Freezing is very unlikely even if the home is unoccupied. Although located outside, the grinder pump and associated pressure piping would be fully enclosed at the bottom of a buried thick plastic holding tank, below the “frost line” for this part of the country. Nonetheless, we have and will continue to explore the freezing concern with major grinder pump system manufacturers and directly with cold-weather communities where such systems have been operating. To date, we have learned that freezing has not been a problem.