Johnston Supply, Inc. is an independent wholesale distributor that serves the residential and light commercial professional contractor. If you are not currently a customer and would like more information about our company, please contact one of our branch locations near you. Johnston Supply, Inc. is a privately held corporation founded in 1932 in Marion, Ohio. The Company has six Branch Locations serving the professional contractors in Northern Ohio, Southern Michigan and Northeastern Indiana. Our knowledgeable staff can assist you with your product selection, sizing and design for Plumbing, HVAC, Radiant Heat, Water Filtration, Water Well Pumps and Dewatering Applications.