Greywater for toilets?

Question

Is it possible to have the greywater form your shower and laundry be piped back into your house to be able to flush your toilets?

The water would go from the shower or clothes washer to a big underground storage tank, to be piped back for toilet flushing use.

Will there be bad smells from the water or health issues? Since the water could be stored for quite some time. Also will the toilet water be cloudy? And could a filter be put before the water goes to the toilet to help this? If so what type of filter?

I have no experience with some thing like this but would like to see if I can implement it to help save water.

Answer 1

that is exactly the system we use in my 125 unit condo complex....save the shower and sink water to a tank, treat it with chlorine periodically and then pump i t back to flush the toilets.....and then treat the sewage to use the resulting bacteria free water to water the plants and flowers, but thats another story...

if all you are putting in the tank is shower and washing machine water ( no food to rot and bred germs) you might be able to skip the chlorine step...experiments will tell!... and you can also use that shower and washing water for irrigation......

you may also want to run the water thru a U.V. sterilizer like a SANITRON unit.......great technology....

Answer 2

my mum has a grey water toilet system and it also goes out to a tap outside so she can water the garden and wash the car.

i havnt really had a look at the flush water, but it doesnt smell

Answer 3

First, your idea to reuse wastewater prior to disposal is an excellant idea for water conservation. Many municipalities are implementing the concept of reusing treated wastewater in order to reduce the demand for fresh water supply.

To answer your specific question, yes there are grey water systems out there where shower/laundry water is routed to a storage tank for later use.  Some municipalities actually require new homes to have dual plumbing for this purpose.  Typically, the collected grey water is used for irrigation of lawns.  There are issues with storage of grey water that does include odor, color and solids build-up (lint, hiar, soap scum, ect).  However, treatment systems can be designed to mitigate these issues (possibly chlorination and sand filtration treatment).  

If you add a treatment system for your grey water, then other water conservation measures will be likely be much more cost effective.  Low flow toilets and shower heads are common and now dual flush low flow toilets are entering the market to further reduce bathroom water use.  

In most areas, outdoor use of water is much larger than indoor use (30% indoor/70% outdoor for example)  So, in these areas, greywater systems for irrigation of lawns makes the most economic sense.  However, there are areas where indoor use is higher than outdoor use - these areas tend to be in regions where water conservation has a long history.  In a region like that, your idea may help further reduce the demand for fresh water supply.