Several types of water are used in a power or process plant, and it is necessary to under­stand the differences correctly.

• Raw water. Water received at the premises of the users regardless of any previous treatment. The sources may be a river, lake, well, mine water, and so on.

• Treated water. Water that has received treatment at the premises of the users.

• Softened water. Water whose hardness has been removed substantially.

• Condensate. Condensed steam returned from a power or process plant without mixing with any other water.

• Demineralized water. Water nearly freed from total ionizable dissolved solids by passing through ion exchange materials.

• Feed water. Water passing through the feed pumps or ejectors containing any mix­ture of the above-mentioned waters.

• Boiler water. Water in the boiler with steaming in progress.

• Makeup water. Water added to the system to compensate for losses.