Latest update – 23rd September 2026
We're continuing to progress plans to improve drinking water infrastructure across the Isles of Scilly and will be carrying out a programme of surveys and investigations between September and November 2026.
This programme includes investigations to support a proposed new water main connection between Telegraph and our existing site at Old Town on St Mary's, as well as surveys across the islands to inform future investment in the water network.
The works will help us better understand ground conditions, environmental constraints, and infrastructure requirements across the Isles of Scilly. The information gathered will support the design and development of future improvements to the water network.
Most of the work is investigatory and disruption is expected to be minimal, although residents may notice South West Water teams and specialist contractors carrying out surveys, environmental walkovers, and other assessment work in several locations across the islands.
Some temporary traffic management may also be required, and we will give those affected plenty of notice.
The timing and locations of these activities are subject to survey findings and the relevant approvals.
What we're doing
We’re reviewing our plans to ensure the right long-term solutions are delivered for the Isles of Scilly.
Currently, we’re working on updated proposals for the drinking water programme, and we will share more details later this year.
Our drinking water plans focus on delivering a continuous supply of wholesome water for all islands.
- To improve water quality across all islands
- Make water supplies more reliable and better prepared for the future
- Support future growth, including new homes and increases in visitors.
Programme of works
| Date | Activity |
|---|---|
| Tuesday 1 September to Friday 3 October 2026 | Telegraph to Old Town investigations, St Mary's
Trial holes will be carried out using mini diggers and hand tools to help confirm ground conditions and support the design of a proposed new water main connection. Temporary traffic management may be required. |
| Monday 21 September to Monday 12 October 2026 | Non-intrusive geophysical surveys, St Mary's, Bryher and St Martin's
Survey teams will assess ground conditions and gather information to support future infrastructure design, including potential beach well intake locations. Residents may see teams travelling between sites in vehicles and working along footpaths. There will be no traffic management required. |
| Mid-October to November 2026 | Ground investigations on all five islands' beaches
Trial pits and boreholes will be used to gather more detailed information about local ground conditions. The exact locations will be confirmed following the initial survey work. |
| Mid-October to November 2026 | Environmental and marine surveys on all five islands
Habitat, heritage, intertidal and marine surveys will help us understand local environmental conditions and inform future project design. These investigations are non-intrusive, but residents may notice survey teams working across the islands. |
What’s happened since the last update?
Since Summer 2024, we’ve reviewed earlier proposals and found these didn’t provide the right long-term solution for the Isles of Scilly.
We are continuing to work with our partners and regulators to deliver interim improvements, these are:
- St Mary’s - new UV disinfection system
- St Martin’s - new pipeline
- Tresco - new UV and enhanced treatment
This allows us more time to assess the options available; we’ll share more details with you later this year.
If you have enquiries please email our dedicated inbox - iosproject@mm-b.co.uk
Isles of Scilly Wastewater
Read about our proposals to improve wastewater services on the islands.
