Greywater Recycling Systems

by ‐ Tags: green living, water efficiency

With the severity of last year’s drought, as covered in our most recent blog post, water conservation is important to think about whether or not you live in an area with limited water resources. Greywater - the water used in your home for activities such as dishwashing, laundry, and bathing – can be up to 50-80% of a typical home’s waste stream. The potential savings from recycling greywater are great from both a water and energy conservation standpoint.

Greywater recycling systems essential work by collecting and filtering any water used for washing in the home, which has not been in contact with human waste. The filtration process removes any organic solids and can include a purification step depending on the eventual application of the recycled greywater. The greywater is not stored for longer than 24 hours before usage or drainage to prevent the growth of bacteria. There are a wide variety of sources and uses for greywater:



The most common use of greywater that is not automatically directed to another system within the home is for garden or lawn irrigation. Rain barrels can be used to collect rainwater for irrigation as well, thereby reducing the amount of times you need to use freshwater out your hose. The EPA provides several resources on how to build your own on their website.


Freshwater use in toilet bowls wastes potable water that never comes in direct contact with people. The use of greywater in toilets tackles this issue by replacing the freshwater to keep the toilet functioning while reusing water, which would have headed straight to the sewer system instead. The concept involves either using wastewater from a shower or a sink. Systems like the AQUS Greywater Toilet system have been featured for easy installment and effective use of used sink water. The system claims to save up to 6,000 gallons of freshwater per year with annual maintenance. For a more labor-intensive approach, you can use the greywater you collect yourself from a variety of sources and pour it into your toilet bowl tank.

Greywater recycling system, water conservation, greywater toilet, sustainability


Heat reclamation systems use pre-heated greywater flowing out of the house from activities such as dishwashing or showering to transfer heat to incoming cool clean water. These systems can recover up to 60% of the heat from the greywater, saving you heating energy and money! 

Common concerns with the use of greywater are related to potential toxins and pathogens in greywater that has not been properly treated. If unfiltered or unpurified greywater is misused for purposes that involve direct contact with people, there are risks to public health. These risks have led to government regulations, which require people to get permits from their local health department before installing greywater systems. Plumbing codes vary state to state so be sure to first visit your local government's website to check regulations on greywater discharge and usage before making any large investments!

If you’re eager to start reusing greywater without retrofitting your home or installing a system, learn how to start using your kitchen sink greywater without fancy equipment here. Don’t forget, the stale water from a pet bowl or water after boiling pasta count as greywater too!