On Monday, 28 May 2018 17:23:00 UTC+1, Graeme wrote:
This morning's fun and games.

We have two walls that meet at 90 degrees, one single storey, the other
two storey, both have gutters with downpipes leading to a single drain
gully, where they are joined by a third pipe, from the kitchen (sink and
dishwasher). Both gutters overflow, so downpipes almost certainly
blocked. The kitchen waste works fine. I have to admit that this is a
job that should have been done last summer ...

So, the gully. Usual raised surround, absolutely stuffed with leaves,
mud and general crap. Used a trowel to clear that lot, and saw why the
kitchen waste works, but the other two don't. The kitchen pipe goes
through a hole in the grate, but the other two terminate above the
grate. The open ends of both the downpipes, which terminate below the
level of the crud just removed, were stuffed. Kept poking at the end of
the two storey downpipe until a tiny amount of water began to trickle,
so kept going and suddenly a thick mass of mud and leaves shot out,
followed by two storey's worth of the most foul smelling water I have
ever encountered, which of course splashed over everything including me.

Oh well. The second downpipe was more stubborn, but much poking with a
bent coat hanger eventually achieved the same result. Much flushing to
clear the remnants and both gutters now running freely.

Dirty, smelly, but delighted :-)
--
Graeme

Foul water(from the kitchen should not be going into the rainwater drain.
The crap from the kitchen has probably blocked a soakaway.