This is "Barrel 1". It is the primary barrel and is fed by the flexible downspout from my roof gutter. The downspout simply pours into the top of the barrel which has a screen top with a perforated plastic support insert. Sometime junk from the gutter collects in the top of this barrel and I just have to gather it and put it in the compost pile.
I drilled a hole in the top of the barrel to accommodate the fittings that I got in the plumbing department of the local hardware store. The fitting slips into the hole and has a screw on piece that hold it in the barrel. The hose then fits onto the outer piece which has barbs on it to hold the hose in place. Works pretty well. I wish that I had drilled my holes a little lower as the angle of the fitting and the arc in the hose means that the water level needs to be above the arc before the overflow begins.
During the first rain I had to adjust the hoses a bit to make it work better. Some wire and an old tent spike wedged under the hose pulls it down just enough to make it work better. The other option is to have more height difference between barrels.
This next photo shows "Barrel 3" into "Barrel 4". The tops of "Barrel 4" and "Barrel 5", my two steel barrels, are made of window screen stretched over the opening and held on with bungie cord. It is important to keep mosquitos out of your barrels. This will do it! I also like that I can open the steel barrels and soak my mushroom logs in them. The openings on the plastic barrels are too small for log soaking.
The steel barrels were scavenged but the plastic barrels were purchased at out local healthy grocer, EarthFare. They came outfitted with spigots and cost $70 each. The parts to connect them all cost about $30 from the hardware store. I figure that the savings on my water bill will cover this well within the first year. Not to mention that my plants are happier without city water and I am doing my small part to conserve resources.
The barrels each hold approximately 60 gallons. So together they give me about 300 gallons. Because I have such a drop from the collection site and the garden, which is below... I can hook up a hose with a sprayer to a barrel and run it down hill to the garden and have a gravity watering system.
Generally I only water what needs watering and use a large amount of mulch to keep watering needs to a minimum.