Building the Perfect Rain Barrel System

Mike Hillman

Master Gardener

There’s nothing like a drought to raise one’s awareness of just how precious water really is. With water just a twist of a tap away, it’s easy to feel complacent while watching news footage of sun parched arid lands. But as we entered into our forth year of drought conditions last year in Georgia, with the heat index often in the high nineties, and with fields and lawns brittle and brown, it became harder and harder to ignore. For the past few years my wife depended upon me to keep our lawn and garden watered. Given my prior, less then stellar record with plants, I wanted to water aggressively , but was limited by my concern over the farm’s well. Unwilling to accept any limitations on my ability to water, I set off to research other sources of water. Since the beginning of recorded time, mankind has been using collections systems to gather and store rain water for future use, and while the appearance of the systems has changed, the basic elements that make them up have not.

All you need is a wide surface and a piping system to direct the water to the storage device. Roofs and down spouts fulfill the first two requirements and are at the disposal of every homeowner, it’s getting a proper water storage device that trips up most would be water collectors. Trash cans are almost everyone’s first choice. Readily available, that can be put into use with a minimal amount of effort or cost. However, lacking a proper drain, they can only be emptied by having their owner’s bend over and scoop the water out – a task which loses its luster after a few days. Not to mention the fact that the few unretrievable inches at the bottom of ‘emptied’ trash cans forms the perfect misquote breading grounds….On the opposite end of the spectrum, there are many manufactured rain barrel systems on the market to chose from, ranging in price from $85 to $135 a barrel. Considering a single 55 gallon rain barrel hold only enough water to maintain a four by ten foot garden for, at most a week, manufactured systems are a bit pricey. For gardeners willing to put in a little sweat equity, there is a third path which will allow you to capture and store as much rain water as you want while leaving your wallet virtually unscathed.

 The first thing you need to do is identify a source of food quality 55 gallon barrels. Manufacturers of fruit and soft drink products are an excellent source. And since in most cases the barrels are only allowed to be used once, manufactures are happy to see you cart off as many barrels as you can for free, or at most, at a minimal cost of a few dollars. (Manufacturers have to dispose of barrels as hazardous waste as they are made of plastic, which is costly to them). Most ‘do-it-yourself’ rain barrel instructions recommend you get barrels with removable tops for two reasons: so you access the inside of the barrel to fasten your drain fittings; and, to allow you to clean out any leaves that enter the barrel. I however, recommend you look for sealed barrels for three reasons. First, they are more plentiful; second, as you’ll soon learn, a plumber’s pipe tap will allow you to fit a drain fitting without having to get inside the barrel; and third, instead of worrying about cleaning out the barrel – a simple down spout gutter screen will be more then adequate to keep any leaves out of your barrel. A word to the wise here … don’t skimp on the number of barrels you bring home. I have more then 18 barrels scattered around my house holding 1900 gallons of water – and my master gardener wife goes through them in three days just with regular watering of her multiple gardens. Whether you have adequate locations for your barrels will affect how many barrels you need. In selecting barrel placement, make sure you take the time to look at the vegetation in the area. The chances are better the even that over the years the area has attracted water loving plants that will not look kindly on having their water supply cut off. If you want to keep those plants, you might want to put in fewer barrels than planned, thereby assuring that they get some runoff.

 OK, now let’s get to building your perfect rain collection and storage system … The first thing you need to do is turn the barrels over and using a 1 inch hole saw, or paddle drill bit, cut a single hole in the bottom of each barrel – preferably near the edge. Next, contact your favorite plumber and ask if he has a 1 inch pipe thread and would mind cutting a few ‘threads’ in a rain barrel for you. Since it only takes 30 seconds a barrel, if you’re a good customer, most plumbers will do it for free, epically if you take the barrels over to their shop. [Note: If you can’t find a plumber with the 1″ pipe tape, if you’re local (in the upper middle Maryland, middle lower Penna. area) drop me a line atmichael@emmitsburg.net. I’ll send you mine, all I ask is you send it back!

