Skip to main content

In this page


To drive the delivery of evidence-based catchment solutions, better information is required about discharge quality from overflows and the impact on the receiving water quality. Improved effluent monitoring at targeted sites, together with event duration monitoring already in place, will enhance evidence available and enable effective targeting and prioritisation of action. Current and future overflow monitoring must also work in parallel with monitoring programmes for pollution sources from agriculture, diffuse and other sectors.

An investigative monitoring programme will be established between the NRW and the water companies to determine long-term requirements for monitoring overflows throughout Wales. The need to monitor for a wider range of pollutants including micro plastics, pharmaceuticals, and public health parameters will also be assessed. 

Water companies will also investigate and promote the use of monitoring and evidence from other sources including innovative solutions and technology. Citizens and local groups can play a key role in helping tackle water quality pollution through providing monitoring intelligence and public awareness. We will actively work with citizen scientists to understand how their work forms part of our final work programme. 

Our commitments

The actions being taken forward within this workstream are all aligned to the Welsh Government Programme for Government 2021-26 and the Wellbeing goals of:

  • Building a stronger, greener economy as we make maximum progress towards decarbonisation.
  • Make our cities, towns, and villages even better places in which to live and work.
  • Embed our response to the climate and nature emergency in everything we do.
  • Begin to designate Wales’ inland waters for recreation, strengthening water quality monitoring.
Lead Organisation     Action    Why?     By When
Natural Resources Wales   We will undertake a review of all evidence both within Wales, the UK and from wider sources to develop an evidence programme for storm overflows      To design and understand an evidence programme we first need to analyse and review current best practice, evidence and monitoring available to help us set the parameters for future monitoring.     December 2022
Natural Resources Wales Building from the review and working with the taskforce we will build an evidence programme that works alongside the evidence programmes of the Water Companies in Wales, identifying the parameters required to achieve better water quality.     Targeting evidence gathering at key high spilling assets and assets in sensitive locations, aligned to water company monitoring of assets will enable us to build a picture of the impact presented from storm overflows.    Instigate an evidence programme from April 2023
Natural Resources Wales We will undertake local ‘bankside’ surveys (invertebrate assessment comprises of a 1-minute sample that looks at the different habitats within the survey area) at agreed locations to assess the biological impact of storm overflows, targeting areas of stakeholder concern as well as identified high spilling assets.          When overflows operate under the correct conditions any impact on the environment should be negated. Our surveys will help develop a picture of river health against the backdrop of storm overflows We will look to carry out a 2-year programme of investigation between 2022-2024 to ensure we take account of weather and seasonal patterns.
Taskforce We will develop a Framework for the use of ‘Citizen Science’ and stakeholder evidence in identifying and tackling storm overflow issues.      The public, stakeholders, and customer role in improving water quality is vital to its success. The taskforce will help develop a framework for where others outside of the regulator and water company can help develop evidence and provide a pivotal role in identifying and improving any poorly preforming assets.  Working with stakeholders will aim to develop and publish a framework by July 2023 that can work  alongside the evidence base of Regulator and Water Companies.
DCWW Building on the data we already publish on our website from our Event and Duration Monitors (EDM), we will develop a more user-friendly interface. Following on from our provision of data to Surfers Against Sewage for real time alerts for Bathing Waters, we will ensure we have a real time monitoring system, which will report within 1 hour of discharge, installed across our asset base.       To increase the openness and transparency of our environmental data to the public  The mapped interface tool will go live in September 2022
A Real time monitoring system will be implemented by March 2025
DCWW We will build an online portal which will allow us to share all information we gather on the ecological impact from storm overflows.     To increase the openness and transparency of our environmental data to the public  Information portal will be implemented by March 2025.
DCWW/HD  We will assess all riverine storm overflows for environmental impact        To fully understand the impact of storm overflows on the environment. Full assessment of impact from all storm overflows by December 2027.
HD    Making sure performance information is easily accessible via our website by end of 2022 so that people have greater confidence about the opportunities to enjoy the rivers across our region.     To increase the openness and transparency of our environmental data to the public   By the end of 2022
CCW/Afonydd Cymru We will further consider existing (CCW) Wales specific evidence on public awareness of river water quality to help identify engagement gaps that would inform how we enhance public and stakeholder understanding on the issue of overflows in Wales.  

Work with water customers to tackle sewer misuse.  Work with the public and stakeholders to improve their understanding and active role in addressing the issue sewer blockages and overflows in Wales    December 2022
CCW   We will set a benchmark for the link between personal behaviours and the impact on the environment, and the target for 2030.     
Assess and provide evidence of changes to people making the connection between their use of wastewater services and its impact on the environment (CCW Water awareness annual research).  October 2022 Ongoing annual survey
CCW   We are reviewing the clarity and transparency of water industry environmental information on company and other spaces      Increasing water company environmental information transparency and accountability on their environmental impact to increase public trust   December 2022