‘Madness’ to build houses without adequate sewage capacity

The lack of available sewage capacity to deal with the scale of proposed housebuilding in the Chichester district has been underlined by campaigners.

Thornham wastewater treatment works (Photo from Google Maps Street View)
Thornham wastewater treatment works (Photo from Google Maps Street View)

Last month, Chichester District Council’s leader and chief executive agreed to write to OFWAT to raise concerns about Southern Water’s ability to deal with the area’s waste water.

Councillors heard there are already capacity issues at seven of the ten wastewater treatment works, with the strain only becoming worse as thousands of new homes are built.

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In response Southern Water said it has a five-year plan to tackle the impacts of population growth and climate change with billions due to be spent across its network to improve and maintain assets.

The utility company explained how it regularly meets CDC and the Environment Agency to discuss where investment needs to be made.

Save Our Harbour Villages (SOHV) says it has spoken to Southern Water’s engagement and technical team about water treatment capacity and while there is some available it is in the wrong places.

Based on the revised housing allocations, SOHV has identified a shortfall in water treatment in both Pagham and Loxwood and a much more serious issue at Thornham, where calculations show capacity will likely run out by 2024.

All the villages for five miles along the A259 west from Chidham to Emsworth, including Westbourne, have their sewage fed into Thornham treatment on Thorney Island.

This would not only have to cope with new homes in the Chichester district, but also those built by Havant in Emsworth and the surrounding area.

Jane Towers, Chidham and Hambrook parish councillor, said: “At some point Southern Water will simply have to refuse permission for further connections to its sewer network. Given their data confirms Thornham sewage treatment capacity will run out in a few years, it is madness to have CDC 15-year housing allocations of this magnitude in villages served by Thornham works.”

The cost of upgrading treatment works is in the millions with money needing to be approved in advance by OFWAT.

Campaigners have argued that even if enough capacity is found at all the treatment works, this does not mean all the district’s pumping stations will be able to cope with thew thousands of extra homes or increasing winter storm flows due to climate change.

Andrew Kerry-Bedell, from SOHV, highlighted the sheer size of the network Southern Water was responsible for.

He said: “It’s no surprise they have no cash to upgrade any of Chichester’s treatment works until their next round of Ofwat funding in 2026. With the 10km Apuldram to Tangmere sewage pipeline also still not operational, options are severely limited to create treatment headroom for new housing until 2027 at the earliest.”