Vent: I laughed at my neighbor's rain barrel setup for 2 summers, then Phoenix got that 31 day dry stretch
I told him catching roof runoff was pointless here since it evaporates in a day, but he buried a 55 gallon drum with a shade cover and it was still cool water in August. Now I'm hauling buckets from his spigot like a chump, so what's the real catch with these setups, does the water go bad if it sits?
still cool water in August" is the whole trick right there, the buried drum stays around 70 degrees while surface water hits 100+. Water doesn't really go bad if it's covered and dark, but you get algae fast if any light gets in and mosquito larvae will show up in the first week if the intake isn't screened. Toss in a cap full of bleach per 50 gallons if you're just using it on plants, or run it through a hose filter if you want it for anything else.