Section 20B. No regional veterans' district, regional water district or regional sewerage district authorized by law to assess costs, charges or fees upon cities and towns may increase the total of such costs, charges or fees by more than the sum of: (1) two and one-half per cent of the total of such costs, charges or fees over the preceding fiscal year; and (2) any increases in costs, charges or fees for services customarily provided locally or for services subscribed to at local option; provided, however, that such districts may exceed this limitation in the manner provided by this section.

In all but two-member districts, any increase above the limitation set out above shall be approved by a two-thirds vote of the district's governing body and, thereafter, shall require the approval of two-thirds of the local appropriating authorities of the several municipalities.

In a two-member district, any increase above the limitation set out above shall be approved by a two-thirds vote of the district's governing body and, thereafter, shall require the approval of the local appropriating authorities of both member municipalities. In the event both municipalities fail to approve in the manner required, the district's governing body shall convene a special district-wide meeting open to all registered voters in both municipalities at which the increase shall be considered. At such special meeting, the increase shall require the approval of a majority of those present and voting, by a counted vote.

In the event that the increase does not receive the necessary approvals as required by this section, it shall be recommitted to the district's governing body which shall have thirty days to amend and to resubmit said increase for approval in accordance with this section.