Section 15. Any city or town or any water company, public agency or authority of the commonwealth or its political subdivisions which is the operator of a public water system may petition the department for a declaration of a state of water emergency pursuant to this section. The department may require such city, town or operator to submit for review and approval by the department, a plan designed to bring about an expeditious end to the state of water emergency. Such plan may include provisions for taking actions authorized in section sixteen and provisions for restraining the use of water on public or private premises by shutting off the water at the meter or at the curb cock or by other means, and the department may require any further provisions it deems appropriate and feasible, including, but not limited to:

(1) an approved water resources management plan;

(2) a leak detection program;

(3) a program for auditing water use;

(4) a program for overall system rehabilitation;

(5) conservation programs for public and private buildings;

(6) bans or restrictions on certain water uses;

(7) a moratorium on the issuance of building permits;

(8) a plan for establishing priority for distribution of water among competing uses; and

(9) drought management or contingency plans.

Upon receiving a petition pursuant to this section, the department may declare a state of water emergency if it finds that there exists or impends a water supply shortage of a dimension which endangers the public health, safety or welfare. The department shall limit the applicability of any state of water emergency to the city or town submitting a petition pursuant to this section or the geographical area served by the public water system operator submitting a petition pursuant to this section. The department may amend the declaration or terminate the state of water emergency upon a finding that the public health, safety or welfare is no longer endangered by a water supply shortage in part or all of the area to which the emergency had been made applicable. The state of water emergency shall be in effect for no more than six months in the aggregate in any twelve month period unless the department determines that a longer state of emergency is required to protect the public health, safety or welfare.