Which? finds potentially unfair storm and flood definitions in home insurance policies

Which? published analysis on 9 April 2025 finding that some home insurers use definitions of "flood" and "storm" that conflict with consumer expectations and industry guidance. The consumer body examined 133 policy documents from 67 insurance firms, using what it described as AI techniques and expert human review¹.

Which? said 32% of policy wording documents contained a definition of "flood" that it considered potentially unfair, and 20% contained a potentially unfair definition of "storm"¹. It tested definitions against guidance from bodies including Flood Re and the Association of British Insurers, alongside survey findings. In a Which? survey of 1,325 UK adults with buildings insurance, 69% defined a flood as an event where water enters and builds up in a home regardless of speed, and 60% defined a storm as some combination of extreme weather conditions¹.

The analysis found 17 of the 42 policies identified as potentially unfair defined flood in terms of the speed at which water enters the home, using language such as "rapidly" and "suddenly", while others explicitly excluded water entering gradually. Over half of policies with potentially unfair storm definitions only covered damage where high winds were involved¹. Separately, 56% of policies contained no definition at all for flood and 32% contained no definition for storm¹.

Policies with potentially unfair flood definitions were sold by three of the 10 largest underwriters by market share: Ageas, Aviva and AXA. Four policies, from John Lewis, Nationwide and Tesco Insurance, had both storm and flood definitions that failed the test¹.

The insurers responded. Tesco said it accepted its wording in relation to floods could be improved and that it was conducting an in depth review of its policy documents. Aviva said it strongly denied any suggestion its policy wording is unfair, stating that it aligns with the definition of flood provided by Flood Re and has been externally tested and benchmarked. AXA said its definition of flood and storm perils was fair and in line with guidance set by independent bodies. Nationwide said flood or storm claims often touch on other areas of its policy that provide cover, and that its claims pay-out rate on flooding and storms outperforms the industry average. Ageas and John Lewis declined to comment¹.

Why it matters for households

Which? said around a third of buildings insurance claims are declined¹. Where a policy defines flood by how quickly water entered a property, or storm by high winds alone, a claim for damage from slow water ingress or from heavy rain without strong wind may fall outside the definition. Policies with no definition at all leave it unclear how an insurer would respond to damage from torrential rain or a rise in the water table¹.

The findings concern home insurance policies already sold by the named providers, so they affect existing policyholders as well as anyone comparing cover. Which? said consumers who believe a claim was unfairly rejected can complain first to the insurer, then to the Financial Ombudsman Service if the complaint has not been resolved within eight weeks¹. Terms that fail the fairness test may also engage the unfair contract terms rules, and the FCA's Consumer Duty requires firms to consider the reasonable expectations of customers¹.

What happens next

The Financial Conduct Authority is conducting a review into how insurers handle claims and is expected to publish its findings later this year¹. Which? called on the FCA to use that review to assess whether firms are complying with their obligations under the Consumer Duty¹.