Next find a high quality paint primer that will stick to plastic, and then paint them the color of your choice (in my case, I chose white). Believe me, while having a ready source of water will make your gardener spouse happy, not having them stick out like a sore thumb and take away from the beauty of their garden will make them even happier, not to mention your neighbors.If your going to build a four barrel system, use a 2×8 for the horizontal support. A good rule of thumb is to add 2″ to the ‘width’ of the horizontal support for every 2 barrels you add. For example, my eight barrel system uses a 2×12 for its horizontal support (with two extra vertical supports in the center.) Make sure your dig far enough down so the ends of the post site on ‘solid’ ground, and then cement them in. I recommend building your stands first, then ‘sinking’ them into the ground – that way you can be sure the stand will be level.

While the paint is drying, head down to your local hardware store and pick up the following PVC parts you’ll need to connect your rain barrels:[Note with exceptions noted by ‘*’, all PVC components are per/barrel. So if you are building a four barrel system, get four of each of the components listed below]½ PVC parts (Used for the overflow vent)1 – Male Threaded Connector2 – 90Elbows4′ of pipe 1″ PVC parts:1 – Male Threaded Connector1 – 90 Elbow 1 – 3-Way ‘T’1 – Ball Valve (threaded) (*per barrel system)3′ Pipe3″ PVC parts (*per barrel system)2 – 45 Elbows3′ of pipe1 Down Spout to Drain Pipe Connector

Other supplies:• Clear PVC Glue• Pack of 100 Grit Sandpaper• Tube of Silicone Glue• 1″ Brass Hose Connecter

 Once the plumber has cut the ‘female’ threads into the barrel, coat the threads of the male connecter with silicone, and using your hand, screw it in as tight as you can. Be careful! Don’t over tighten it or you might strip the treads of the barrel. Once set, the silicone will form a waterproof seal. Next set the barrel in their place. If you’re installing more then one barrel in a given location, connect them all together by cutting your 1″ PVC pipe into lengths equivalent to the width of the barrel plus 2 inches. Using the ‘T’ connection, connect the top of the ‘T’ to the barrel connector. The two remaining openings of the ‘T’ connect to the ‘Ts’ of adjoining barrels. ‘T’s allow you to connect an unlimited number of barrels together, only space limits the number of barrels you can connect. Make sure you use plenty of PVC glue when making the connections – and make sure the full surface area has glueon it by giving the parts a quick twist! [Note: I’m from the old school, and used to always sand the ends of my PVC pipes before gluing them. But today’s building code expressly prohibits the practice of sanding the fittings first. Building codes require use of a primer (usually purple for PVC) before application of PVC glue. The reason is that testing by professional societies and testing institutes has found that the scuffs from sandpaper can actually line up just right and cause a path that the cement cannot fill and be a path for water to leak. This usually only results when people don’t do the proper quarter twist when assembling the parts. For the purposes of rain barrels, it’s ‘six of one, half a dozen of the other’ to say that purple primer is absolutely necessary verses sanding and no primer – but it’s always good to use building code practices, and given it doesn’t cost you anymore to meet the code, I encourage you to do so!] 

For your drain, tap into the common pipe somewhere in the middle (this way you drain all barrels equally) using another ‘T’ connector. Cut and install an appropriate length of pipe to allow the valve to protrude a comfortable distance from the bottom of the barrels. Connect the Ball valve to this pipe and then connect the brass hose fittings to the value. (If your only hooking up a single barrel, connect the drain pipe and ball valve directly to the threaded male connector attached to the bottom of the barrel.) With your barrel drain system now in place, it’s time to hook them up to the down spout. Cut a six to eight inch length of three inch pipe and stick in into one of the vent/fill holes at the top of the barrel. (Be careful when selecting which hole to insert the pipe in. Most barrels have two different threaded vent caps. One cap is solid, the other has a threaded center hole in it that can be ‘punched out’ and fitted with a ½ PVC tap for use in directing the overflow. So if you can, place the pipe into the hole sealed by the solid cap.

If the pipe doesn’t slide into the hole, use a rasp to widen the hole. Cut another piece of three inch pipe of sufficient length to reach the down spot. Where the pipe meets the down spot, cut the down sport and install the down spout – drain pipe connector. Connect the other 45-degree elbow to the drain pipe connecter and then connect the pipe to the barrel. (The 1 inch drain pipe connecting the bottom of the barrels will serve to distribute the rain water to all the barrels, so you only need one connector to the down spot.) Before you put your ladder away, make sure you install the down spout screen.

