If water has untreated ...
Published by Abba Niv, Drainage Engieer at Zafrir Weinstein Engineers PM
If water has untreated sewage, or partially treated sewage it will be not fit for irrigation. If the grey water does not have any sewage 0%!!,it should be tested by a water lab to check the presence of salts, Ca, Na, Cl, SO4, Mg, HC03, CO3. When these are present they may cause problems with the soil as well as affecting crops.
Grey water may be used for golf courses, parks or lawns but still checked for salts.