Water has definitely been the limiting factor in my garden so far. I live in a rooftop walkout with a fire escape and a strip of soil between a wall and a parking lot. Lots of hot sun on red brick / black tar and not a single faucet to be seen. I've made do relying on the rain and my watering can so far but trekking up and down a flight of stairs is a pain so I've kinda neglected the ground level plants and I've noticed the drought stress has led to alot of insect problems.
I've been trying to figure out a solution to my problem and after taking apart my kitchen sink I realized that the sieve-like adapter was removable - leaving threads, but unfortunately different sized threads than your average garden hose. A quick trip to Home Depot solved that problem: for $6 I got a threaded faucet -> hose adapter and rubber gasket. I would have been content hooking up a simple straight hose to the faucet but luckily my parents recently downsized their house and my dad generously donated his huge reel of garden hose! It has a simple short hose that attaches from the side to the faucet and a spool of hose that is easily long enough to walk across my roof, down the stairs and probably even around the corner! Plus as an added bonus, when the hose is all put away it makes a great extra seat in my kitchen, although a little low for the bar!