'Significant investment', including more than £34 million over the next four years, is needed to upgrade the island's ageing sewage system to avoid 'catastrophic failures'.

A new report looking at the state of Jersey's liquid waste system has found that the 1950s-built infrastructure is struggling to cope with a population that is now more than double the size it was designed for.

Despite a new £83.2 million treatment centre at Bellozanne, set to be finished by the end of this year, its handling capacity will be restricted because of the outdated wider network.

Infrastructure Minister Deputy Tom Binet says the system is usually overlooked by islanders.

"It's only noticed when something goes wrong. The island has been well-served by the current sewerage infrastructure, but it is ageing, and we now need a significant investment for the future of the island."

The report says that without upgrades to the network of 109 sewage pumping stations and rising mains, the ageing infrastructure could prevent the government meeting its target of building nearly 8,000 new homes by the end of the decade.

"Clearly, house building on this scale and programme is a challenge in itself in the context of Jersey, but the impact of large estates on the existing liquid waste system with its existing limitations is potentially catastrophic."

 The Bellozanne Sewage Treatment Works is due to be completed this year.  Credit GoJ.

The 220 page Bridging Liquid Waste Strategy considers what must be done, and where, to make improvements.

The Bonne Nuit treatment station and First Tower rising main are among the top priorities, with upgrades to them earmarked by 2026.

Other locations identified are Le Dicq, Maufant, West Park, St Brelade, Greve de Lecq, Maupertuis, St Peter, Beaumont, Grouville and Le Hocq.

Deputy Binet says that he is in talks with the Treasury Minister, Deputy Ian Gorst, about the 'best way of financing the projects'.

"In conclusion, the Bridging LWS calls for significant investment over an extended period to avoid catastrophic failures and help battle against climate change and population growth whilst maintaining a system which remains efficient, fit for purpose and discrete." - BLWS 2023-26.

The Environment, Housing and Infrastructure Scrutiny Panel has already launched a review of the Bridging Liquid Waste Strategy.

It will examine whether the solutions highlighted by the report are 'sustainable and suitable', or if there are other options that can be explored.

It will scrutinise what resilience the plan will deliver against events caused by climate change, such as like flooding.

In January, Grands Vaux residents had to be evacuated after heavy rainfall caused the reservoir to overflow, leading to sewage spill on popular beaches.

The panel says it will also consider the 'historic underfunding' of essential infrastructure and how government can take a long-term strategy to funding works.

The panel is gathering evidence (email scrutiny@gov.je) and will report back in August or September.