But certainly the water is filtered before reaching homes, considering it rests a long time in a open reservoir. So you could remove the dead algae. Still, they certainly have a "better dead" approach, wanting the reservoir to be a dead pool instead of a living ecosystem where they'd have to monitor what is growing and how dangerous it might be.

It's interesting to compare different systems. Here's one for a small part of the UK. Our tap water (from thefaucet) is vety high quality.

http://www.thameswater.co.uk/cycles/accessible/water_treatme...

The last stage of the process is to add chlorine to the water.