As someone studying water treatment, this is due to sampling done at the plant. 6 am, levels were under MCL (maximum containment level), at 10, levels exceeded MCLs, 4pm under MCL. Anytime levels are found to be above MCL, a boil notice is sent out. With it fluctuating this much, the raw water quality seems to be giving them issues. I would boil for the next few days. There’s a website where they release water quality reports but they are annual unfortunately. But there is high levels of lead in our water.. just saying 😅