What is the requirement for water used in heating systems?

The requirement for water used in heating systems mandates the use of potable water. This is essential to ensure that the water that circulates through heating systems—especially those connected to potable water supplies—does not introduce any contaminants that could compromise drinking water safety. Heating systems can sometimes have interactions with potable water supplies, and if non-potable or contaminated water were used, it could lead to health risks for the occupants of the building.

Additionally, the use of potable water aligns with established codes and standards which aim to protect public health and safety. This requirement is particularly crucial in situations where the heating system might have the potential to create cross-connections with drinking water systems. Therefore, using potable water helps to maintain the integrity of the water supply and the overall safety of the building's residents.