We put in a 4000l spetic tank 2 years ago and apart from some smell as
it started up it has performed flawlessly and waters the orchard in dry
spells very nicely. You are meant to empty it out every 5 years but in
my previous years of owning these I have never done this and never had
problems with them. Only thing we have to do is make sure the mother in
law does not use bleach and make sure people know they shouldn't put
sanitary towels down the loo. The worst bit is that we empty the grease
trap every year which is a truly awful job and one that tends to have a
very strict rotation as to whose turn it is!