"The Natural Philosopher" wrote in message
...
How often does a septic tank need to be emptied of solids which don't
fully rot down, even though the majority of the liquid is discharged
(after processing) into a soakaway?

Depends how much **** and how many sanitary towels you put in..

OK. Two adults. No sanitary towels etc - indeed we are careful to abide by
the "if it's not gone through you, don't put it down the loo" rule, as well
as only using washing up liquid, toilet cleaner and dishwasher tablets which
say they are dishwasher-safe.


Where we lived before, several houses shared a common drain to the sewer in
the road. It was always getting blocked - luckily a fair way downstream of
us so the manhole that became full (or overflowed) was in someone else's
garden. The guys from Yorkshire Water found a huge blockage of tampons. My
wife doesn't use them, and the two other couples on the same drain are
elderly so well beyond needing them. But one of the other couples had their
teenage grand-daughter to stay from time to time... To avoid singling anyone
out, Yorkshire Water sent the same letter to us all, saying "don't put
tampons down the loo" but we all knew who it was intended for ;-)