailed flood risk advice on 5,742 of them. More than 96% of decisions, and more than 99% of the new homes proposed, complied with that advice.

Around 55,000 homes were kept out of unsafe locations, or out of unsafe layouts, over that same year. On its own terms the system looks like it is working. The measure was designed to test whether planning authorities take the statutory consultee's advice, and on that narrow question the answer has been a consistent yes for the better part of a decade. It is a fair measure of one thing and silent on another.

2,950 homes were permitted against Environment Agency flood risk advice in nine years. England adds that many to its housing stock every five days.

When MHCLG responded to the Aviva research in February 2026 it used those figures, and added that the analysis "doesn't even factor in flood defences currently in place". A fortnight later, in a Lords debate on new housing and flood risk, the housing minister repeated the 96% and the 99% and accepted that meeting the housing target means using some flood risk land, with mitigation as the safeguard.

Edward Bouët, a director at Unda and one of the consultants who writes the advice these figures are counting, is blunter about what the number covers:

That is the whole disagreement in one paragraph. Both sides are describing the same planning system, and neither of them is lying about it.

Both figures are true. Here is what each one measures

The 301 counts decisions in which a planning authority overrode a sustained Environment Agency objection. The 43,937 counts new homes whose location falls inside a flood risk band. A scheme can sit in Flood Zone 3, satisfy the Environment Agency completely, and appear in the second number while being entirely absent from the first. The two figures were never measuring the same thing, so quoting one against the other proves nothing either way.

There is a further wrinkle in the government's defence of its record. NaFRA2 risk categories for rivers and the sea do account for defences, so "ignores the defences" does not hold across the whole dataset. It has real force for the surface water component, which is largely undefended, and where the risk shown on the map is closer to the risk a household would actually experience than it is for a defended reach of river, because there is usually nothing between the rainfall and the property except the drainage network and the ground. Surface water accounts for 4.6 million of the 6.3 million properties at risk in England.

From one in thirteen to one in nine: how much of the rise is real?

Aviva's earlier study, published in January 2024, put 8% of new homes in flood zones. That figure measured National Flood Zone 3 only: rivers and sea, undefended. The 2026 figure measures NaFRA2 medium and high risk from every source, surface water included. Part of the move from 8% to 11% is a change of definition and dataset rather than a change in what developers are doing. Broadening the denominator to include surface water was always going to raise the headline percentage, because surface water risk is far more widely distributed across urban England than fluvial and tidal risk are, and it reaches sites that no flood zone has ever touched. The comparison is not like for like.

That does not make the trend imaginary. NaFRA2 is a better model than the one it replaced, and what it shows is uncomfortable: 6.3 million properties in England in a flood risk area now, rising to around 8 million by mid-century, roughly one in four. But the honest version of the headline is that the measurement improved at the same time as the exposure grew, and nobody has separated the two effects.

Anyone quoting the rise from one in thirteen to one in nine without saying that the definition changed is overstating it.

What the numbers do not count

The published statistics on new homes in flood risk areas stop well short of the question that matters. Nobody counts how many new-build homes have actually flooded, and nobody counts how many planning appeals turn on flood risk. Four gaps sit under this argument. One of them opened up in the last year.

• Partial outcome coverage. The Environment Agency records the planning outcome for only around 68% of the applications it was consulted on across the nine-year dataset. The 301 is a floor, not a count.
• A measure quietly dropped. The Agency's quarterly corporate scorecard reported local authority compliance with its flood risk advice up to 2024-25. That measure is absent from the 2025-26 scorecard, with no published explanation.
• No appeal breakdown. The Planning Inspectorate publishes appeal volumes and outcomes but not the reason for refusal, so no official figure exists for appeals decided on flood risk grounds.
• No flood register. Nobody counts new-build homes that have subsequently flooded. Where individual cases have been documented, it has been by journalists rather than by any statutory body.

That last gap is the one that should worry people, because a flooded new-build is the outcome the whole system exists to prevent. Parliament's Environmental Audit Committee noted cases in October 2025 of new developments flooding more than once within a year, and could not quantify them nationally. Our own explainer on why schemes are approved despite local flooding objections covers the enforcement side of that gap in more detail.

