Real World Situation

[Nowhere Man 1966]

Here in Pittsburgh, I remember in 1988 when the Ashland oil tank collapsed and the oil went into the Monongahela and downward into the Ohio, almost all the communities had to restrict water use except mine. Most communities get their water directly from one of the three rivers but mine gets it from an underwater spring that is under the Ohio so we were the only one that had no water restrictions. I know in times of emergencies a few surrounding communities can now bum water off of us. We were like a small island surrounded by chaos.

Chuck

[irishboy]

1.) I think the key word in the whole situation is 'system'. Once the break occurred and the pressure was lost, who knows how far back up the pipeline any contaminants could have spread? Sure, once pressure has been restored, it's unlikely that you'd have anything new coming in, but if there was an issue during the 'down' period, it could take a while before anyone found it. So they have to treat the whole system as possibly contaminated.

2.) I did a quick google search using the terms "boiling water for purification" and lots of relevant data came up. One site (http://giardiaclub.com/water-purification.html) specifically addressed the boiling time, saying that the long times aren't neccessary, as long as you only count the time that the water is at a full, rolling boil. That, and that for higher elevations you need to add more time (1 extra minute for every 1,000 ft of elevation).

[Legbreaker]

When dealing with the public, the rule of thumb is "treat everyone like an idiot".
Although the water might only need say 30 seconds at a full boil to be safe, there are some people out there that begin counting the very moment the water is placed on the heat... Unfortunately for the gene pool, the authorities have to consider these unfortunates when issuing instructions.