Any public, academic, school and special library within a region will be eligible to participate as a member of a Regional Library System upon meeting certain requirements. These requirements are that the participating library shall:
(b) have an organized collection of information and material accessible for use by its designated clientele;
(c) have a fixed location;
(d) have established and posted hours of service;
(e) have an on site, paid librarian-in-charge who meets Massachusetts education and certification requirements in effect for that type of library. (For public schools, each secondary school library member must be staffed by a full time certified library teacher, and each non-secondary school library member must be staffed by either a full or part time certified library teacher. For each non public school and each charter school, a Masters in Library Science degree shall be considered equivalent to a library teacher certification for purposes of meeting this requirement);
(f) have a written mission statement and service objectives, which the library reviews and evaluates annually;
(g) have an established funding base and an annual budget;
(h) be authorized to participate by its appropriate administrative authority;
(i) agree to the terms and conditions of the regional library system membership agreement as established by the Board of Library Commissioners. This agreement shall include certification by each member library that it meets the minimum eligibility requirements for participation, agrees to participate in interlibrary loan activities within the Commonwealth in accordance with the National Interlibrary Loan Code for the United States and agrees to provide data on the use of regional and statewide library materials and services.
All public libraries that are currently members of a Regional Public Library System are automatically members of the Regional Library System.
From Code of Massachusetts Regulations 605 CMR 7.02 "Regional Library Systems; Eligibility Requirements for Participation as a Member of a Regional Library System"