As of 2015, a good location to buy Kohler toilet seat parts is through the Kohler manufacturer. Parts for numerous brands of Kohler toilets can be ordered through the company website.
Kohler also sells sinks, faucets and shower accessories for the bathroom and kitchen sinks and faucets are available as well. Parts can be ordered online or by phone.
Another good location that sells Kohler toilet seat parts is Home Depot. The home-improvement store carries a variety of parts and accessories. Prices and model parts vary by location.
Lowe's is an additional location for Kohler products. Lowe's stores can be found throughout the U.S.