Yes, contrary to the other comments, the public water supply in Merrimack is safe to drink. Like you, I also called the water quality director and they kindly gave me a run down of all the upgrades that have been done (the final upgrade went live in October 2022 IIRC).

The new systems are also under the updated EPA thresholds, so Merrimack happens to be ahead of the curve in that regard.

Whether people ‘believe’ it’s safe is a separate question. I encourage anyone to call in or personally visit the town water facilities to receive education on the subject.