Making Rain Barrels Using Metal Trash Cans Instead of Plastic!

Metal rain barrels for a friend started out as a simple discussion about the pros and cons of each type of available barrel material. Here is the story of my friends rain barrel dilemma.

She has two large vegetable gardens and some very nice flowers and shrubbery. It takes a lot of water to keep all of this greenery going. Ordinarily this would not really be a problem except that she has very slow recovery from her house water well. So she asked me for some help designing and building a water capturing rain barrel system that would help her to keep these gardens alive when the weather is hot and dry. As with most rain barrel projects the goal is to capture as much rain water from the roof of her outbuilding and the house for use in her gardens.

One of her main objectives is to keep the project costs low, so we have been searching around for used materials wherever we could get them. Turns out another friend had some gutters fall down under heavy ice load, and these are available for free, so they will work nicely for this rain barrel project.

Another concern my friend has is that plastic has been linked to all sorts of health issues and she has become quite convinced that there is a strong enough link to Alzheimer's Disease that we cannot use plastics in any part of this rain water recovery project. This makes sense since the water goes directly into the production of edible plants.

She came up with two 30 gallon galvanized metal trash cans that will be used on the gutters of the outbuilding, one on each side. What I have done to get them ready to be used is to get a 1/2" metal flange and a matching gasket, and using a tapered step bit in my "Firestorm" cordless drill I put five holes into the side of the barrel. The flow opening plus four smaller holes for the bolts that hold the flange onto the drum. I used a 1/2" spigot with a standard hose thread so that she can connect a 5/8" garden hose to these metal rain barrels.

Using zinc plated hardware and a brass faucet valve I made a drain fitting on the side of the barrels as low to the bottom as I could get. These protrude out the side so that the drums can be placed on a flat surface about 36 inches off the ground. This height will give the water between 1.5 and 2.0 pounds per square inches of pressure. The simple formula for figuring this out is that for every 2.31 feet of elevation your water sits at then you will have 1 psi. In order to increase the pressure to say 5 psi, you would have to raise your water tanks to 11.55 feet off the ground.

You need to keep the hose length to your garden as close as possible, and also have the least resistance to flow by using largest diameter hose as you can manage. A soaker hose is not usually a great idea because the low pressure condition can make it flow just enough to soak the first part of your garden but not much will reach the end of your hose. It may be best to use an open hose with a simple single stream spray head on the end. This way you will not waste too much of your water in between your plants.

The last thing to consider is to have the water come out of your storage using a small inexpensive electric pump. these can be battery operated using a 12 volt car or tractor battery that you recharge in between uses with a regular battery charger or with a simple solar panel made for keeping batteries charged. There are also many hand pumps available that can be used to spray the water into your garden in a stream or jet. most of these add cost and complexity, so I prefer the relaxing old school method of opening a valve on the end of a hose as I wander around the garden.

Now it is time to connect her downspouts to the top of our drum. This lid is not fixed to the barrel and since it lifts off easily it can her help when we go to clean it out a few times each season. The downspout needs to be diverted into the barrel, and then an overflow needs to exit the barrel as high up as possible. This should be similar in size to the downspout you are dropping into the drum top. There are a number of ways to connect a plastic drum, but with metal you are really kind of limited in terms of off the shelf fittings. You can end up forming your own from sheet metal and rivets. My design uses a metal downspout adapter that would normally be riveted into the bottom side at one end of the gutter and the downspout is attached to this. Here i am using one on the lid and another on the side of the drum. This side one is then connected to the runoff line that was connected to the downspout before the addition of the drum.

There are some that will install a special and costly diversion valve in a "Y" pipe but there really is no need to do this if you connect an overflow fitting off the side like I do. Next you need to mount the drum up on something strong enough to support the weight. These metal drums would hold 30 gallons full, and with a drain fitting they will only hold about 26.5, so that multiplied by the weight of water at 8.34 pounds per gallon, and we have to support up to 221 pounds of weight in each barrel. These will be placed on a plywood platform with 2x4 framing and the legs will be 4x4 posts set into cement blocks with "quickcrete" brand cement poured into them so that I will not need to dig a post hole. This feature makes the entire thing movable since it is not fixed.

A few words on bugs and debris, you will need to keep mosquito's from hatching in your rain water and the simplest thing is to put a fine screen in the overflow vent pipe. The only trouble here is that this may clog up over time with crud. The best thing to do is to drop in those "mosquito dunks" that they sell at your local farm and fleet, or large hardware store.

Always drain the barrels and hoses in the winter. Keep a spacer piece handy to allow you to reconnect the downspout once your watering and growing season is over. Even if you had a diversion system it is not wise to leave any water in your barrel since it could rupture when it freezes.

If you have any questions about this project then just drop me a message, and I will reply as quickly as I can.

Thank you for reading my articles here on AC-Yahoo!