Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, whether she has considered using multi-year rolling averages to measure progress on reducing storm overflow discharges.

The Environment Agency (EA) considers seasonal variations, including periods of low river flow, when setting and reviewing environmental permits for water discharge and groundwater activities under the Environmental Permitting (England and Wales) Regulations 2016.

Where evidence shows that changing flow patterns, such as more frequent or prolonged low flows, affect environmental risk, the EA can review and vary permits accordingly.

Defra keeps permitting approaches under review, taking account of evolving hydrological data, climate change projections, and wider environmental objectives to ensure permits remain protective, proportionate, and responsive to changing pressures.

The Storm Overflow Discharge Reduction Plan spill frequency targets for storm overflows (ecological, bathing and rainfall targets) are defined as an average over 10 consecutive years. It is recognised that a 10-year assessment requires significant time to determine permit compliance and therefore, to secure early identification of underperforming storm overflows, the EA may use a shorter-term regulatory compliance assessment.