Manx Utilities says its waste treatment plant for Peel may not be finished until 2028 - but it'll start cleaning sewage next year.
Chair John Wannenburgh was replying to a question for written reply from Glenfaba and Peel MHK Kate Lord-Brennan about the timetable for the work.
In his response, Mr Wannenburgh said primary treatment screening should be ready next summer, while biological treatment will begin the following year.
He added earth-moving work, due to take place over the next six months, are most at risk of running behind.
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