All About Greywater Reuse

Water scarcity is a growing problem around the world. In the United States — particularly in arid states like California, Arizona, and Colorado — frequent droughts and shrinking water supplies are driving a rise in water prices and water restrictions. This is feeding demand for new solutions.

In the face of growing drought and water scarcity, reusing our greywater is one thing we can do to save more water, make the most of the water we already have, and create a sustainable water supply for future generations.

Unfortunately, many well-established conservation measures can carry a cost to personal lifestyle and comfort. Purchasing high-efficiency household appliances, planting drought-tolerant landscapes, or switching to a vegan diet will reduce our water consumption, but many people are reluctant to give up full showers and lush gardens.

We could increase our existing supply of water by digging new wells or constructing desalination plants. For most communities, however, this approach is prohibitively expensive. Furthermore, extracting even more of an already dwindling resource just makes the problem worse for future generations.

Additionally, water reuse doesn’t just save water; it saves money and energy as well. Using our water twice means we only pay for it once; that second use is free. When we recapture our lightly used water for cleaning and reuse, we don’t use energy to transport that water back to a centralized water treatment facility to treat the water and transport it back to our homes again for use.

Alongside water conservation and water production, water reuse is an exciting solution. We can recycle wastewater into clean reusable water, just as we recycle used aluminum cans into new aluminum cans. This approach is more affordable and sustainable than building new infrastructure. And it releases us from a scarcity mindset around water, ushering in a new mindset of water abundance. 

How It Works

Many do-it-yourself enthusiasts have been experimenting with onsite reuse for years, and there is increasing interest and action around water reuse in the water and building industries. As interest grows, new technologies and solutions are emerging to meet the challenge. There are several approaches to onsite water reuse systems: chemical-based, filtration-based, moving bed bioreactors, and plant-based.

Filtration greywater reuse systems pass greywater through a series of physical filters, such as screens or sand filters, to remove debris and clean the water for reuse. These systems do adequately clean the water, but the filters can clog, and they do need to be replaced periodically. They often need additional sterilization such as UV lights or chlorine.

Chemical-based systems add chemicals such as chlorine to greywater to disinfect it. Again, these systems sterilize water, but don’t truly remove all the contaminants in wastewater

Bioreactor-based systems, including specialized Membrane Bioreactors (MBRs) and Moving Bed Biofilm Reactors (MBBRs),  consist of an aerated tank that cultures bacteria which feed off pollutants in the water. These systems are temperature sensitive and require climate control. The carriers need to be replaced from time to time, and since these systems are sensitive to bleach they can be less resilient than other options.

In plant-based greywater reuse systems, plants and microorganisms absorb and break down contaminants in order to clean the greywater for reuse. There are no filters to clog and no need to add chemicals. The systems are situated outside of the home, so no climate control is required. And unlike simpler bioreactor-based systems, these systems are remarkably resilient. The plants and microbes themselves work together to stabilize the system and recover from toxic chemicals. 

In addition to their technological advantages, plant-based water reuse systems also function at an efficient household scale.

Centralized versus Decentralized

“Water recycling” is a specific term referring to centralized (off-site) solutions where municipal wastewater is centrally collected and treated to drinking standards before being reintroduced into the public water supply.

However, like other approaches to increasing water supplies, centralized water reuse requires massive capital investment. Current regulations require recycled water to be conveyed in separate purple-colored pipes, which forces cities to essentially install a second water grid.

Onsite reuse is decentralized. Smaller systems installed at individual homes and buildings clean used water for reuse, diverting it from the sewer system and giving it a second life onsite. No large-scale infrastructure required.


Onsite water reuse systems can help builders and developers open projects in water compromised areas, an increasing concern in the southwestern U.S. In addition, water reuse systems can help them meet building codes and water conservation regulations, as well as acquire certifications that matter to homebuyers. They can reduce development costs and increase curb appeal. Plant-based water reuse systems, in particular, can add real value, beauty, and comfort to their homes, rather than detracting from it like low-flow showerheads and plant-free landscapes might. 

Water reuse systems can help homeowners reduce their water consumption, comply with water restrictions, and save money on their water bills. In addition, plant-based systems add beautiful landscaping and help homeowners reduce their carbon footprint.

For communities, onsite water reuse systems create scalable decentralized infrastructure that lowers utility costs for all, extends limited water supply, and increases the community’s climate and drought resilience.

Onsite greywater reuse is a hopeful new solution to growing water scarcity, offering multiple benefits to builders and developers, homeowners, and communities. It’s an affordable, sustainable approach, making the most of our natural resources right now and for generations to come.

Learn more about our all natural, plant-based water reuse systems.