Why is it advised to boil water after a water main break?
Why is it advised to boil water after a water main break?
Because you get crap from outside the mains, such as dirt and and muck.
It also usually leads to a loss in system water pressure which could encourage growth of coliforms and other nasty little devils.
Not to mention the plastic and metal shavings and any chemicals used to seal the line. Get's really diluted in some places, others it might hit 30 homes and if you think cigarettes have some nasty stuff in em, that's nothing.
Because if it broke up it could let contaminants into your, I assume, otherwise healthy and cleaned water supply. While it might not necessarily get rid of some chemicals, it should at least kill any bacteria and possible parasites that could try to find their way into it. Yuck.
Because the integrity of the water has been compromised. They can't be sure what it could be contaminated with so its best just to be safe.