Wastewater reuse plays a key role in this vital cycle of water because it is able to reduce the wastewater spilled. Simultaneously, the supply of water for specific uses is increased. A new regulation (Royal Decree 1620/2007) came into force in Spain in December 2007 and regulates the basic conditions for the wastewater reuse and establishes the required criteria of quality to waters according to use. In the present paper, different kinds of tertiary treatments in reuse of wastewater are described. We focused on the applied tertiary treatments in most wastewater treatment plants of Gran Canaria Island. Particularly. we analysed Hoya del Pozo wastewater treatment plant due to its wide number of technologies and processes. Finally, we reviewed the quality criteria used in the regenerated waters. in agreement with the new regulations. (C) 2009 Elsevier B.V. All rights reserved.