Board of Finance members on Tuesday unanimously approved a plan to bond $10 million to pay for what town officials say are critical repairs to the town’s three sewer plants and 17 pumping stations. Water Pollution Control Authority members have said the system is at a point where equipment is failing and more problems are expected. These would not only be costly but could result in the town violating its discharge permits and the state issuing fines and ordering the town to make repairs. Failures also could pose environmental threats to the Mystic River, Pawcatuck River and Stonington Harbor. Before the vote, finance board member Mike Fauerbach said that while the town cannot afford to have its sewer infrastructure fail, the $10 million in repairs are not the long-term solution to addressing the town’s three old sewer treatment plants. In 2010, town residents approved an $18.3 million plan to upgrade the three plants.