PPS 15 Planning and Flood Risk (Revised)·Page 41·6.38
Surface water flooding risk and development management
Development at risk from surface water flooding can be permitted if a drainage assessment demonstrates that flood risk can be effectively controlled and mitigated without creating greater flooding risk elsewhere. Developers should consider alternative sites where there is a history of recurrent flooding.
The approach adopted in PPS 15 to the management of development likely to be at risk from surface water flooding is to facilitate development provided that the drainage assessment demonstrates that the flood risk can be effectively controlled and mitigated and that it will not create greater potential for surface water flooding elsewhere. However, adequate control and mitigation may prove difficult and expensive in locations where there is a history of recurrent flooding and in such circumstances it would be prudent for the developer to consider an alternative site.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/PPS 15 - Planning and Flood Risk (Revised).pdf