A boil water advisory is required any time pressure drops below 30 psi as per the EPA. Any state requirements supersede that as long as they are <30. My state, for instance, puts their minimum psi at 20.

99% of the time, when we have a main break, everything comes back fine and safe, but we are required to issue the boil water notice.

It takes 2-3 days to get the bact results back, depending on how busy the lab we use is. But in most cases, it’s completely fine.

Edit: I actually had it backwards. The EPA minimum is 20 psi. My states is 30 psi.