Any water board or board of water commissioners of a city, town or water district and any executive officer or agent of any such board or of a public institution or water company furnishing water for domestic purposes, and any police officer employed by such a water board, board of water commissioners, public institution or water company, may enter any premises except dwelling houses within the water shed of the source of water supply of such city, town, district, institution or company to ascertain whether the provisions of this chapter relative to water supply and the rules and regulations adopted under section one hundred and sixty are being obeyed.
Mass. Gen. Laws ch. 111, § 173B