Guidance review on storm overflows brought forward

News Release

Environmental Standards Scotland welcomes the Scottish Government’s commitment to bring forward review of guidance on storm overflows

Environmental Standards Scotland (ESS) has welcomed a commitment by the Scottish Government to review existing guidance on the definition of the exceptional circumstances in which it is permissible for storm overflows to spill in Scotland.

In a letter to ESS, the Cabinet Secretary for Net Zero and Energy confirmed that this decision was taken in “recognition of the ESS request” to reconsider their position on this matter.

A previous statement from the Cabinet Secretary had said that the Scottish Government was assessing the European Union’s Urban Wastewaster Treatment Directive and planned to bring forward revised legislation concerning the operation of storm overflows as part of that process. However, ESS asked the Cabinet Secretary to reconsider updating guidance on the existing legislation, given concerns that revised legislation would take a significant amount of time and would result in an unacceptable delay and lack of clarity.

Chief Executive of ESS, Mark Roberts said: “We have been clear that guidance in Scotland about the exceptional circumstances in which it is permissible for storm overflows to spill is outdated and is unclear that spills should only occur in exceptional circumstances.

“There is a high level of public concern on the operation and management of storm overflows in Scotland. That’s why we welcome this change of course from the Scottish Government to now look at how the guidance on exceptional circumstances can be updated without waiting for changes to be made to legislation that may take years to be finalised.

“ESS will continue to monitor and report on the delivery of this commitment.”

Storm overflows are part of the sewerage system and are designed to reduce the risk of sewers flooding homes and businesses. However, spills from storm overflows can pose a risk to the environment and to human health. The Scottish Government, Scottish Water and the Scottish Environment Protection Agency (SEPA) all have responsibilities in relation to the storm overflows in Scotland.

In response to a separate ESS recommendation that called for greater information and transparency on storm overflows, Scottish Water launched an overflow map in December 2024 showing real-time data from overflows across Scotland.

ENDS

Notes to editors:

i) You can read the letter from the Cabinet Secretary to ESS confirming the decision to bring forward the review of the guidance here

ii) You can read the letter from ESS to the Cabinet Secretary requesting that the guidance is updated sooner than the Cabinet Secretary previously committed to doing so here

iii) You can read the initial letter from the Cabinet Secretary to ESS stating that the Scottish Government will update the guidance as part of assessing the recast Urban Waste Water Treatment Directive here

iv) The Urban Waste Water Treatment (Scotland) Regulations 1994 and ‘exceptional circumstances’.

The Scottish regulations controlling waste water treatment (the Urban Waste Water Treatment (Scotland) Regulations 1994) derive from the 1991 European Urban Waste Water Treatment Directive. The Regulations require Scottish Water to ensure that sewerage systems, including storm overflows, meet the requirements of BTKNEEC (best technical knowledge not entailing excessive costs) to limit pollution. In addition, the Regulations require, when read together with the objectives of the Directive and decisions from the European Court of Justice, that under normal climatic conditions and taking into account seasonal variation, all urban waste water is collected and treated, except in exceptional circumstances. The Scottish guidance on this was last updated in 1998 and ESS finds that it fails to reflect the requirement for spills from storm overflows to be exceptional. This has had consequences for Scottish Water’s operations and SEPA’s regulatory activity and limits effective implementation and application of the law (see paragraphs 7.1 – 7.12 of the report).

v) You can read ESS’ full report on storm overflows that was published in September 2024 here. The report made six recommendations to the Scottish Government, Scottish Water and SEPA. Recommendation 3 was in relation to guidance on the exceptional circumstances in which it is permissible for storm overflows to spill:

Recommendation 3: The Scottish Government should as a matter of priority: (1) prepare and publish up-to-date, clear and specific guidance about the

exceptional circumstances in which it is permissible for storm overflows to spill; (2) ensure this guidance takes into account predicted future climatic conditions (commissioning further research if required); and (3) provide up to date information on BTKNEEC requirements.