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Upated: 22 May 2026

St Johns

We are progressing plans to replace the existing wastewater treatment works at St John’s, located alongside the Heritage Trail off Station Road.

The current facility, built in the 1970s, is approaching the end of its operational life and is no longer capable of meeting modern standards or future demand.

This proposed upgrade will provide a modern, reliable treatment works to:

  • Protect the local environment and nearby watercourses
  • Improve performance and resilience of the network
  • Support future growth in the local community
  • Meet current and future regulatory requirements

Why this work is needed

The existing works was designed for a different time, with lower population demand and older treatment standards.

Investment now will ensure:

  • Continued compliance with environmental standards
  • Improved treatment performance
  • Reduced risk of system failures or service disruption
  • A facility that meets the Island’s long-term needs

Current operations and monitoring

We are aware of recent public concern relating to wastewater discharges in the area.

For the majority of the year the current works operates within its design constraints with flows and discharges routinely monitored in line with regulatory requirements. At times of heavy rainfall, the system can experience increased volumes, which is a known limitation of older infrastructure designed to manage both wastewater and surface water. The existing works has also historically struggled during times of very dry weather and increased loading, such as during the TT festival. 

Short term fixes such as tankering flows and chemical dosing are being used to mitigate these issues as far as is reasonably practicable.

While these situations are managed in accordance with existing consents, they reinforce the need to invest in a modern facility that provides improved treatment performance, resilience, and capacity for the future.

What we are proposing

The scheme will replace the existing facility with modern Integrated Rotating Biological Contactors (IRBCs) — a proven and efficient form of wastewater treatment.

Similar systems are installed at fourteen sites across the Island, with the most recent example having been delivered at Crosby.

The upgraded works will include:

  • New treatment units (IRBC technology)
  • Pumping station and improved flow management
  • Modern screening equipment
  • Storm storage capacity
  • Odour control systems
  • Improved site access and landscaping

These improvements are designed to deliver a more reliable, efficient and environmentally compliant facility.

Access and construction impacts

We will aim to minimise disruption during construction.

  • No full road closures are currently anticipated
  • The Heritage Trail will remain open, with a temporary footpath maintained
  • Construction traffic will use existing access routes, including parts of the Trail
  • Short-duration closures of the Heritage Trail may be required at key stages for safety

Any temporary restrictions will be communicated in advance.

Programme

The current anticipated programme is:

  • Planning submission: summer 2026
  • Construction start: early 2028 (subject to approval)
  • Construction duration: approximately 2.5 years

Engagement and updates

We are committed to keeping the community informed as the project develops.

We have already held constructive discussions with local representatives and will continue to engage with residents and stakeholders throughout the process.

Further updates will be shared here as more information becomes available.