There's no official truth, actually, there never is in these cases.
We have info, though:
http://radio.uchile.cl/2016/01/17/d...-del-agua-que-consume-la-region-metropolitana
So we have Alto Maipo with that contamination in the place where the event that you mention is triggered with a simple rain (remember, this originated on friday, not saturday).
The official statement of Aguas Andinas is that "high turbidity" cannot be fought with, so they have to cut the supply in 27 comunas of Santiago.
Which, to various organizations, seems weird, seeing that other years we've had the same ammout of rain and in similar conditions, and it hasn't happened.
http://www.infogate.cl/2016/04/16/a...ple-lluvia-basta-para-provocar-un-mega-corte/
But in any case, with nature beign disturbed, of course things would be different this year. The river would not behave normally.
And I'm going full ancient aliens with this shit, but it does drives me crazy:
Timing's a weird thing sometimes. Just a few weeks ago, there was some question beign made about the partnership of Aguas Andinas and the company behind Alto Maipo, precisely one of the points was that of the water supply. Of course, everything was green lighted
http://www.latercera.com/noticia/ne...convenio-entre-aguas-andinasy-aes-gener.shtml
And just thinking about Luksic beign behind CCU, Cachantun, and this causing a bottled water bonanza in supermarkets, makes me feel a little more biased into think that he just don't give a shit about all of this.
Of course, I could be wrong. But the corruption in this country is so high, specially with guys who practically owns the country like Andronico, makes me question all of this stuff.