Water companies: environmental permits for storm overflows and emergency overflows

How to control intermittent storm discharges from combined sewer overflows and waste water treatment works, and minimise the risk of emergency sewage discharges from sewage pumping stations.



This guide is to help water companies submit appropriate permit applications for storm overflows and emergency overflows.

Discharges of storm sewage and sewage in an emergency must be authorised by an environmental permit.

This guide explains:

  • how to classify storm overflows
  • water quality, aesthetic control and design standards for storm overflows
  • monitoring and reporting requirements for storm overflows
  • requirements for new or improved emergency overflows
  • what to include in your permit application
  • when the Environment Agency will issue a permit
Published 8 May 2018
Last updated 13 September 2018 + show all updates
  1. Updated the section on 'Shellfish waters: environmental quality design standards' to include the new geomean standards.
  2. First published.