Regulators are also concerned with high nutrient loads in greywater. Research in Australia and America shows this to be unfounded in households which do not use phosphorus-containing detergents. Local councils can choose to override state regulations, and this has occurred in some unsewered areas of Australia. Encouragingly, direct greywater re-use for garden irrigation is now being examined by some Australian water authorities as an option for reducing fresh water demands in rural and urban areas. In January 1996, the Queensland Department of Primary Industries released a Policy Options Paper on the Use of Greywater, which examines the potential for regulated re-use of greywater in sewered and unsewered areas of Queensland.
Diseases are potentially present in used house water only where occupants are ill.
An important study by the Los Angeles Office of Water Reclamation in 1992 monitored eight greywater re-use systems for a one year period in the City of Los Angeles. The study concluded ' the use of gray water at the pilot project sites does not pose a significant risk to the users or the community '. There have been no recorded cases of people in Australia, America or Britain ever getting sick from contact with greywater re-used in the garden. To spread disease, people must come into contact with the contaminated water. With sensible greywater management, this should never happen because greywater should only be applied beneath mulch or soil.