Chichester MP calls for phosphate limit at Lavant wastewater works

The MP said the call followed what she described as ‘alarming’ data collected by citizen scientists working with the Western Sussex Rivers Trust.

She said: “I’m calling on the Environment Agency to introduce a phosphate permit at the wastewater treatment works in Lavant, so Southern Water would have clear enforceable targets for phosphate reduction.”

The Environment Agency confirmed that the environmental permit for Lavant Wastewater Treatment Plant does not currently include a phosphate limit.

An Environment Agency spokesperson said: "We know how much the River Lavant matters to people living nearby, and we want to protect and improve it for the future.

"Phosphate pollution in the river can come from several sources, including wastewater treatment works, storm overflows, farming, and runoff from towns and roads.

"We've told Southern Water to investigate how much their wastewater discharges are contributing to phosphate pollution.

Once we've seen the results, we'll decide whether further action is needed, such as changing their permits or setting new limits on phosphate levels."

The MP also raised concerns related to storm overflow activity at the site.

Figures published by the Environment Agency show that in 2025, Southern Water’s Lavant treatment works discharged partially treated or untreated sewage for 3,982 hours, the equivalent of almost half the year.

A spokesperson for Southern Water said: "We're committed to improving the health of the River Lavant and have already invested significantly at Lavant Wastewater Treatment Works, including the creation of a wetland and a new storm tank.

"We will also be introducing further improvements to reduce nitrogen and ammonia levels in treated wastewater, helping to improve water quality in the river.

"In addition, we're sealing sections of the sewer network across the Lavant Valley to reduce groundwater entering the system, improving network resilience and helping to reduce the risk of storm overflows."

Following her call the Chichester MP also thanked citizen scientists across the district who help monitor the rivers.

She said: “I’m so grateful to the citizen scientists across the Chichester constituency who are monitoring the health of not just the Lavant but also the Ems, which has its own unique challenges after years of over-abstraction, as well as the Bosham Stream and the Ham Brook.

"The health of these rivers contributes to the overall health of our harbours, and we are rich in knowledge thanks to their efforts.”