Yes, that's one of the main reasons I settled in "Les Landes" (Hossegor) rather than the nearby Basque Country (Biarritz, Guetary), for the pristine water quality of Les Landes. Beaches in the Basque Country are nearly always closed for pollution after big rains.
I am a member of the Surfrider Foundations, which helps awareness on these subjects, but here we can thank a lot the EU, and the green parties at the EU parliament, which has been the main driving force to fight for water quality. The improvement in water quality has been nothing short of spectacular here, both in France and in Spain, as efforts have been made to modernize waste management, especially in Spain, build lots of water treatment plants...
You can now surf near the Bidassoa rivermouth (at the French/Spain border) in clean water, and it is quite incredible considering the situation 20 years ago. And 20 years ago, the Hossegor beaches were covered daily in Spanish trash (from the labels), whereas now storms only bring driftwood and very few man-made trash.
This shows the huge benefits of the European Union: it can better force strict laws, designed for the common good, upon local politicians who do not have the strength nor the money to resist industrial lobbies. Of course our local would-be corruptees and corrupters whine that the EU is "stealing their sovereignty", but here in Spain and France we are lucky that we do not have laws that make media unaccountable for lies, so the amount of public disinformation have not (yet?) reached the frightening efficiency levels of the UK & US. And our Trump/Boris, Marine Le Pen, thankfully lacks the pathological narcissism to fuel a power grab.
PS: The "Blue Flag" - a French program, started in 1985 - exist now in many countries, but alas is not only about water quality, but it is much better than the previous situation.
beachawards.ie/wp-content/uploads/2018/06/Blue-Flag-Beach-Criteria-Ireland-2018.pdf