How to water recycle

Wastewater reuse

On-site wastewater reuse can reduce water use in both urban and rural households. At present, most homes use potable (drinkable) water for practically everything in the house and garden.

We are literally flushing our drinking water down the toilet!

The articles Reducing water demand, Rainwater and Outdoor water use also have information on reducing potable water use.

Opportunities to reuse wastewater and regulation of its treatment vary according to where you live. Urban households typically have a connection to a centralised, or reticulated, sewage system, whereas rural households manage their wastewater on site. Check with your local council or state health authority for advice on the regulations in your area.

Two types of wastewater are created in a home: greywater and blackwater.

Greywater is wastewater from non-toilet plumbing fixtures such as showers, basins and taps.

Blackwater is water that has been mixed with waste from the toilet. Because of the potential for contamination by pathogens and grease, water from kitchens and dishwashers should be excluded from greywater and considered as blackwater.

Each wastewater type must be treated differently and can be used in various ways. Greywater is ideal for garden watering, with the appropriate precautions, such as using low or no sodium and phosphorus products and applying the water below the surface. Appropriately treated greywater can also be reused indoors for toilet flushing and clothes washing, both significant water consumers.

Blackwater requires biological or chemical treatment and disinfection before reuse. For single dwellings, treated and disinfected blackwater can be used only outdoors, and often only for subsurface irrigation. Check with your local council or state health department on local requirements.






While recycling is a term generally applied to aluminum cans, glass bottles, and newspapers, water can be recycled as well. Water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin (referred to as ground water recharge). Water recycling offers resource and financial savings. Wastewater treatment can be tailored to meet the water quality requirements of a planned reuse. Recycled water for landscape irrigation requires less treatment than recycled water for drinking water. No documented cases of human health problems due to contact with recycled water that has been treated to standards, criteria, and regulations have been reported


Every year during summer, India appears to be on the verge of a water crisis once again despite witnessing bountiful rains the previous year. Recently, Bengaluru’s worsening water woes made it to the headlines, with scary statistics warning that India’s IT capital would go the Cape Town way if  preventive action is not taken immediately.

As JA Carney wrote in her 1845 poem, little drops of water and tiny grains of sand make up the mighty ocean. And its past time that we Indians started saving those precious drops. One of the most effective ways of doing this in everyday life is greywater recycling, a method of recycling wastewater from kitchen sinks, showers and laundry fixtures.

Here is all you need to know about this simple, safe and sustainable water-saving system.

Why is greywater recycling so awesome?

Greywater recycling helps reduce household water usage by about 50% — potentially halving your water bills as well as your water footprint.

It is also a smarter use of resources. When you use greywater to irrigate your plants, you’re getting twice as much good out of that water. First the bath; now the garden.

Furthermore, when you clean it on-site, you are reducing the effort and infrastructure invested in moving this water to a treatment facility far away. By not sending polluted water, you are also preventing lakes from frothing and catching fire.

Moreover, unlike a rainwater harvesting system (which relies on rainfall), greywater is in plentiful supply on a daily basis — the more clean water that you use to wash yourself, your food and your dishes, the more greywater you will have to recycle.

Advantages of reuse

By using wastewater as a resource rather than a waste product you can:

reduce water bills
use fewer water resources
irrigate the garden during drought or water restrictions
cut down the amount of pollution going into waterways
help save money on new infrastructure for water supplies and wastewater treatment
decrease demand on infrastructure for sewage transport, treatment and disposal, allowing it to work better and last longer.

Disadvantages of reuse

The disadvantages of reusing wastewater also need to be considered. Currently, the main disadvantage for most households is the financial cost of installing and maintaining a reuse system. The attractiveness of the investment would depend on:

the extent of centralised wastewater treatment services available
the price of water in your area (urban) or scarcity of water (rural)
whether you are replacing an existing system or starting from scratch
the length of time you intend to live in your current house
the type of system — annual operating and maintenance costs vary between systems
whether a restriction free, reliable water supply is valuable to you — wastewater reuse is often a much more reliable secondary source of water than common rainwater tank installations (see Rainwater).
If your house is frequently unoccupied for a fortnight or more, for example a holiday home, select carefully to find a reuse system that can cope with intermittent use. Most systems that include biological treatment do not function properly if used intermittently.