Nightjar posted
On 17/08/2018 07:49, Handsome Jack wrote:
...
How do I make the outflow cleaner without replacing or modifying the
tank or drainage field?

If you have an existing drainage field, you don't need to.


I think I have (it wasn't me who built it in the 1930s) but I don't know
if its eventual outflow to the stream is clean enough to meet the new
standards.

--
Jack