Whew. I just finished a project this weekend that has been hanging over my head for the better part of two years now: I've made three rain barrels. These are nice little devices that should be easy to make, IF you have access to the right tap. Getting the tap and die turned out to be time consuming. But the final result is something that should save quite a bit of angst when the drought kicks in, and will also cut back on erosion off the hillside.
So! What is a water barrel, anyways? Simply put, its a catchment device. It intercepts water coming from your downspout and stores it until you are ready to release it at the destination and time of your choosing. This doesn't just help save water during drought. Think about all the water that comes off your roof during a storm. If that all hits the streams and rivers in one rush, as it does when it comes out the downspout and down to the nearest storm sewer, culvert, or stream, it has tremendous power and force. The erosion damage and the nutrient sweepoff kills both the land and the seas. Just one rain barrel on every house in a metropolitan area could save thousands of gallons of water, and at the very least delay and thus soften its impact on the land.
What makes up a water barrel? It's just a plastic barrel with a few additions. Near the bottom, an outflow hose connected to a hosecock permits you to let water flow out into a hose of your choice when you're ready for it. An overflow hose near the top can link serially into additional barrels or can return to where the drainspout had been. On the top, a screened basin (a pond skimmer is ideal) provides a place for your downspout to hook into the system.
The first step in making a rain barrel is obtaining a servicable barrel for the project. Ideally, you want a food grade barrel, but as long as you are not planning on recycling the water for drinking or watering food crops, any clean barrel will do. I obtained my barrels from my local Pepsi bottler - they sold me 3 white 55 gal. barrels for $5 each, and were very nice about it. I've heard of some people who've obtained barrels from a local vinegar manufacturer. They're bulky, so make sure you have either a pickup truck or a minivan or other suitable conveyance available. Bring it home, unscrew any openings (the soda syrup bottle had two plugs that screwed out), and rinse the barrel out with a garden hose.
The next step is the one that took me far too long to complete. The problem was one of access to the proper tool. About three inches from the top of the barrel, one needs to cut a 1 1/2" hole using a threaded tap, and to do the same thing 1 inch from the bottle, using a 3/4" tap. I had the drill bits to put in the pilot holes, but finding the tap and die stock proved extremely difficult. Fortunately, I found a local non-profit that was running a workshop and was willing to let me bring my own supplies and use their taps. Many thanks to the Herring Run Watershed Association. The tap rests at the edge of the pilot hole. Then, using a wrench, turn the tap into the hole and it will slowly cut the threads, deeper and deeper, until it is the proper size to admit a 1 1/2" to 1" male hose adaptor (for the top) and a 3/4" male hose adaptor for the bottom. There is a third hole that needs to be cut into the barrel. That goes on top of the barrel, and is for the skimmer basket to go in - it will be where the diverter from the drainspout enters the barrel. I used a jigsaw, which worked very nicely for the square basket I had. Just cut the hole so that the rim of the skimmer will rest on top of the barrel, with the rest of the basket sitting inside. At the workshop, I saw people using round baskets and a rotozip - cool toys are always nice to have about. Hot glue a little wire screening material to the top, if you are really worried about detritus falling into the barrel - I didn't bother with this myself.
For the hose adaptors, wrap the threads with a little teflon tape. This will help keep leaks to a minimum. For the top overflow hose, I used some flexible black plastic corrigated pipe, also called ABS pipe - it fit right onto the barbed part of the hose adaptor easily. Hit it with a little squirt of clear silicon caulk if you're worried about it being absolutely watertight and enduring. Then for the bottom hose, you've got a physical strength move, pushing the barb over a small length of garden hose. I used two of the adaptors, one for each end. How long you want the garden hose length to be is up to you. I figured that I can always attach a longer piece of hose, so I just used 2'-3' lengths for now. At the opposite end, I threaded a female hosecock onto the male adaptor. That way, I can just turn the hosecock whenever I want to release water from the barrel.
The only other option, which I didn't do, is painting the barrel. If you're going to use this for drinking water, I don't recommend painting. If you just need to water a lawn or such, then go for it! Krylon makes a special spray paint that is formulated for plastic. Go all one color, or call your neighborhood graffiti expert and really have it tagged as special. Just remember that your neighbors are quite likely to see this. Check with the covenants to make sure that it fits in, however it may be decorated.
To summarize - you need (for parts) a 55 gallon barrel - ideally, plastic food grade. A length of garden hose. Two male 3/4" adaptors and one male 1 1/2" adaptor. Two worm hose clamps. Teflon tape. Silicon caulk. A skimmer basket. You can add screening and paint, if you care to. A length of 1 1/2" corrugated pipe (ABS). For tools, you need a jigsaw, or you can use a rotozip if you are using a round skimmer basket. You need a drill, a wrench, two bits (3/4" and 1 1/2" - I used a spade type, but a hole saw type would work nicely also, and two taps (3/4" and 1 1/2"). A screwdriver is good for the worm clamps. A caulk gun is good if you want to seal it up better, and a hot glue gun will help if you are going to add an additional layer of screening. That's it! Do share if you try this project, and tell what you think. Additional plans for making these devices are elsewhere on the net, and may obviate the need for the hard to find tapstock. Good luck!