How and Why to Reuse Greywater

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As a homesteader, two of my main goals are to use every resource I have to its fullest and save as much money as I can. One of the best ways to do both of these is to reuse greywater. It beats letting it all go down the drain, right? Reduce, reuse, recycle!

What is Greywater?

Greywater is wastewater from your household that hasn’t been in contact with human waste. It comes from the bath, shower, bathroom sinks, and (laundry) washing machines. Many sources say that since wastewater from the kitchen sink and dishwasher can contain heavy loads of organic material, fats and caustic additives, they should be deemed as blackwater and not reused. Typically, 50-80% of household wastewater is greywater, and can be reused.

Why Reuse Greywater?

Many areas experience drought-like conditions in the hot summer months, which leads to water restrictions. With heavy watering restrictions, your water could be shut off at certain times of the day, or you could be fined if caught using water outdoors “unnecessarily.” By reusing greywater, you avoid this problem altogether. If you’re on city water, you’ll save loads of money on your water bill reusing your greywater. Likewise, you may save valuable resources if you’re on well water. Using greywater also reduces the strain on water treatment facilities. Reusing greywater is good for the environment and your wallet.

How to Collect Greywater

There are multiple ways you can harvest your greywater. It can be as simple as placing a plastic bucket under your bathroom sink to catch what goes down the drain, or as complex as a $10,000 greywater collection, filtration and pressurizing system. The more advanced the system you have, the more applications you can use the water for – some systems actually filter the water enough for consumption!

If you’re good with solar power conversion, you could use solar energy to run a greywater filtration system and save up to 40,000 gallons of water a year. Reuse greywater from your washing machine, sinks, showers and tubs to irrigate your garden every day, even during water restrictions.

Other ways to collect and reuse greywater:

  • Save unused drinking water. Instead of dumping out that half-full bottle of water that’s been in the car for a week, pour it onto your plants, or pop it into the fridge and drink it. If you’re worried at all about drinking it, you can pour it into a filtering pitcher to keep in your fridge.
  • Place a bucket in the shower while you’re waiting for the water to warm up and use that water to directly water your plants, flush your toilets, or even use it for drinking. If you want to filter this for drinking, you may need a bigger filter.
  • Wash your dishes inside a dishpan instead of directly in the sink, then take the water to the garden or compost pile – the soap will actually help control pests!
  • Wash fruits and vegetables in a dishpan, as well, instead of under running water. Use a little vinegar to help clean the veggies and keep them safe for eating, and use that water in the garden as well.
  • Capture the rinse water from your washing machine in a large Sterilite container, run it through a filtration system to remove any possible harmful chemicals from the laundry detergent and mix that water into your rainwater cistern to use for irrigating your plants and lawn. If you make your own laundry detergent, you won’t have to worry about the filtration so much.
  • Use a siphon pump or bucket to scoop out your water after a bath, and use that water to flush your toilets by pouring the water directly into the bowl.

Where to Use Greywater

Many places in Europe, Australia and the United States that have adopted the International Plumbing Code (IPC) are already using greywater to flush toilets. The IPC protects public health and safety in buildings for all water and wastewater related design, installation and inspection by providing minimum safeguards for people at homes, schools and workplace. Check with your local Department of Public Works to see if your area is able to use greywater in toilets.

Another way to reuse greywater, and probably the most common, is for plant irrigation. Do not apply greywater to crops that you will eat raw, such as strawberries, carrots or lettuce. For general health reasons, you might think twice about using greywater on any vegetables. Greywater is perfectly fine for fruit trees where the crop is far from the ground and there is little to no risk of direct contamination by contact with contaminated water. It is best to use greywater in a drip irrigation system instead of spraying directly onto plants.

Government Regulation of Greywater

As the risks and benefits of using greywater for domestic landscape irrigation are being defined, government regulation is continuing to gain more support.

According to Wikipedia:

‘Greywater’ (by pure legal definition) is considered in some jurisdictions to be ‘sewage’ (all wastewater including greywater and toilet waste), but in the U.S. states that adopt the International Plumbing Code, it can be used for sub surface irrigation and for toilet flushing, and in states that adopt the Uniform Plumbing Code, it can be used in underground disposal fields that are akin to shallow sewage disposal fields.

Be Safe! – It is always best to completely research the use of greywater from multiple sources including your local water authority to be sure it is being done properly.

Do you reuse greywater or know someone that does? We’d love to hear your stories!

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