I speak a lot about rainwater harvesting on this site, but what about greywater harvesting, or greywater recycling?

This can become a lot more complicated and involves a great deal more filtering which can make your greywater harvesting system very expensive. The funny thing is before I started down this road of researching water harvesting for the home, I always thought greywater would be the one you treat and use in your home whereas rainwater is waste and is best used in the garden. The total opposite is in fact the case, but there are still some difficulties with using greywater. Let’s have a look at the pros and cons of greywater recycling.

What is greywater?

If you have a look at your piping outside your kitchen and bathrooms you will see two different diameter pipes. The larger one is the soil pipe and is connected to your toilets and goes straight into the government sewer system. The narrow one is your waste pipe and these are connected to your shower, bath, basins, kitchen sink, washing machine and dishwasher, and the water is sent down an open drain to the sewer system.

The water that goes into the smaller pipes is your greywater. However, depending on the system you have installed or thinking about installing, not all of this water can be recycled. Water from your kitchen sink and dishwasher are still considered blackwater.

If you have a basic greywater recycling system that will filter the water for larger contaminants and debris then you can take the water from your shower, bath, basins and even your washing machine. You can’t, or shouldn’t however use the water from your kitchen sink as it contains a lot of fats and greases that can’t be removed by the filtration system, unless you have accounted for this and put in a much smarter system.

Also you need to use the recycled greywater within 24 hours to prevent bacteria from growing in it, even after it is filtered. Again this all depends on the system you have set up. Let’s have a look at it in more detail.

In the home

With the basic greywater recycling system that is filtering out debris and should be used within 24 hours, you can reuse it to fill your toilet cisterns. There is also a possibility of using it for the washing machine, but I wouldn’t take it any further than that.

Although it will filter out debris and some contaminants there are a lot of soap products that get used and many chemicals that will not get filtered out. You should by absolutely no means drink this water. Therefore using it in basins, sinks, and baths where you might drink the water is a huge no-no.

If however your system is a little more advanced and you are filtering the water properly and treating it for storage where it is removing all contaminants and being treated against bacteria and other things, you could use it for drinking water and use it right through the house. A system like this is however a massive cost and may not be worth it if you consider it from that view-point.

There are also places that discourage the recycling of greywater, especially to this degree, because the governments need the greywater to return in order to replenish their storage.

Considering all of the aspects of costs and recycling, going with a system that will be used in your toilet and garden is probably the better route to take. This will reduce your water costs, not hugely but it will have a noticeable impact.

In the garden

The best place to recycle your greywater is into the garden. However there are some aspects that need to be considered.

You cannot take the greywater and use it directly on the garden without it first being filtered. In some places this is illegal, such as in NSW, Australia. Consider what the water would contain. What do you use in your bathroom that goes down the drain? Soaps, creams, and if you happen to use chemicals to unblock your drains.

It is a good idea to research what products you can use that have the lowest negative impact on the environment and then use those.

Another problem with using greywater in the garden is pumping it through an irrigation system as it can often clog the sprinklers. This is where you need good filters, or you could set up drip irrigation, which won’t clog as easily, instead of a sprinkler system.

Now that I’ve scared you into not using greywater, naughty me, let me just say that it’s not all bad. There are in fact some phosphates in soaps and detergents that are very healthy for the soil and act as a great fertilizer. However greywater can contain a lot of salts which can build up in the soil and create a barrier, so it is advisable to check what you are using in the house and what would go into the greywater.

If you see that your plants are getting burn spots you might want to check your laundry detergent. A lot of them use boron which is a necessary mineral, but it can quickly become toxic.

Separating the supply

If by chance you want to use your grey water for your garden and for domestic use, then you could consider splitting the resources.

Once it has gone through a filtration process, and I mean a good one, you can channel it into two separate collection tanks. One would be used for your garden and toilets, which is not treated and therefore needs to be used within 24 hours. The other can be used for everything else and therefore needs to be treated.

The treated water, usually with chlorine bleach, can’t be applied to your garden because it will just kill everything. However the treated water can be used in the house and can be stored for longer than 24 hours.

Again, look at the costs involved and make the decision as to whether it would actually be worth it in the long run. You may be better off creating a rainwater harvesting system that you can filter, treat and use inside the house. There are far more chemicals and bacteria in greywater than in rainwater.

Some other issues

Have you considered the smell of greywater? If it has been filtered and is used in 24 hours, there won’t be a problem. However if it is left in storage without being treated it will stink up the place.

The maintenance you need to do on a greywater recycling system is quite a lot, especially considering that greywater is “dirty” and therefore will require lots of cleaning. For instance should hair get wrapped around the pump it will cause the pump to not work at full capacity which could in turn cause water to get into the pump, shorting the system and possibly causing electrical shock through the water.

If your filtration system does fail you could risk contamination which is a huge health hazard. I don’t mean that just for the environment, I mean that for you and your family.

And some advantages

Consider the way the planet is going. Water is becoming one of the most valuable natural resources available, especially with the current water shortages affecting a lot countries.

Incorporating a greywater recycling system as well as rainwater harvesting will reduce your impact on the environment, will save you a lot of money and will increase the value of your home.

Not to be all doom and gloom, but in the United States alone the population growth is expected to be 420 million by 2050, which means water is going to become a rare commodity.

Cape Town in South Africa recently went through a water crisis and ran out of drinking water. They are still recovering.

In 2012 it was estimated that 36 US States would run out of water by 2015. In 2015 it was estimated that 40 states would have water shortages in the next decade.

Now that it is 2018, going into 2019, what is our water situation like worldwide? For more information about the current worldwide water situation, head over to the article on the National Geographic site which is about the world’s water crisis explained on World Water Day, publishing in March 2018.

In conclusion the more I research greywater recycling, the more impractical it seems to become. Personally I will be sticking with rainwater harvesting, and that will make up the main chunk of this website. However that doesn’t mean I don’t realise the importance of greywater recycling, and I may change my mind in the future.

With the impact on our environment and the possibility of climate change, rainwater harvesting may in fact become less important than greywater recycling in the future. Yes I know, doom and gloom again and I’m not one of those insanely eager survivalists that dig bunkers in their backyard, but I have been on this planet long enough to experience the climate changes that have happened over the years. If that continues to get worse, we might not get enough rain to sustain us.

Currently though the best way to use greywater recycling is to filter your bath, shower and basin water, and pump it into your toilets and for drip irrigation. Why we use drinking water to flush our toilets in the first place is a whole other question. Did you know that on average, 25% of the water entering your home is used to flush the crap down your toilet?