Parliament has asked for exactly that check. The Environmental Audit Committee recommended post-construction inspection of drainage schemes in October 2025; the government's response two months later offered to explore stronger adoption and maintenance arrangements instead of commencing Schedule 3 of the Flood and Water Management Act 2010. So the gap stays open.

What the August 2026 NPPF changed about where homes can go

The National Planning Policy Framework published on 17 August 2026 gives flood risk its own chapter for the first time. Chapter 18 carries Policies F1 to F9, and the flood zone definitions and the vulnerability matrix move out of guidance and into the Framework itself, at Annex F. The tests survive intact: the sequential test at Policy F5, the exception test at Policy F6, and safety for the development's lifetime at Policy F7. Our full breakdown of the August 2026 changes works through the detail clause by clause.

Two changes bear directly on this argument. The old wording that development "should not be allocated or permitted" where lower-risk alternatives exist has gone; Policy F5 now says such proposals "should not be located" in areas at risk. The consultation document was explicit about why, saying that it may still be appropriate for development to proceed in those circumstances when weighed against other considerations, provided the remaining tests in the chapter are satisfied and the scheme would be safe for its lifetime. That is a smaller change on the page than it is in practice, because the earlier phrasing gave an objector a clean line to argue that a failed sequential test ended the matter, whereas the new one puts flood risk back into the balance alongside housing land supply, deliverability and everything else a decision-maker is weighing. And the surface water exemption from the sequential test, previously guidance only, is now written into Policy F5.

Seventeen insurers, lenders and flood bodies wrote to ministers in March 2026 opposing that exemption. It went ahead. The courts have moved the same way: the Gladman judgment in January 2026 confirmed that a missing sequential test is a matter for the planning balance rather than an automatic refusal. Where a scheme now needs one, a sequential and exception test report is the document that has to carry the argument.

Do flood defences close the gap?

Not on the current arithmetic, and that matters because the case for consenting new homes in flood risk areas often rests on defences that are still to be built. The government has committed £7.9 billion of capital over the decade to 2035-36, with £1.4 billion allocated for 2026-27 across more than 600 schemes, and expects 840,000 properties to benefit by 2036. Against approximately 6.3 million properties at risk, that is about one in eight. The funding rules changed in April 2026 as well, which makes small and medium schemes far easier to get built.

Behind that headline the existing estate is thinner than it looks. In April 2026, 93% of high-consequence flood risk assets were at their required condition, which met the target. The Agency's own optimum is 98%, and 98% is what the estate achieved in 2018-19. Parliament put the shortfall at roughly 200,000 properties receiving less protection than the asset register implies.

None of that is an argument against the investment, which is the largest programme England has run. It is an argument against treating a defence commitment as a reason to allocate land. The defence is a decade away. The permission is not.

What this means if you are promoting, buying or assessing a site

The national statistics settle nothing about a particular site, and were never designed to. They are an argument, not a diagnosis. What decides whether a scheme is consentable and safe is site-specific evidence: which sources of flooding reach the land, what the levels are now and across the development's lifetime, whether safe access and escape work in a real event, and whether the surface water drainage strategy returns water at a rate the receiving system can take.

Which is why the sequential test argument and the drainage design are the two places a scheme is actually won or lost, and why both of them turn on evidence a national dataset cannot see.

The consequence that follows a household rather than a planning file is insurance. Flood Re, the scheme that keeps flood cover affordable for high-risk homes, has never covered properties built after 1 January 2009, and it is due to end in 2039. Every one of the 43,937 homes in Aviva's count sits outside it by definition. That is how flood risk reaches mortgages, insurability and resale value, and none of it shows up in a planning statistic.

Frequently asked questions

If you are working on a site where flooding is in play, whether that is a promotion, a purchase or an application already at validation, our chartered flood risk consultants can tell you where you stand. Call 01293 214444 or email enquiries@unda.co.uk, or start with a flood risk assessment for planning.