How To Connect Two Rain Barrels In Series

Many of you, whether you’re using one lone rain barrel or a gigantic poly tank, have come to the stage where the amount of available rainwater has exceeded your storage capacity.

If this is the case, it might be time to buy an additional rain barrel or storage container. There are several methods that are useful for connecting two rain barrels in series in order to double the amount of rainwater collected.

These instructions are for traditional 55 gallon rain barrels, plus a few other parts (like a used hose) that can be easily obtained.

  1. Level and clear a space that is large enough for two 55 gallon rain barrels to be placed side by side underneath your downspout
  2. Stack either cinder blocks or bricks to create a pad large enough to fit two barrels. One should be on the ground and the other pad should be raised about 6-8 inches
  3. Put rain barrel number 1 on the raised pad, directly underneath your drain spout. Put rain barrel number 2 on the pad that’s at ground level
  4. Time for the used hose. Cut a length of hose sufficient to stretch from the first barrel’s overflow on top over to the second barrel’s top filling hole. Take the hose’s threaded end and screw it onto the barrel’s overflow fitting
  5. Put the unthreaded end of the hose directly into the second barrel’s top opening and voila! Now when rain has filled up your first rain barrel, any surplus water will flow directly through the hose to your 2nd barrel

Here’s another set of instructions:

You will need:

  • 2 PVC rain barrels
  • 2 1/2 inch PVC pipe connectors (threaded smooth female end at one side and the threaded male end at the other side)
  • 1 length of 1/2″ PVC pipe
  • 1 female threaded extension connector
  • 1 female smooth right angle connector
  • a few bricks for elevation of the first barrel
  • an optional small size PVC cement container
  • tools required are an electric drill, a hacksaw, and a 13/16′ drill bit.
  1. Drill a hole close to the top of barrel #1 toward where barrel #2 will be located. Barrel #1 should be 3-4 inches above the top of barrel #2. Size of the drilled hole should be approximately 13/16 inches.
  2. Time to attach the connectors. Working from the inside thread the male threaded connector through the hole so that it touches the barrel wall. Working from the outside, you’ll need to thread your extension connector through your barrel. Tighten it by hand till it’s snug. Any water that flows through this overflow connection won’t be under pressure so it won’t leak much.
  3. Add the right angle connector and the extension pipe. Screw the male-threaded 2nd connector into your extension connector. Cut a long enough length from your 1/2″ PVC pipe long enough that it will reach directly over barrel #2’s filler hole. Then slide your right-angle connector onto your pipe, pointed downwards toward barrel #2’s opening.
  4. That’s it! Make sure that barrel #1’s larger lid hole is located directly beneath the downspout. In the event that not all the water enters the hole, it will simply pool on top of the lid and overflow eventually into the opening.

By connecting two rain barrels in series you will be capturing double the amount of rainwater – nice!

A decent sized rainfall can fill easily more than one barrel. A general rule is that a 1,000 square foot roof can collect approximately 600 gallons for every inch that falls!

During a good rain, your rain barrels could be filled in a matter of minutes.

Remember that rainwater does not contain any of the minerals that are in wells, or any of the chlorine that’s in municipal water supplies, so it’s perfect for watering your lawn and gardens.

Rain barrels can be used for augmenting normal watering. It will reduce your watering bill, plus it’s better for the grass.

There are some direct systems available that can pump the rainwater you’ve collected directly to designated draw-off points – I haven’t done this yet, but I think it would be a really nice setup.

Here is one that I found on YouTube that I am thinking about building out:

Two 55 gallon rain barrels, when full, will supply enough rainwater to sprinkle an average lawn for about 45 minutes.