The ratio of 1 in 30 is a magic number for contractors who build homes in Massachusetts. In New Hampshire the number is 1 in 60. Vermont's number is 1 in 60, or 1 in 120 for a "mound" system. Maine doesn't have a magic number. Confused? Welcome to perc-rate lotto. Percolation rates, the time it takes one inch of water to drain from a hole dug near a proposed septic system, must be determined before building permits are issued in most rural communities in the U.S. If your rate does not meet the legal minimum, then you can't build on the site. Some states and towns have more rational regulations than others, but every state has some
