Treated wastewater can also be used for industrial purposes if suitable industries are not far from the treatment plant. Industry’s requirement for water quality ranges widely, from very pure water for boilers of electricity generation to lower water quality for cooling towers. Treated wastewater can fulfil the lower range of this requirement, e.g. water for cooling towers. After chlorination, Secondary-treated wastewater may be adequate for this purpose.

'Sewer mining' is the term given to the withdrawal of wastewater from a sewer for reuse near to the point of withdrawal. This provides an opportunity for reuse without having to pipe treated wastewater from the centralized treatment plant. Wastewater needs to be treated to the standard required for the reuse and may duplicate the function of the centralized treatment plant.

(UNEP 2000)