SECTION 1. Chapter 18 of the General Laws is hereby amended by inserting after section 21 the following new section:--

SECTION 22.  The owner of a two family apartment building, when said owner occupies one of the apartments, may, with the willing consent of the tenant, install a water meter on his solar hot water tank and charge the tenant for hot water drawn from said solar tank.  Any such water meter must be installed so that it measures only the solar hot water used by the tenant.

Charges for solar hot water shall be at the current rate charged to the owner by the entity supplying the water.  It shall be the responsibility of the tenant to notify the owner of any problem in the hot water system, which might cause an increase in hot water used.  If the owner fails to repair the problem within five working days after notification, the tenant may contract to have the necessary repairs made at the expense of the owner.