Is there some sort of legalese question you can ask to learn if the body of water you're about to enter is classified as a lake? Like: "is this a pool?". Sounds like a pretty big hole in the safety laws!
"Clean" is definitely not a word I'd use to describe this finding:
“Although the N. fowleri was not detected in the Surf Resort, Lazy River, or the Royal Flush, the presence of fecal indicator organisms, high turbidity, low free chlorine levels, and other amoeba that occur along with N. fowleri indicate conditions favorable for N. fowleri growth”
They're being charitable in their interpretation of the CDC's findings, to say the least.
What the article misses is the long tradition of river surfing all over the world. Championed at Munich Eisbach since the late 70ies, and then all over the world since the 90ies, esp. in Canada, Austria, Germany, USA and Switzerland. There's no need for an expensive and commercial pool with pumps if you just need to throw some big rocks into a river, or use a canal. It's also helping to save bridge piers, which otherwise need to repaired every 10 years.
In Montreal or Munich there are usually 200 surfers a day, surfing for free. With incredible tricks, previously only seen on a skateboard.
The wave pool there is classified as a 'lake' so normal rules for chlorination and filtration don't apply.
[0]: https://www.nj.com/atlantic/index.ssf/2018/10/brain-eating_a...