A BELEAGURED water company faced criticism at the weekend after residents in south Wales were told to boil their water, and a river was polluted.

Dwr Cymru told residents in Rhondda and the wider Rhondda Cynon Taf area to boil water after an issue was found with the chemical process used to treat drinking water.

A spokesperson for Dwr Cymru Welsh Water said: “A precautionary ‘boil water’ notice has been issued for customers in parts of Rhondda Cynon Taf.

“Following investigation by our operational teams, the issue affecting the chemical dosing process at the Maerdy treatment works has now been fixed, and water from the site is re-entering the network.

“Our teams are working to analyse water quality samples to ensure that the water in our network is of the highest quality.

“As a precaution, we ask that you continue to follow guidance and boil tap water before drinking, brushing teeth, preparing food or making ice until further notice.”

A river clean-up pressure group has found what it claims are very high levels of ammonia in the River Kenfig, near Port Talbot.

Local campaign group, Peace for Nature, said it found ammonia levels recorded at 50.6 mg.

“That is an exceptionally high level for a freshwater river – at the same time, dissolved oxygen has collapsed downstream,” the group said.

“High ammonia can be toxic to aquatic life, particularly where pH is elevated. Low dissolved oxygen means fish, invertebrates and other river life may not have enough oxygen to survive.

“A river with exceptionally high ammonia and critically depleted oxygen is not a river being restored. It is a river under severe wastewater-related stress.”

The group claimed aeration equipment may be creating localised oxygenation, but said the evidence shows that this effect is not being sustained downstream through the wider affected river system.

The group challenged Dwr Cymru to publish its monitoring data, saying the public has a right to know.

A Welsh Water spokesperson said: “We are currently working on a £13 million project to replace 4.5km of sewer main in the Kenfig and Port Talbot area to protect the local environment.

“Aeration equipment is in use to help improve the water quality of the river by introducing oxygen into the water to support aquatic life and reduce unpleasant odours.”