All acts and parts of acts passed prior to March sixteenth, one thousand nine hundred and sixteen, granting to the state water supply commission or its successors in authority the powers in this chapter granted to the boards of district water supply commissions, when created as herein provided, are hereby repealed, but nothing in this repealer contained shall be held to affect the powers of any municipality, by condemnation or otherwise, to develop, acquire, operate, enlarge or improve its water supply existing on March sixteenth, one thousand nine hundred and sixteen, from its then source of supply, nor the performance of any then existing contract relating to its water supply.