The zoning bylaw may be adopted and from time to time changed by amendment, addition or repeal, but only in the manner hereinafter provided. Adoption or change of the zoning bylaw may be initiated by the board of selectmen, the board of appeals, by an individual owning land with respect to which a change is sought, by request of registered voters of Swansea pursuant of [to] MGL c. 39, § 10, by the planning board, or by the regional planning agency. The board of selectmen shall within 14 days of receipt of such zoning bylaw amendment submit it to the planning board for review and a public hearing, to be held within 65 days of transmittal by the selectmen.

No proposed zoning bylaw or amendment which has been unfavorably acted upon by the town meeting shall be considered by the town meeting within two years after the date of such unfavorable action unless the adoption of such proposed bylaw or amendment is recommended in the final report of the planning board.

After town meeting adoption, Swansea must submit any bylaw or amendment thereto to the attorney general for approval. A statement must also be sent which explains the bylaws or amendment, which statement may be accompanied by explanatory maps or plans.

Within 120 days after adoption of an ordinance, bylaw or amendment thereto, legal action may be taken regarding defects in the procedure of adoption. Within seven days after commencement of the action, a copy of the petition must be filed with the town clerk. Unless an ordinance or bylaw is found to be invalid through the above action, a claim of invalidity may not be made in any future legal proceedings.