The choice of individual homeowners will depend upon lifestyle, size of garden, site layout, climate, available finances and other factors. Some basic parameters should be adhered to whatever system is used. Storage of greywater should be avoided where possible. It is best to apply greywater beneath mulch or soil. This stops the possibility of greywater pooling on the surface where children and pets can play in it or mosquitoes can breed.
Direct contact is virtually the only way for people to get sick from greywater re-use.
The easiest way to apply greywater sub-mulch is to position greywater outlet points in swales or mulch basins then cover with mulch. Applying greywater beneath mulch means the greywater must soak through topsoil where micro-organisms and roots are most active. This biologically active soil facilitates destruction of any pathogens, breaks down organic matter and utilises nutrients in greywater. Both bathroom and laundry water are generally far less polluted than kitchen water, and so are easier to re-use. Remember that kitchen water pollutants are mostly compost, and if applied directly to soil under mulch, should decompose quite rapidly.