Infiltration reduction plan

The Environment Agency requires wastewater companies to submit to the EA their plans for managing groundwater infiltration of the sewers in catchments where, due to the high water table following excessive persistent rain, tankers and over-pumps are sometimes used to take away flows and ensure our customers' bathroom, kitchen and toilet facilities are protected.

We're transparent about what we've done and what we plan to do to reduce infiltration and publish approved Infiltration Reduction Plans (IRPs) on our website for all to see. These plans can be viewed below.

The IRPs are living documents, subject to review to take account of, for example, our extensive continuing programme of surveying and sealing the sewers to improve their performance. As such, the Plans only report the work conducted up to their cover dates. Subsequent work will be reported in the updated IRPs.

Before reading our Infiltration Reduction Plans please bear in mind that we are not a flood relief agency. Our task is to maintain wastewater services for customers so, if you have any flooding questions which are not sewer related, please address them to the appropriate authority:

  • County councils are the lead local flood authority for developing strategies to tackle groundwater flooding
  • District and borough councils have powers for managing flood risk from ordinary watercourses
  • The Environment Agency manages flood risk from the sea and main rivers and also monitors the quality of the water course, including the environmental impact of over-pumping.

Infiltration Reduction Plans

Alkham Valley




Goodworth Claitford



Kings Somborne


Lavant Valley


Lower Nailbourne

Pan Parishes


St Marybourne

The Green Southwick

Upper Nailbourne

Winchelsea Beach