The best replacement for downspout is down spout.

The best alternatives to downspout are rated as following:
★★★★★  down spout

Your alternative for downspout is not listed? Suggest!
Speaking about downspout, one probably shouldn't forget about diverter.

Other search terms related to downspout and their ratings are:
★★★★★ diverter
★★★ rain barrel
★ gutter
You have in mind a companion for downspout and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of downspout in all years. Click on graph for more.
downspout
down spout