Lake Martin home sales have been great, but what is the magic statistic that lets us know if home prices are on the rise? John Coley is a senior member of the ACRE Leadership Council and fulltime real estate agent specializing in waterfront property on Lake Martin, Alabama. Lake Martin home sales have been great, but what is the magic statistic that lets us know if home prices are on the rise? Is there a magic statistic that lets us know that Lake Martin waterfront home prices are on the rise? I decided to look at a months of inventory, which I think can give us a better inclination if prices will be rising.