Environment Agency investigation into sewage treatment plant at Clehonger. Water company admits exceeding permitted levels of ammonia 7 times in a year.
The Environment Agency has successfully prosecuted Welsh Water for breaking conditions of an environmental permit at a Herefordshire sewage treatment works 7 times in a 5 month period.
At Kidderminster Magistrates Court on 11 July 2025, Welsh Water was fined £24,000 for exceeding permitted levels of sewage effluent from the Clehonger Sewage Treatment Works near Hereford. The company was also ordered to pay costs of £11,835.86 and a surcharge of £181.
Sewage treatment works treat raw sewage to produce an effluent which is discharged without damaging the local watercourse. At Clehonger, the water is discharged into the Cage Brook which is a tributary of the River Wye.
The court was told that officers from the Environment Agency were alerted to an issue following routine sampling results in November 2020.
The environmental permit states that Welsh Water must not discharge effluent containing more than 18 milligrams/litre of ammonia on more than 2 occasions in a 12-month period.
Results showed that in a 5 month period from 23 November 2020 to 17 April 2021 the limit had been exceeded 7 times ranging from 18.2 mg/l to 26.2 mg/l.
Officials from Welsh Water told the Environment Agency that the company was aware of additional loading coming into the site from a new development.
In mitigation, Welsh Water said that it had spent a significant amount of money to improve the infrastructure at the site. Adding, that since this incident there had been no further issues or breaches of permit condition.
Adam Shipp, a Senior Environment Officer at the Environment Agency who led the investigation, said:
Incidents like this are preventable and are completely unacceptable, particularly at a time when the need to protect the water environment for wildlife and people has never been greater.
Water companies are aware that their activities have the potential for serious environmental impacts, and they know that we will take action when they cause pollution.
The Environment Agency does and will continue to hold water companies to account when their performance falls below acceptable standards.
The Charge
Failing to comply with, or contravening, an environmental permit condition, contrary to Regulation 38(2) of the Environmental Permitting (England and Wales) Regulations 2016.
The particulars of the offence are as follows:
Dwr Cymru Cyfyngedig (trading as Welsh Water), Company Number 02366777, between the 23 November 2020 and the 17 April 2021, at the Clehonger Sewage Treatment Works, Herefordshire, failed to comply with, or contravened, an environmental permit condition, namely Condition 3.1.2 and Schedule 3 to Discharge Consent AH1000401, by exceeding the permitted level of 18 milligrams per litre of ammonia in the discharge from the said works to the Cage Brook, on seven occasions within the said period.
