Installation of a rain barrel is not a particularly complicated affair.  The actual steps involved and hardware required will vary to a small extent depending on your location and the rain barrel you choose. 

If you want to buy one, check out the large selection of rain barrels at Clean Air Gardening.

There are several different types of rain barrels made from recycled food barrels, varying in size, shape and color.

The rain barrel installed here is a 65 Gallon Rainbarrel USA rain barrel from Clean Air Gardening.

This rain barrel is the most simple to set up of the rain barrels I have worked with and very sturdily constructed.  

Once unwrapped, remove the lid simply by lifting it off and remove the bundle of parts from the bottom and lay them out.  In this case, the parts consist of:

1. Two hose fittings for the overflow pipe.
2. A brass spigot pre-wrapped with Teflon tape.
3. A mosquito screen.
4. Two short screws
5. Two long screws

Since the spigot has already had the Teflon tape applied (Teflon tape acts as a sealant to keep water from leaking past the threads), simply thread the spigot into the threaded hole in the bottom of the barrel by hand.  You can use a wrench if you need to once you get it started but it doesn’t need to be much tighter than you can get it by hand. 

The mounting receptacle for the spigot on this rain barrel is located all the way at the bottom of the barrel so that you will be able to get every last bit of water out; a good thing to be sure but this means that you will need to set the barrel on a raised surface such as concrete blocks.

Next you will need to insert the two fittings into the holes located around the top of the barrel.  These fittings are to attach hoses to the barrel so that if the barrel overflows you can divert the excess water away from your house.  Since these are primarily a failsafe no Teflon tape is really necessary on the threads; seepage during heavy rain is not significant.

Carefully insert the nylon fitting into the threaded receptacle taking care not to cross thread.  Again a wrench could be used if needed but it shouldn’t be necessary.

Once the barrel is in place attach an ordinary garden hose to each fitting and route the hoses away from the house into a flower bed.  If you live in an area where heavy rains are uncommon you could possibly get by without an overflow hose but if water is continuously routed near the foundation of the house damage could occur.

A word about safety:  This rain barrel has a large lid that is simply placed on top of the barrel like a garbage can lid.  A small child, or pet can easily drown in even a much smaller container of water and as children are curios and like to look down into such things having this lid on this barrel unsecured if you have small children, grandchildren and frequent guest who do is a tragedy waiting to happen.  The two long screws provided in the kit will allow you to secure the lid semi-permanently by driving the screw through the side of the lid into the flange of the barrel.  It’s an easy extra step and very self-explanatory; it won’t take but a few more minutes of your time and it will be worth the effort.

If you don’t have small children being able to simply open the lid and dip in a bucket, or clean the barrel is beneficial and the wide opening is one of my favorite features of this barrel. 

Finally, once the lid is in place simply drop in the mosquito screen.  The barrel comes with two short screws to attach this screen but a small amount of plumbers adhesive or caulk will do the job much easier and will hold in the screen securely.  This screen will lessen the risk of mosquitoes using your new rain barrel to make more mosquitoes and will also reduce the amount of debris that could fall into your barrel.

Since the entire wide lid of this barrel is basically a funnel it is a simple matter to set it under the drain pipe on a secure surface.  Remember that once filled this barrel will be extremely heavy and just because it is sitting level empty does not mean it will sit level on wet ground filled with water.  Bricks, or concrete blocks are really your best bet and will raise the spigot up off of the ground to make it easier to attach a hose or fill a container.

The  rain barrel will need to be located near a down spout from your rain gutter, if you want to get water from a downspout.

If you don't have downspouts, you can often still use a rain barrel. You just have to find one of those troughs where two parts of the roof come together and water pours out whenever it rains. Place the rain barrel under one of those spots, and you'll get plenty of water.

Generally, downspouts are attached to the house by straps and will need to be dissasembled.  Remove the screws holding the straps to the downspout and any screws that may have been put in to attach the spout to the gutter.  Once the brackets have been released the downspout can be removed and set aside.

When removing the screws and detatching the downspout, remember to wear safety glasses if you are using power equipment. We wouldn't want you to hurt yourself, would we?  

Now that the downspout is out of the way, we need to find a way to redirect water flow into the top of the rain barrel.  

There are several comercial products available for this purpose.

The Garden Water Saver downspout redirector is an excellent choice in that it attaches inline between joints of your spout and once your rain barrel is full water is automatically directed back out through the original spout.  It does require a small amount of cutting with tin snips in order to fit properly. Unfortunately, our downspout in this example is too large to use the Garden Watersaver.  

It is important that the concentrated water flow be directed away from the house or into the barrel as too much water in one place near the house could result in foundation damage.  Therefore it is unwise to simply let the water fall from gutter into the barrel for any significant distance.  For this particular installation the best solution was to use a plastic flex house available at most home improvement stores.  The flex hose can be secured using the existing straps and expanded and directed to the needed position. You can also find these flexible downspout redirectors online.

Your installed rain barrel should be placed on a reasonably stable and secure surface, like the wide concrete blocks in the picture above.  A barrel this size will weigh a substantial amount when full of water. Water weighs something like 8 pounds per gallon, so you can see how it adds up quickly!  

If you elect to use the lower mounting position for the spigot, be sure there is sufficient clearence for you to attach a hose in order to use the water you collect in the barrel.  The installation process is not particularly complicated as you just saw, but it does require some planning.