Adventures of a Transplanted Gardener

Single rain barrel near vegetable garden. Photo by Stibolt.
Closed rain barrel
system with no outflow.

Rain barrel diverter details
by Ginny Stibolt

This page is the supplement to this article: Rain Barrels Revisited.  

The diverter described here was constructed for our closed barrel system shown in the photo to the right. If it's raining too hard, or if the barrel fills up, the water overflows into the through pipe set into the bottom of the catch basin and continues down the downspout. 

My husband fashioned the diverter from a plastic storage container and standard PVC plumbing parts purchased from Home Depot. Here are the instructions:

Cut a gap in the downspout an inch or two smaller than the height of the catch basin. Photo by Stibolt.

1) Cut a gap in the downspout that is an inch or two shorter than the height of the catch basin.  The catch basin will rest on the bottom part of the downspout, so you'll need to support the bottom section of the downspout by fastening it to the building.
2) We used 2.5-inch diameter PVC coupling for the overflow pipe. The coupling consists of an inner sleeve is a bushing and outer sleeve is an unthreaded straight-through union fitting. The two pieces connect at the bottom of the catch basin. Cut a hole in the bottom of the catch basin to be a tight fit for the inner sleeve.  Also use a 1/16-inch drill bit to drill two weep holes so when the rain stops the extra water can slowly drip out when the barrel is full.
3) We used a series of 3/4-inch PVC pipes and elbows for diverting rainwater to the barrel. At the bottom of one side of the catch basin, we cut a hole to match the 3/4-inch pipe. Again, you will need a bushing on the inside of the catch basin so the pipe doesn't slip out.  
All the parts for a rain barrel diverter. Photo by Stibolt
Place the smaller coupling on the side first. Photo by Stibolt.

All of the pieces laid out in order. All these parts are held together with friction. This way they can be disassembled for cleaning and to outfit a new catch basin when the plastic becomes brittle.

Insert the 3/4-inch bushing and straight-through union fitting on the side of the catch basin first.    
The through pipe is a coupling that is connected at the bottom of the catch basin. Photo by Stibolt.

The inner and outer sleeve of the 2.5-inch coupling meet at the bottom of the catch basin. (Above, the bushing which serves as the inner sleeve is being inserted. The straight-through union fitting is held in his left hand.) Cut the hole in the bottom of the catch basin with a jig saw so that it is slightly smaller than the inner sleeve of the bushing. Use sandpaper to size the hole so there is enough friction to hold the pipe in place. (Otherwise it will fall into the downspout during the first heavy rain.)

Tip the diverter in place.  The bushing extending from the bottom of the catch basin keeps it from sliding off the downspout. 

The standard fitting included with industrial barrels for a pumping device. Photo by Stibolt.

The threaded fitting is standard for the industrial barrels--it's used for a pump. The standard 3/4-inch threaded plumbing fixture fits perfectly. 

The last step is to insert the horizontal pipe from the diverter to the elbow.

Completed diverter system on a single rain barrel. Photo by Stibolt.

Here are all the pieces are in place. There are no vents in the barrel so as the water flows in there will be gurgling as the air comes out of the barrel. When the barrel fills up, the water rises in the pipes and into the catch basin. The water level rises above the through pipe in the center and overflows into the downspout.  

The weep holes in the bottom of the catch basin allow the water to slowly drip out once the rain stops so you don't attract mosquitoes. 

This detailed description is of our system. Your situation may require a different arrangement and different fittings.   

Back to the Rain barrels revisited article.

Ginny Stibolt is a life-long gardener, a botanist, a naturalist, and a garden writer. You may contact her or read more of her articles posted on her website: www.greengardeningmatters.com.

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Adventures of a Transplanted Gardener