The problem seems to be that;
Nextdoor's dog is out of control & killing Millet's bees.
Why?
Because the bees are drawn to the dripping tap.
So stop the tap dripping.
Is the problem solved?
apparently not!
However, the bees are also attracted by the "piss in/on the pots". So we could consider that the dripping tap is not nececarily root cause.
So, Nextdoor's dog is the out of control & killing Millet's bees.
Why?
Because the bees are in nextdoor's garden & anoying the dog.
Why?
Because the bees are drawn to things in nextdoor's garden.
Why?
Because the bees need a local sorce of water & the tap or pots are "local".
Why?
Because the bees are only over the fence from nextdoor's garden.
Why?
Because the bees are in Millet's Garden.
Why?
Because Millet put them there.
Why?
Because Millet didn't consider the tap, pots or his neighbours when he decided to put the bees in his garden.
Why?