Pulling together some of the ...

Pulling together some of the things said already, grey water from baths, showers, sinks etc. is generally safe for garden watering (as long as you're not going to consume fruit/veg shortly after watering) and for flushing toilets. There are a couple of points to note:

• The organic residuals in grey water mean that the toilet and cistern are liable to get dirty over time. 
• The recycled water pipes need to be clearly marked to ensure nobody connects into the pipes for other purposes (such as to add a potable water tap!)
• Filtration may be useful to prevent fibres or small solids blocking the fittings / spray heads.

Disinfection of greywater for these purposes is not usually necessary. Any pathogens in greywater are going to be present in your soil, and if you're flushing your toilet with it then any aerosol generated during flushing is liable to contain traces of pathogens anyway. There's a small risk if spraying grey water onto the garden, but fairly minor.

Recycling automatic washing machine water for these uses is generally NOT recommended because the detergent is much more concentrated and it should be treated as black water instead.