For me it's a case of having too as the type of vac I use on some jobs would not get it back in the van even using loading ramps.
I always ask to dump it first in a convenient part of the client’s garden as its very good compost. Just have a look around before asking for a suitable area to empty the drum like a composts area, on boarders, in/behind a bush or tree etc. If dry can be bagged up and left with them to get rid either the bag/s emptied into a green garden waste wheelie bin if they have one or dump the bagged up crap straight in their black bin. Any sods etc that don't go into the drum they would be disposed of the same way.
On some jobs were there is loads of sludge/water in the drum I may also find a suitable convenient drain to drain off the water first before emptying the drum.
Whilst in the process of clearing gutters when the crap starts sticking to the inside of the poles, hose etc and becomes noticeably heavy I tend to stop and with all the poles, head and hose assembled will fill a bucket of water say half full and suck water through the guttervac so everything is clear again. I also tend to do this then empty the drum at the end of each job so the guttervac is ready for the next job.
I've also been known to empty the vac discreetly during/after a job in say a convenient hedge row on common ground too. Doing this has no environmental impact whatsoever as is just organic waste so the risk of getting fined would be very low.
I've also had strict instructions from my missus not to bring any more gutter crap and/or block paving sludge home as our borders are like 10 foot tall now
