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GreyWaterSolution – Realizing the potential of greywater


Awarded for

GWS established a low cost stand-alone solution that used recycled shower water for flushing water in toilet. It reduces water use by 25 %, and recycle greywater in a sustainable way.


GreyWaterSolution is a Danish startup that started in 2019. The company will changing the mindset about greywater. Greywater is not a waste product that needs to go to waste water plant. It can be cleaned local in an eco friendly way, and be recycled. Also there is a lot of heat that can be recycled local. GWS har developer Blue Flow that is a low-cost stand-alone system, that recycle the shower water for flushing water in the toilet.

GWS has also runed pilot test on central greywater systems with sewer heat exchanger. The exchange rate is 25-85% heat recovery.

4 billion people lives in areas were with water scarcity, so why are we not recycle more?


How the innovation was invented

During the construction of some apartments, Morten Vestergaard noticed that even on new apartments, the greywater was just running down as blackwater. At the same time we flush 10t liters of clean water every year in toilet. The idea was born: Why not recycle this greywater? After a lot of test he found out that if we take the clean part of the greywater, it doesn’t need to be added chemical for disinfection. The company then developed a sensor that could detect the water quality, thus using significant parts of the greywater for flushing water.


GWS solution Blue Flow is a low cost stand-alone solution that reduces water use in an average household by 25 %. That is apx. 10.000 liters per person a year. Because GWS only recycles the clean part of the greywater, they are able to clean the water without any chemicals. This is a giant step to more sustainable water use. Last but not least, because the greywater is inside the house, Blue Flow can reduce the energy consumption for pumping by 73 %.



Morten Vestergaard
Rosenvænget 2
8541 Skødstrup

Phone: +45 40569625