| #D001 | | source of water for reuse purposes | any alternative water source that can help offset the demand for traditional freshwater supplies. | high |
| #D002 | | Treated municipal wastewater | Treated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. | high |
| #D003 | | Onsite collected waters | Water sources generated within or surrounding a building, residence, or district. Other terms referring to this source of water include greywater, blackwater, air conditioning condensate, and foundation water. Rainwater collected onsite is a unique source water. | high |
| #D004 | | Industry process water | Water produced during industrial and manufacturing processes. Other terms referring to this source of water include air handling condensate, boiler, cooling or wash water, and water generated during oil and natural gas extraction. | high |
| #D005 | | Stormwater | Precipitation that is collected from land or impervious surfaces at a district or regional scale (e.g., using a municipal storm drain) for the purpose of beneficial reuse. Precipitation collection at the building scale is classified separately under 'rainwater collected onsite.’ | high |
| #D006 | | Rainwater collected onsite | Precipitation that is collected at a building scale for the purpose of beneficial reuse within or surrounding the building. Precipitation collected at the district or regional scale is classified separately under 'stormwater.' | high |
| #D007 | | reuse application | the recycling of an alternative source of water that is adequately treated for its intended use. | high |
| #D008 | | Potable water reuse | The use of highly treated recycled water for drinking water purposes. Includes the introduction of recycled water into an environmental buffer, such as groundwater aquifer or surface reservoir being withdrawn for potable purposes (indirect potable reuse), and the introduction of recycled water into a drinking water treatment facility or directly into a potable water distribution system (direct potable reuse). | high |
| #D009 | | Onsite non-potable water reuse | Water from onsite sources collected, treated, and used for non-potable purposes at the single-building or district scale. Excludes the use of recycled water from a centralized treatment and distribution system for landscaping or commercial uses (refer to “Water reuse for landscaping” and “Centralized non-potable reuse”). | high |
| #D010 | | Centralized non-potable reuse | The use of recycled water for centralized non-potable reuse where the water does not derive from the same site where it is to be reused. Can include, but is not limited to, toilet flushing, dust control, soil compaction, fire protection, commercial laundries, vehicle washing, street cleaning, snowmaking, and other similar uses. Excludes on-site non-potable water reuse and the use of recycled water for agriculture or landscaping. | high |
| #D011 | | Water reuse for agriculture | The use of recycled water to land to assist in the production of both commercially and non-commercially processed food crops consumed by humans or livestock and non-food crops. Includes pasture for milking and non-milking animals, fodder, fiber, and seed crops, vineyards, orchards, ornamental nursery stock, Christmas trees, and silviculture. Excludes consumption by livestock, onsite non-potable reuse, and landscaping. | high |
| #D012 | | Water reuse for landscaping | The use of recycled water on land to assist in the irrigation of vegetation in residential and non-residential areas. Includes impoundments to store water for irrigation , ornamental vegetation, parks, school yards, sporting facilities (including golf courses), private gardens, roadsides and greenbelts, and cemeteries. Excludes irrigation of areas used for agriculture, commercial reuse applications, or any centralized onsite non-potable reuse. | high |
| #D013 | | Water reuse for consumption by livestock | The use of recycled water for livestock drinking water supplies. Excludes physical application of reclaimed water to pasture for milking and non-milking animals, forage crops used as animal feed, and land used for livestock grazing. | high |
| #D014 | | Water reuse for environmental restoration | The use of recycled water to create, sustain, or augment water bodies including wetlands, aquatic habitats, or stream flow. Includes groundwater or aquifer recharge for protection from saltwater intrusion , stream flow augmentation and wildlife habitat, and source water protection. | high |
| #D015 | | Water reuse for impoundments | The use of recycled water in an impoundment (body of water within an enclosure). This includes both unrestricted (use of reclaimed water in an impoundment in which no limitations are imposed on body-contact water recreation activities) and restricted (use of reclaimed water in an impoundment where body contact is restricted). Includes recreational impoundments, aesthetic impoundments, and ornamental impoundments with and without public access. Excludes landscaping impoundments and storage of recycled water intended for other specific reuse applications (e.g., for agricultural irrigation). | high |
| #D016 | | impoundment | body of water within an enclosure | medium |
| #D017 | | Water reuse for industry | The use of recycled water for industrial applications, often created at the industrial facility. This includes recycled water generated through onsite processes such as boiler water, cooling water, manufacturing water, and oil and gas production, as well as recycled water generated offsite and imported elsewhere for industrial reuse applications. | high |
| #D018 | | REUSExplorer | Regulations and End-Use Specifications Explorer | high |
| #D019 | | indirect potable reuse | the introduction of recycled water into an environmental buffer, such as groundwater aquifer or surface reservoir being withdrawn for potable purposes | high |
| #D020 | | direct potable reuse | the introduction of recycled water into a drinking water treatment facility or directly into a potable water distribution system | high |
| #D021 | | unrestricted | use of reclaimed water in an impoundment in which no limitations are imposed on body-contact water recreation activities | high |
| #D022 | | restricted | use of reclaimed water in an impoundment where body contact is restricted | high |