Why irrigating your garden with laundry greywater is a bad idea
For the sake of the soil in which your plants must grow and thrive, think twice before deciding to re-use laundry greywater in your garden.
If you really want to use it as part of your greywater system, at least then chose liquid washing detergent over washing powder, as it still degrades the soil, but not as much. That is the message from soil scientists at Stellenbosch University, who published the first ever comprehensive research on the topic in the Journal of Hydrology.
here: Impact of powdered and liquid laundry detergent greywater on soil degradation, by Ailsa Hardie, Ncumisa Madubela, Catherine Clarke and Eugene Lategan