Mass. Gen. Laws ch. 21G § 13
For the purpose of determining compliance with this chapter or any regulations adopted thereunder, the duly authorized agents and employees of the department may at all reasonable times enter and examine any property, facility, operation or activity involving the withdrawal of water. The owner, operator or other person in charge of the property, facility, operation or activity, upon presentation of proper identification and purpose for inspection by the agents or employees of the department, shall give such agents and employees free and unrestricted entry and access. Such agents and employees are authorized to make such inspection, conduct such tests, reviews, studies, monitoring or sampling or examine books, papers and records pertinent to any matter relevant to the administration or enforcement of this chapter as it deems necessary.
Notwithstanding the provisions of any law to the contrary, any information, record, or particular part thereof, obtained by the department pursuant to the provisions of this chapter, shall, upon request, be kept confidential and not be considered to be a public record when it is deemed by the department that such information, record or report relates to secret processes, methods of manufacture or production, or that such information, record or report, if made public, would divulge a trade secret.
Mass. Gen. Laws ch. 21G, § 13