What do you do when your water or sewer bill seems high? Most folks assume they have a leak somewhere, and call a plumber.That’s not so easy on Block Island these days.The Water and Sewer Commissions met for their monthly meeting on Monday, and had an interesting case before them. A longtime residential customer had seen the bill more than triple during the months of April to August this year, and has had a very difficult timeresolving the issue.When the bill jumped from the average of $110 to $182 in April, the customer called in the last remaining local plumber, who founda leak in the basement. It was a “pinhole” leak caused by copper sulfate in the old pipes.The plumber was unable to work on the leak, however, as he was overwhelmed with other projects. He referred the customers to a local steamfitter’s helper, who was unable to patch the pipe. The owners eventually found an off-island plumber who was able to fix the leak by mid- May.But when the bill was $494 in May, the customer called the water company, and Water Superintendent John Breunig came to take a look. He found a toilet and shower leaking