As a pp has said, they’re holiday homes, you can’t live there permanently. (Although I used to know someone who did - not sure how she managed it.)
A friend lives close to this development. One of the lakes (I think they’re flooded gravel,pits) was very close to her house, so before the development, in summer they used to swim in it - no longer. 🤬. Water was very clean. I do remember seeing a snake swimming in it while I was once having a dip! Probably just a grass snake - I gather that they’re good swimmers.
The properties are popular with well-heeled Londoners, since not far to go for the weekend, with various sports inc. water-skiing, thrown in.