Concerns raised about Bay water quality

Ted Peskett, local democracy reporter

Poor water quality at Cardiff Bay is harming the ability for it to be used by members of the public and businesses, according to a city councillor.

Leader of the Conservative group at Cardiff Council, Cllr John Lancaster, raised his concerns about the Bay at a council environmental scrutiny committee meeting on Thursday, September 11.

His comments came moments after Cardiff Council cabinet member, Cllr Jennifer Burke, gave a statement about water quality monitoring in the fresh water lake, which is fed by the River Ely and River Taff.

Sewage discharges 

Cardiff Bay has been affected by sewage discharge from both rivers for some time and earlier this year it was revealed Aqua Park would be leaving it due to poor water quality.

Cllr John Lancaster said: “Clearly we have a responsibility to the people who live around the Bay, the people who use it, businesses that want to be there, so surely there has to be some sort of pressure from yourselves [council officers] to work with the likes of NRW [Natural Resources Wales] and Welsh Water to address it.”

The Cardiff Harbour Authority (CHA) publishes a daily water quality monitoring report on its website.

On the day of the meeting, Cllr Lancaster said he noticed four out of the six stations where monitoring takes place recorded a ‘fail’ for water quality.

“It’s not really good enough is it?” said Cllr Lancaster.

“There’s a real danger that poor quality is harming the ability of the Bay to be used by the citizens of Cardiff and businesses.

“Surely there should be some sort of attempt to address that and not just say, ‘well it’s coming from up stream… it’s out of our hands’.”

‘Fail’

Data published on the CHA’s website for Monday, September 15 showed all six monitoring stations recorded a ‘fail’ for water quality.

Monitoring at Cardiff Bay has been taking place since it was impounded by the creation of the barrage in 2000.

A report by the council states the CHA sampled for viruses for many years, but stopped in agreement with Public Health Wales because none were recorded.

Cllr Burke said in her statement that in the summer of 2024 following a series of illnesses, an incident management team chaired by Public Health Wales identified Norovirus as the cause.

The council report goes on to state: “The current monitoring programme looks for indicators of sewage contamination, therefore it is presumed that the source of Norovirus in the environment would be sewage related.

“It would be expected that there is some protection afforded by the current monitoring regime in respect to viruses.”

Norovirus testing

Earlier this year, a research programme was initiated with Bangor University to look at testing for Norovirus in Cardiff Bay.

In response to Cllr Lancaster’s comments, Cllr burke said: “I don’t think it’s fair to say that we’re just throwing our hands up and saying ‘we’re not doing anything’.

“Cardiff Council are working in partnership and pushing back on Welsh Water and Natural Resources Wales.

“We’re doing what we can with what legislation exists and obviously there’s part of this that sits with Welsh Government and the leaders that they have available.

“There’s only so much we can do and we are at the end of the waterway so whatever we’re doing locally is making an impact, but we can’t combat what’s happening further up the watercourse.”

Vale of Glamorgan Council revealed in March 2025 that Aqua Park would be leaving Cardiff Bay due to water quality issues.

The water-based inflatable assault course first opened on Cardiff Bay in 2022 and welcomed hundreds of visitors each summer.

It moved to Cosmeston Lakes near Penarth on a trial basis this year.

Failed tests

In March, a spokesperson for the CHA said: “Recent summers have been very wet and this increased rainfall, and the higher river flows that results in, have increased the number of failed tests.

“This in turn has impacted on the very limited number of activities allowed in the Bay which involve full immersion in the water.

“Cardiff Harbour Authority has no control over the quality of the water that flows into the Bay and as has been well-publicised recently, water quality is an issue in rivers, lakes and other fresh water bodies across the UK.”