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Ice formation inside steel potable water storage tanks is a common occurrence in the northern US and throughout most of Canada during the winter. Depending on the average air temperature, the inlet water temperature and the amount of turn-over, ice formation can range from a thin skin on the top and northern walls of a water tank to a massive ice cap that weighs many tons.

While most people enjoy a little ice in their glass of water, thick ice in a water tank can spell disaster. Operations are compromised when ice build-up inside tanks can lock-up millions of gallons of storage, leaving utilities exposed and unable to respond in emergency situations. Infrastructure is damaged when a jagged plug of ice scrapes the sides of a water tank as the water level fluctuates. If internal hardware (such as ladders and cathodic protection) inside a tank becomes locked in the ice, the rise and fall of the ice cap can literally tear this hardware apart. Each spring, even modest damage to tank coatings may require partial or complete overhaul, costing tens of thousands of dollars. This damage is preventable.

Moving water is more difficult to freeze than still water. If the warm water (~35-42°F) which enters the bottom of tanks during fill cycles is circulated to the top layers in a consistent flow pattern, then freezing should be reduced or prevented.