Mass. Gen. Laws ch. 111 § 160C
As used in this section and sections one hundred and sixty B to one hundred and sixty G, inclusive, the following terms shall, unless the context clearly indicates otherwise, have the following meanings:--
"Department", the department of environmental protection.
"Home water treatment device", any product that (a) is designed to alter the chemical, electro-chemical, or physical properties or characteristics of drinking water, and (b) is used, sold, leased, or rented for use on residential real property primarily for personal, family, or household purposes.
"Purchaser", a person who purchases, leases or rents home water treatment devices.
"Seller", a person who sells, leases, rents or promotes home water treatment devices.
Mass. Gen. Laws ch. 111, § 160C