Guernsey Water completes major upgrade of Mill Street and Mansell Street water main

Guernsey Water has completed the replacement of the ageing water main beneath Mill Street and Mansell Street, the first major capital investment project of 2026, and a significant early milestone in the utility’s long‑term plan to renew Guernsey’s essential water infrastructure. The previous main, installed in 1946, had burst twice in 2025, including one incident that flooded a local business, resulting in its prioritisation for renewal.

The project began on 2 January. Teams from local contractors Geomarine and Tarmac Services carried out excavation and reinstatement in sections, installing temporary overland pipework to maintain water supplies throughout. Thousands of paving stones and deep granite cobbles were hand‑lifted, cleaned and reinstated to enable safe access to the pipe below.

In total, 300 metres of the old cast‑iron main were removed and replaced with a larger, more durable plastic main designed to meet demand for decades to come — futureproofing water supplies in the area for the rest of the century. This follows months of steady progress, despite the exceptionally wet start to the year – with the wettest February since 1976.

Capital Delivery Manager Carl Falla said:

“This is the first major capital project of the year and will ensure a sufficient and resilient water supply for residents and businesses in that part of St Peter Port for the rest of the century. This year we are spending £7.8m on upgrading ageing water and wastewater systems, all part of our wider investment programme.

“I want to thank those who live and work in the area for their patience while we undertook this project. Proactive, planned works are always preferable to emergency repairs. This more durable plastic main will reduce the need for emergency interventions in the future.”