I’ve not come across any blocked downpipes I’ve not been able to suck clear.
While blocked downpipes are fairly rare, the outlet that joins the roofline gutter with the downpipe can often become clogged and blocked as gutter clutter floats naturally toward it.
Gravity normally clears the vertical pipe, but all sorts of gutter junk can block the opening where the downpipe meets the roof gutter.
We recently cleared an industrial unit. Extra wide and extra deep compared to domestic gutters because all that rainwater that lands on the big roof has to go somewhere.
Two thoroughly blocked downpipes meant that the water was overflowing at the lowest point of the run, unfortunately that was over the doors.
I sucked over 300 litres of leaf litter and standing water out and customer just reported that the gutters are no longer overflowing and water is running freely as it should.
Customer comment: ‘.. made a massive difference to our gutters, we would have been overflowing in this weather’