If it was clear you wouldn't be able to see it...right?:rolleyes:
By the way...if the water was so clean then faucet filters and bottled waters wouldn't be huge items around here. Just a reality check for you.

Faucet filters and bottled water is a matter of taste, not that the water coming out of your faucet is going to make you ill.
I wouldn`t want to drink straight river or lake water, but city water in Japan is safe and clean. But they filter and clean it (just like pretty much everywhere else with a proper water system) so it isn`t necessarily the tastiest water ever.

Nyororin is right. I filter my drinking water not because the tap water is dirty, but to remove some of the chlorine taste from the chemicals used to make the water clean. Same in my home country, where it is also safe to drink the water but city water supplies don't always taste the best.

Funny, there's a Jackie Chan drama called Shinjuku Incident. One of the movie's characters from China said the same thing about Japan.. :)