The use of wastewater in agricultural irrigation has the potential for positive and negative environmental impacts.With careful planning and management, the use of wastewater can be beneficial to the environment. Constructedwetlands are usedworldwideforwastewater treatment, and this study discussesthe resultsofthesewetlandsincold and moderateregions ofthe world.Results show a remarkable BOD5 removal efficiency (58.8-99.84% of the influent BOD5 concentration( , even though only 62% of these wetlands were constructed following the U.S. EPA guidelines. The constructed wetlands can help remove TSS up to a level that is compatible with the quality standards for most reuse application in irrigation of crops. These wetlands cannot provide a water reclamation solution from a microbiological quality perspective that can meet reuse quality standards for irrigation.In terms of acidity, the effluent from constructed wetlands in cold climate is appropriate for irrigation of all crops. As a result, for reusing constructed wetland effluent in irrigation, combined systems like WSP-CW system require complying with the standard effluent for reuse water