On 4 Dec, 10:18, "Cerumen" wrote:

Anything that does not do that is a cesspit rather than a septic tank in my
opinion and they need emptying when they are full which of course depends on
usage.

It was my experience in Lincolnshire before mains sewage that a
properly made septic tank, brick built and cement lined, will work
without needing any significant attention at all. And I agree that
the design is difficult - do you include the grey water to keep the
working volumes up, or do you restrict it to blackwater and rainwater?

Ten year intervals for sludge removal springs into my memory. And,
because of the placement of the tank, a sucker tanker was never an
option. Bucket and barrow, that's the stuff.

A proper septic tank is IME quite large, and needs a substantial space
for a soakaway. The small plastic round type seem to have a different
bacterial mechanism, and really do have to be sucked out quite often.
I think this is the main reason they are so near the house - for easy
access from the road.

As to cleaning costs, I am not surprised at £120. At one time sucker
tankers would be emptied on adjacent farm land, but now licences are
needed for disposal and special licenced dumps for the stuff to be
taken to. HSE gone mad. Don't know what the bucket and barrow
brigade now do.