Built Like a Bock

Bock Water Heaters are proudly manufactured in our two Wisconsin facilities. We are a 100% employee owned company, meaning we are each personally committed to providing the highest level of product quality, customer and technical support. We utilize the thickest steel in the industry, up to 40% thicker than our competitors, protected with cobalt rich C-Glass, for the highest level resistance to corrosion. This allows Bock to provide you a five year warranty, one of the longest in the industry.

See for yourself what it means to have a product “Built Like a Bock.”



Oscar Bock, a young engineer/inventor, establishes Bock Water Heater in Madison Wisconsin, a manufacturer of oil fired water heaters and burners. Bock today remains the #1 selling oil fired water heater in North America.


The Early Years

Bock utilizes its expertise in oil to begin manufacturing gas fired water heaters. We have been a leader now in gas water heaters for over 70 years.


An Industry Changing Innovation

Bock launches the Turboflue Heat Exchanger, with steel fins engineered in a precise spiral design to create a revolutionary breakthrough in heat transfer efficiency. This design remains today a key reason for the exceptional level of heat efficiency provided by Bock heaters.


Acquisition of Tank Technology

Bock acquires Tank Technology in Princeton, Wisconsin to further control quality and supply of Bock water heaters.


Indirect Water Heaters

Bock begins manufacturing indirect water heaters under the SideKick™ brand name.


100% Employee Owned

Company becomes a 100% employee owned ESOP. Every employee, and only those working for the company, is an owner operator, helping to deliver the highest level of employee commitment to sales and service of our products.


ezFIT™ Gas Fired Atmospheric Water Heaters

Bock launches ezFIT™ gas fired atmospheric water heaters as an easy replacement for most competitive heaters.


OptiTHERM® High Efficiency Condensing Water Heaters

Bock launches OptiTHERM High Efficiency Condensing Water Heaters, with state of the art electronic controls, up to 99% thermal efficiency and 5 year warranty. Bock later builds upon the high level of success of this product with expansion to smaller BTU ranges.


OptiTHERM® Outdoor

Bock launches the first water heater for use in climate acceptable outdoor locations.


New ElectriTHERM™

Bock launches ElectriTHERM Heavy Duty Digital Electric Water Heaters with the same high level quality, warranty and support that have made all Bock Water Heaters the product of choice in any commercial application.


New Higher BTU OptiTHERM®

Bock launches new 600,000–900,000 BTU OptiTHERMs. Tank size 130 gallons, turndown ratio as low as 6:1, front venting, touchscreen controls, all the while still fitting through a 36" door. Exciting new commercial product.