On Thu, 01 Apr 2010 04:54:03 -0700, wrote:

I don't believe there is a regulation distance for non habitable
wotsits.

But you shouldn't build over either the pipework or the drainage field.

Although the pipework always has to get from inside a building to the
outside world - I don't think that's so much of a problem so long as
there are access points for cleaning. Agree about not putting anything
over a drain field, though (and if building above pre-existing pipework
there are probably ways and means of doing it so that the pipework isn't
damaged even if the foundations settle a little).

Guy next door to us has a tank about 8' from the outside wall of his
workshop (but no drain field, just a tank) - no engineering problems
anticipated in doing that, but that is in the US where there are no
building regs to worry about.

cheers

Jules