The environmental group Sons of Neptune has said it is “confident” that upgrades in sewage quality will achieve “significant improvements” in Scarborough’s bathing water quality next year.

It follows a weekend of heavy rainfall with many members of the public taking to social media to raise concerns about apparent sewage discharges on the coast.

During significant rainfall “heavily diluted” storm water may be diverted into the sea to “prevent flooding to properties and roads”, according to Yorkshire Water.

Surfers Against Sewage, a marine conservation and campaigning charity, also issued sewage pollution alerts for Scarborough’s North and South bays which are classified as “excellent” and “poor” on the Environment Agency’s website, respectively.

Freddie Drabble, leader of the campaign group Sons of Neptune, said that increased monitoring and sampling of seawater was needed to improve bathing water in Scarborough’s South Bay.

He said: “A lot of work has been done and I think next year, sampling [of water quality] is the first and most important thing to check how we’re getting along month by month, so we know if improvements that have been made are working and are taking effect.”

Currently, the Environment Agency carries out weekly testing of bathing water in Scarborough between May and September, but Mr Drabble called for sampling funded by water companies to take place “irrespective of the bathing season”.

Sons of Neptune is a Scarborough-based environmental group that gained national awareness in the 1980s and 1990s as a result of its campaign to stop untreated sewage being discharged to the sea.

Mr Drabble said that past differences with Yorkshire Water had been set aside “many years ago to enable sharing of research including consultants’ reports” and added that he had “confidence that upgrades in effluent quality will achieve significant improvements in bathing water quality next year”.

Speaking to the Local Democracy Reporting Service, he conceded that enough had not been done by water companies to limit the level of sewage discharges and said he hoped the Environment Agency would be given greater powers to enforce compliance.

He added: “To avoid being placed again next year in the “poor” rating category under the four-year average rule, even before the start of the season, it is hoped that the Environment Agency might be willing, subject to satisfactory results of tests on the substantially upgraded effluent quality, to consider deferring a rating for the South Bay for the 2024 bathing season until the full year’s sampling results are available.”

In June, a cross-party group of councillors passed a motion expressing their “deep concern” over the South Bay’s water quality and called for “accurate measuring of the effluent from all sea outfall pipes” in the area.

Yorkshire Water was contacted for comment.