to see how I used PVC pipe to connect one barrel to the next in tandem. At the end of that tutorial I mentioned that I applied the lessons learned on the two barrel system I had at home to the three barrel system at the garden shed.
We put up a 12 foot gutter along the roof line at the back at the back of the shed and used a traditional downspout to send water directly down into the first barrel. We were lamenting the fact that we were only collecting half the water that was possible but were concerned about how we would get the water from a front gutter back to the same set of barrels. We definitely did not want to have barrels out front where they could be easily seen. After thinking about it for a while, we decided to use PVC pipe to solve the problem.
BTW, this very same shed is the target of another instructable where I showed how to install solar panels from Harbor Freight on it. You can see this at: https://www.instructables.com/id/How-to-mount-a-solar-panel/
Step 1: Materials Needed
All pipes and connectors are half inch here.
A gutter that ends in a flat end piece
A PVC connector that is threaded male on one end and non-threaded female on the other end
A PVC connector that is female threaded on both ends
A half-inch right-angle PVC connection that is threaded male on one end and non-threaded female on the other
Sufficient length of PVC pipe to reach on a slant to where the barrels are. If need to join two pipes together, you will need straight PVC connector that is female non-threaded on both ends
Two right angle PVC connectors that are female non-threaded on both ends
A piece of PVC to direct the water down to the opening of the barrel
Note: depending on the physical location of the front gutter and of the first barrel, you will need to get creative and make modifications in the parts needed.
Step 2: Constructing the Diversion
Insert the male threaded end of a PVC connector that has a non-threaded female end. The threaded end will stick outside the panel. To this connect a straight connector that is female threaded on both ends. Tighten this as much as you can. The hole should be just the right size to form a water-tight connection but you might want to caulk it. The water coming through it won't be under any pressure.
Now take a right angle connector that is male threaded on one end and female non-threaded on the other. Screw this connector onto the one coming through the end panel. You should be able to rotate the right-angled connector to the angle that points to above the top of the barrel at the back of the shed.
You now want to insert a long piece of PVC pipe that will lead back to the rear of the shed. I was able buy a 10 ft section but, despite the fact that the shed is 10 feet wide, it was not long enough because it was starting about a half foot in front of the shed and going back on an angle. We simply able to join the long pipe to a shorter one with a straight connector that is female non-threaded on both ends. This length of pipe will naturally sag, so you will have to support it in a few places along its length. We did this by partially screwing some 3 inch screws into the side of the shed in the right places.
Finally, you will have to make a right angle connection that will extend over the right place above the barrel and then another right angle connection that points down towards the barrel. I suggest that you not actually insert the down pipe into the barrel itself because you will be wanting to remove the lid to get water and to check the level. With these rain barrels it doesn't matter if the water coming down goes directly into the hole in the lid. The lip of the hole is lower than the outside rim of the lid. The water will overflow into the barrel first before it runs out of the lid.
We didn't glue any of the connections together because friction seems to hold everything in place and there isn't much water pressure.
You might want to choose 3/4th inch pipes and connectors if you have a much larger roof. This is adequate for what we have (120 square foot roof).