There are a good number of private septic systems in Washtenaw County. Assessments show that nearly half of those systems have exceeded their expected lifespans and could fail in the near future. That would not only threaten the ecosystems of local waterways but also put public health in jeopardy. The Huron River Watershed Council is advocating that the private septic systems be replaced with centralized water treatment systems. WEMU's David Fair talked with the council’s Ric Lawson about what it would take to make that change.