Water Reuse Frequently Asked Questions
- Why should we reuse water?
- What is the difference between recycled water and reclaimed water?
- How can recycled/reclaimed water benefit us?
- How is water recycled/reclaimed?
- Is recycled/reclaimed water safe?
- How is recycled/reclaimed water different from raw water?
- Does recycled/reclaimed water need to be kept separate from other water?
- Who regulates water reuse?
Water reuse offers a climate independent water source that is dependable, locally-controlled, and generally beneficial to the environment. Water reuse allows communities to become less dependent on groundwater and surface water sources and can decrease the diversion of water from sensitive ecosystems. Additionally, water reuse may reduce the nutrient loads from wastewater discharges into waterways, thereby reducing and preventing pollution. This “new” water source may also be used to replenish overdrawn water sources and rejuvenate or reestablish those previously destroyed.
These terms are generally used interchangeably and which word is used depends on the region. Recycled or reclaimed water is water that is used more than one time before it passes back into the natural water cycle. Thus, water recycling is the reuse of treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, or replenishing a groundwater basin (referred to as groundwater recharge).
Recycled water can be used in numerous applications to satisfy most water demands, depending on the level of treatment. The water is treated to meet regulatory guidelines for the intended end use. Typical uses for recycled/reclaimed water include:
Surface irrigation of orchards and vineyards
Wetlands, wildlife habitat, stream augmentation
Industrial cooling processes
Landscape and golf course irrigation
Food crop irrigation
- Potable reuse (typically recharge of groundwater or surface water to augment drinking water supplies)
Water utilities use a variety of well-tested and reliable treatment processes to reycle/reclaim water. Utilities generally describe the various stages of treatment rather than the technologies utilized when referring to water quality, as there are multiple treatment techniques for achieving essentially the same result. Generally speaking, the four core stages of treatment are Primary Treatment, Secondary Treatment, Tertiary or Advanced Treatment, and Disinfection. The number of treatment steps will vary based on how the water will be used. Most recycled water, however, will undergo some form of disinfection.
Reclaimed water is highly engineered for safety and reliability so that the quality of reclaimed water is more predictable than many existing surface and groundwater sources. Reclaimed water is considered safe when appropriately used. Reclaimed water planned for use in recharging our aquifers or augmenting our surface water receives adequate and reliable treatment before mixing with naturally occurring water and undergoing natural restoration processes. Some of this water eventually becomes part of our drinking water supplies.
Through the natural water cycle, the earth has recycled and reused water for millions of years. Water utilities use technology to speed up these natural processes. The Colorado River and the Mississippi River are two common sources of raw water in the United States. Along these rivers, communities often discharge wastewater upstream from other communities that will later treat the water for drinking purposes. The water from these rivers has been reused, treated, and piped into the water supply a number of times before the last downstream user withdraws the water. Water that is perceived as raw water has often been used recently. The quality of the water is much more important than the source of the water. Water utilities employ the best technology and follow stringent guidelines to treat water to a quality commensurate with the intended use.
Nonpotable recycled water goes through a separate pipeline system to the customers. It is completely separate from the drinking water pipeline system. Periodic cross connection tests ensure that the nonpotable recycled water pipelines are not accidentally connected to the drinking water system. In addition, there is ongoing monitoring and testing of the nonpotable recycled water and drinking water systems to protect the public's health.
Several states consider reclaimed water viable as a water source alternative, and have developed regulations with specific water quality requirements and or treatment processes for a variety of reuse applications. In other states water reuse regulations have been developed with the primary intent of providing a disposal alternative to surface water discharge. A few states have no specific regulations or guidelines on water reclamation and reuse, although programs may still be permitted with approval on a case-by-case basis. In 2012, the U.S. Environmental Protection Agency released an updated technical document entitled Guidelines for Water Reuse, which was developed specifically for application in those states with no regulations for all or some type of reuse.