A ban on the sale of PET single-serve water bottles in Concord can go into effect Jan. 1, according to the state attorney general’s office.

The amendment to the town’s bylaws was approved 403-364 at a town meeting in April, but had to undergo a review by the attorney general’s office prior to implementation. A similar ban was passed in 2010, but later overturned by the attorney general as being unenforceable.

The attorney general’s letter to the town said the office does not agree or disagree with the policy, but noted that it is consistent with state and federal law. It also said it does not foreclose later court challenges to the bylaw.

The ban states that PET non-sparkling unflavored drinking water in bottles of 1 liter or less cannot be sold in Concord beginning Jan. 1. The first violation will result in a warning, with a $25 fine for the next, and a $50 fine for each subsequent violation.

There also is a provision for an exemption to the ban that can be enacted during emergencies.