| 18 Jun 2026
Split incentives in property-level flood adaptation across households, insurers and government in the Netherlands
Abstract. Flood adaptation can be organized across multiple spatial scales, from national flood defences to individual buildings. Property-level risk estimates drive household adaptation decisions. Yet for the Dutch housing stock, how flood risk concentrates, distributes across stakeholders, shifts under methodological uncertainty, and translates into adaptation budgets remains unquantified. For 12,992 embanked Dutch residential properties, we combine precipitation and flood defence failures across two hazard and two vulnerability approaches for 2025 and 2050. Flood damage is sharply concentrated, with the top 5 % of properties carry more than half of expected annual damage. The stakeholder split also shifts over time. In 2025 government bears 56 % of damages, insurers 32 % and households 12 %; by 2050 this becomes 13 %, 72 % and 15 %. The three-stakeholder coalition budget exceeds the household-only budget by an order of magnitude, so co-financing across stakeholders could help close the split-incentive gap. These stakeholder patterns hold across hazard and vulnerability methods, yet per-property budgets vary by an order of magnitude. These findings connect two debates usually held apart, on the credibility of property-level flood risk estimates and on how to finance adaptation under a split-incentive. Both bear on how such estimates should inform flood adaptation decisions.
Competing interests: Cees Oerlemans is affiliated with HKV, and Matthijs Kok was previously affiliated with HKV. The study uses the MijnWaterRisicoProfiel API, developed by HKV, and evaluates the BREACH method, developed by researchers holding both academic and HKV affiliations. HKV had no role in the study design, analysis, interpretation, or decision to publish, and the analysis was conducted independently. The remaining authors declare no competing interests.
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