With all the beach closings due to fecal matter in the water along the Costa Blanca?
It seems to me that this year is worse than other years...
This is not the UK...

We had a pretty big storm around here earlier in the week, this in part would have flooded some areas and pushed contaminated water to the beaches.
All I can see are three beaches up near Denia and then one down near La Zenia, from my search of the area's local news.
We have nothing here from Calpe down past Alicante as it would have been in my local news feed.
So, four out of about 170, seems rather over the top or just sensationalising a minor story.

Been swimming in the sea at El Campello (just north Alicante) today and all is perfect.

So, you took your own test kit with you?

You dont need one unless you want to do so (its your choice)
Round here if we want a beach day, you can check with the local town hall or when at the beach there are flags.
On the one occassion we were in Calpe and there had been a storm the black flag was out at the lifeguard station.
The told us that there had been soil washed down from the hillside and for safety reasons we could not swim.

The flags on the beach will be Green (OK) Yellow (rough but watch it) Red (no swimming) Black (water or beach issues) or in some places a white one with blue jellyfish (leave that to your imagination to work out).
If the beach has a blue flag as well (and the costa blanca has 71 this year) those are ones where the water quality has been tested over a long period and is shown to be clean...

Is that when most (smart) people refrain from swimming or are the chances of being stung relatively small?

That depends where you are, if the map is accurate...

Paywall unfortunately...

we had it in Calpe this summer.

Just an idle guess, perhaps the DANA overran the sewage system and took it all out to sea where nobody really noticed until beach season?

I don't get one, are you outside of Spain at the moment?

no paywall for me!

If I use chrome browser the link has paywall if I use Brave browser it doesn't. I often use Brave for that reason

Yes - back in a few days, will try again then!