Madison has a Winterization Ordinance that requires design, approval and installation of an engineered and fully code-compliant septic system, suitable for the finished house before a building permit is issued for conversion from seasonal to year-round use.

Occasionally a design cannot be approved without favorable results from ground water monitoring, which can only be done in the spring, during the period of highest ground water. Once a Winterization Permit is issued, conversion must be completed within 2 years. Because of size and soil conditions, not all properties are suitable for winterization.

Prior to enactment of the Winterization Ordinance, some seasonal properties had winterization approval, based on existing septic plans that could be installed in the future. These approvals remain in effect. We would expect the septic systems to be upgraded at least to the level of the existing plan at the time of winterization with the proviso that distances to groundwater and ledge will meet current Public Health Code. Previously winterized houses that have uninstalled septic system plans may keep their old out-of-date systems in place as long as they pose no health risk.