Raw sewage discharge must stop. change is overdue.
the history
UK Water legislation did not apply to the Isles of Scilly until ‘The Isles of Scilly (Application of Water Legislation) Order 2020’ came into force. South West Water took responsibility from the Council of the Isles of Scilly, and became the provider for water services across the islands. They were granted a Local Enforcement Position for sewage up to 2025 - a temporary permission to operate unlawful infrastructure - whilst they brought the system up to regulatory standards though targeted investment.
At their appointment, St Mary’s had sewage treatment facilities on-island capable of secondary treatment and UV disinfection for some of the islands’ sewage, but these were not well-maintained by SWW. Initially a long sea outfall pipe discharged all of Hugh Town’s raw sewage far offshore, along with the treated sewage from the remainder of the island, into a powerful tidal area, but that pipe broke many years ago. Now no sewage is treated. All of St Mary’s raw sewage, along with septic tank contents, is discharged through the Morning Point outfall close to shore. Not in a storm, not just in emergencies, but every fifteen to sixty minutes.
Everyone agrees that this must stop. Environment Action Scilly is strongly in support of change, investment and improvement to our sewage and drinking water infrastructure, because everyone deserves clean water.
Where we are now
In previous publications and business plans, South West Water promised to invest and bring the sewage system in line with Urban Waste Water Treatment Directive (pg.10, note.2); SWW said they will protect our environment by providing secondary treatment with a future-proof system capable of managing the substantial seasonal population increase and new property additions. These promises are reiterated across multiple documents and webpages they’ve provided to the community and their wider customer base.
In 2026, a new proposal appeared. It was to replace the ineffective secondary treatment plant with a screening plant and new long sea outfall, which would discharge screened but untreated sewage into marine protected areas. Again, not in a storm. Not only in an emergency. All the time.
Proposals were being rushed through the regulatory processes, with little evidence or accountability to the community up to 15th July 2026. The Environment Agency informed residents that a permit application had been made to the Environment Agency, but had not disclosed this until the community made a substantial number of inquiries. We are calling on them to reject applications that include anything less that secondary treatment with UV disinfection, as is the process for mainland wastewater sites. Since the EA’s update, South West Water has amended their proposal page to state that, following engagement with the community, they have revised their proposals to include secondary treatment.
South West Water is a very experienced organisation with ample resources and full understanding of their obligations and the law. We are glad that SWW have acknowledged some of our community’s concerns, but secondary treatment alone is not enough of an improvement. We will continue our campaign and call for UV disinfection and will maintain public scrutiny to ensure that new proposals are suitable, that evidence is robust, and that there are no more broken promises. We are concerned that it was publicity and not their pre-existing knowledge of the law that has led to this change of direction.
We will continue to ask for evidence that supports legality, environmental impact, and considers drinking water quality due to the nearby desalination plant, which tops up St Mary’s’ drinking water supply. We’ve also asked why previous plans have been abolished and will ask why SWW made an unlawful proposal in the first place. What led South West Water to act as they have, and how will they restore the community’s trust?
You can help us campaign for equal treatment with our mainland friends and call for secondary treatment with UV disinfection.
