Irish Water, working with Leitrim County Council, is replacing about 130 metres of old water mains in Drumshanbo.
The pipes, on the Hilly Road in the town, were prone to frequent bursts and leakage and caused water supply disruptions for customers in the area.
The old cast iron water mains are being replaced with new plastic pipes.
Declan Cawley, of Irish Water, said the works will minimise disruptions in supply by reducing leakage and unplanned outages when bursts occur on the existing main.
The works are due to be completed by the end of July.
Farrans Construction Ltd is contracted to carry out the work on behalf of Irish Water.