Eight beaches across the Vale of Glamorgan have received their annual grades for bathing water quality.
Natural Resources Wales (NRW) said three beaches retained their 'excellent' grading - namely the Cold Knap in Barry, Col-huw Beach in Llantwit Major and Southerndown.
There were 'good' grades for both Jackson's Bay and Whitmore Bay along with Penarth beach.
But Watch House Bay (also known as Watchtower Bay) has been downgraded from 'sufficient' to ;'poor' - while Ogmore-by-Sea, where bathing status was secured three years ago, has again retained its 'poor' rating.
They were the only locations across Wales to record the lowest possible grade, following annual tests over the summer.
Vale of Glamorgan Council described the results for Watch House Bay and Ogmore-by-Sea as ''very disappointing'' and advised would-be swimmers to stay out of the water at both sites.
The beach is situated about a mile away from the Pen-y-Bont wastewater treatment works - and in May last year, swimmers were told not to go in the sea following what NRW called an "ongoing pollution event".
Restrictions were lifted a month later after a small leak had been traced to a groundwater pipe rather than the treatment works as originally suspected.
Watch House Bay, which also receieved its first grades in 2023, had been initially deemed to have 'poor' water quality but it receieved a 'sufficient' grading last year.
A spokesperson for Vale of Glamorgan Council told Bro Radio News: "The council is not responsible for maintaining water quality at beaches as it is a matter for Natural Resources Wales (NRW) and Dŵr Cymru."
"However, we do want everyone to enjoy these locations so the results for Watch House Bay and Ogmore are very disappointing."
"Unfortunately, this testing does not determine the reason for poor water quality. There are a number of natural factors and potential pollutants that could affect the situation, and we are keen to work with NRW and Dŵr Cymru to improve bathing water quality."
"Everyone wants to enjoy clean bathing water and we want that too. But, unfortunately, for the time being we must advise against bathing in the water at these locations."
"There are of course a number of other beaches in the Vale with excellent water quality that are ideal for bathing."
The Welsh Government said 98& of all bathing waters across Wales had met "stringent compliance standards" and the vast majority - 78 out of 112 designated sites - had achieved "excellent" status.
Deputy First Minister Huw Irranca-Davies said: "I'm particularly encouraged by a standout performance from one of our newly designated sites, Llanishen reservoir in Cardiff, which has achieved 'excellent' status in its first year– a remarkable achievement."
But despite a largely positive outlook, there was a warning that environmental factors can significantly affect water quality - such as the exceptionally wet September, right at the end of the bathing season.
Huw Irranca-Davies added: "As we continue to face the effects of climate change, maintaining and improving our bathing water standards requires sustained investment, innovation, and partnership working across all sectors."
"Last month, I outlined plans to fundamentally reform the way water is managed, regulated and delivered in Wales. This really is a golden opportunity to create a better system that puts people, the environment and future generations at its heart."
Mary Lewis, head of natural resource management at NRW, added: "Our wonderful beaches and bathing waters are an important part of Wales's identity and culture."
"They are home to rare and unique species, provide spaces to unwind and connect with others and help local economies to thrive."
"In the midst of climate and nature emergencies, maintaining the high standard of our bathing waters is an increasing challenge. But the results reflect the dedication of our teams, partners, environmental groups and communities who protect and care for our environment."
"As Wales's environmental regulator, we are working hard to reduce pollution at its source, enforce against those who harm our waters and collaborate with partners on solutions."
"We continue to drive action and investment from all sectors to secure sustained, long-term improvements for nature and people, and the future of Welsh waters."

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