Recycling Kitchen Grey Water

I have been interested in the subject of grey water ever since I had a water meter installed in 2009. After  extensive research on the subject, I have installed a WaterTwo water diverter valve to collect my kitchen grey water.

Most people harvesting grey water install the valve to recycle their bathroom (shower & hand basin) or laundry grey water. And indeed that is where the manufacturer’s website recommends installing it. So there’s my disclaimer on their behalf. But as indicated, I did plenty of research on kitchen grey water and decided I would start my foray into grey water in the kitchen. The kitchen is where I use the most water and where I feel I have the best control over what is in the water being recycled.

Why kitchen grey water?  I am a fastidious washer and rinser of fresh produce and for me, the kitchen greywater was a better option than bathroom shower and basin water. I also think it is a heck of a lot cleaner than my recycled laundry water!

Having said that, I will advise that  using  grey water requires caution – and re-using kitchen grey water requires particular forethought.  If you are a cook that does a lot of greasy cooking or uses harsh chemicals, it is definitely not recommended. If you are someone like myself, however, who doesn’t fry things and uses only organic bio-degradeable washing liquid and vegetable wash, then you could easily harvest your kitchen grey water to reuse in watering your plants and garden. Grey water should not be used on vegetables that are eaten raw (e.g. lettuce) and due to possible pathogens, all grey water should always be dispersed onto the soil, not onto the plants themselves. Never use greywater that has been used to wash meat or fish, nor when you have cleaned your sink using anything other than a good organic biodegradeable cleaner.

Use Bio-degradeable Cleaners

The three products that I use are Nature Clean’s Fruit & Veggie Wash (a Canadian product), EcoVer dish detergent, and Shaklee’s H2O cleaner.

How I installed the kitchen grey water diverter valve

After a lot of thought I decided to install the diverter valve on only one sink. This allows me to pick and choose which greywater ends up in the water butt. Basically I reuse water that has been used to rinse fruit and vegetables, dish water from very lightly soiled dishes, and the water that runs down the drain as we wait for the water to get cold for drinking, run off when filling and emptying the kettle, etc. – in other words, nothing that is very dirty or greasy. Many people do use more soiled water with great results, but I am new at this, am taking it slow and currently do not.

The diverter valve is installed on the small centre sink:

When the valve is open the water drains into the water butt (via the green hose), and when closed the water drains down the regular drain and back into the council system.

Here’s what it looks like under the sink. The white gunk is just silicone to ensure a tight seal.

Filtering the water

I  use a homemade three-filter system – a big plastic strainer to catch the big bits (which are then popped into my compost)

a smaller wire mesh thingy that sits on the drain hole

and a fine mesh that covers the end of the pipe (it is actually made from old pantyhose).

Do you wash dishes in that tiny middle sink?

No. I use a plastic dishpan in one of the bigger sinks, and provided the water doesn’t look too nasty, I pour it into the centre to be recycled.

More information / links on grey water

• Using grey water
• If installing a grey water diverter valve in the kitchen you should a) plan to use the water pretty much right away and b) have a mesh bag over the end of the exit hose to filter any tiny food bits. Most kitchen grey water users that I have encountered run a hosepipe out to the garden, where the water is immediated dispersed onto vegetation. At the bottom of the page is a video showing someone else’s drainage system:You CAN get away with storing well-filtered grey water by adding household bleach to the water butt, but using it immediately is the safest route to go. If you go that route (storage) you will need to research the ratio of bleach to be added per litre or water. Google is your friend 😉
• Collecting, storing, re-using grey water
• The WaterTwo Diverter Valve website
• And finally, this is an example of how others have created a direct kitchen grey water drainage system: