Posted: 05/09/2013 at 09:02
Only the water from our Separation type dranage sytem (Septic tank system is different) goes into the field beyond our garden. If there are any germs in it then the wheat/barley/rape seed/potatoes which are grown in there are going to be affected. No, the usual system is such that the grey water sump is deep underground and since gravity pulls the stuff downwards, the chances of anything from the discharge reaching the roots of plants are very small to non-existent.
About the only thing you need to watch is blocking access to the tank. It will need emptying every now and then.