Winter needs a low-sodium diet. Breakthroughs, discoveries, and DIY tips sent every weekday. Every winter across most of the northern US, giant bags of salt materialize at grocery stores and home improvement retailers as residents and business owners prepare to combat icy sidewalks and slick driveways. But when it comes to salting walkways and parking lots, most people overdo it, which costs more than just cash; using too much salt can have surprisingly harmful effects on the local environment, water quality, and human health. When salt is applied to roads and sidewalks as a deicing agent, as snow melts, salt gets washed into streams, lakes, and wetlands.