 If your looking to ‘wow’ your neighbors or just maximize water pressure coming from the barrels, I strongly recommend you place your barrels on an elevated stand, which can easily be built using a few pressure treated4x4’s and 2×6’s. Elevated barrels also don’t take up precious grading space and do form nice spots for shade loving plants. Lastly, to help you want keep an eye on the water level in the barrels, a water level indicator can easily be made using simple clear tygon tubing. Connect one end to a fitting taped into the bottom of one barrel. Secure the other to end of the tube to the top of the barrel using tape. The water in the tygon tube will equalize with that in the barrel giving you an accurate reading. There you have it! Now all you have to do is sit back and wait for rain. A three-hour light rain filled our 18 barrels to overflowing. How quick your barrels fill depends upon how large the collection surface you use. While this might seem like a lot of work, if you do everything in a production like fashion, and you get all your parts in advance, it only takes an hour to assemble everything and install a barrel. As for your cost, excluding paint, each completely outfitted barrel will run you about 15 dollars. Far cheaper then any manufactured system. Of course the difference between the manufactured system and the system described here is you do all the work in building it! While you’re waiting for the paint to dry, build the stands for the barrels. A simple two barrel system like the one in the photo to the right only requires two 4x4x8 pressure treated posts and three 2x6x8 pressure boards.If your going to build a four barrel system, use a 2×8 for the horizontal support. A good rule of thumb is to add 2″ to the ‘width’ of the horizontal support for every 2 barrels you add. 

For example, my eight barrel system uses a 2×12 for its horizontal support (with two extra vertical supports in the center.) Make sure your dig far enough down so the ends of the post site on ‘solid’ ground, and then cement them in. I recommend building your stands first, then ‘sinking’ them into the ground – that way you can be sure the stand will be level. While the paint is drying, head down to your local hardware store and pick up the following PVC parts you’ll need to connect your rain barrels:[Note with exceptions noted by ‘*’, all PVC components are per/barrel. So if you are building a four barrel system, get four of each of the components listed below]½ PVC parts (Used for the overflow vent)1 – Male Threaded Connector2 – 90 Elbows4′ of pipe1″ PVC parts:1 – Male Threaded Connector1 – 90 Elbow1 – 3-Way ‘T’1 – Ball Valve (threaded) (*per barrel system)3′ Pipe3″ PVC parts (*per barrel system)2 – 45 Elbows3′ of pipe1 Down Spout to Drain Pipe ConnectorOther supplies:Clear PVC GluePack of 100 Grit SandpaperTube of Silicone Glue1″ Brass Hose Connecter

Once the plumber has cut the ‘female’ threads into the barrel, coat the threads of the male connecter with silicone, and using your hand, screw it in as tight as you can. Be careful! Don’t over tighten it or you might strip the treads of the barrel. Once set, the silicone will form a waterproof seal. Next set the barrel in their place. If you’re installing more then one barrel in a given location, connect them all together by cutting your 1″ PVC pipe into lengths equivalent to the width of the barrel plus 2 inches. Using the ‘T’ connection, connect the top of the ‘T’ to the barrel connector. The two remaining openings of the ‘T’ connect to the ‘Ts’ of adjoining barrels. ‘T’s allow you to connect an unlimited number of barrels together, only space limits the number of barrels you can connect. Make sure you use plenty of PVC glue when making the connections – and make sure the full surface area has glue on it by giving the parts a quick twist![Note: I’m from the old school, and used to always sand the ends of my PVC pipes before gluing them. But today’s building code expressly prohibits the practice of sanding the fittings first. Building codes require use of a primer (usually purple for PVC) before application of PVC glue. The reason is that testing by professional societies and testing institutes has found that the scuffs from sandpaper can actually line up just right and cause a path that the cement cannot fill and be a path for water to leak. This usually only results when people don’t do the proper quarter twist when assembling the parts. For the purposes of rain barrels, it’s ‘six of one, half a dozen of the other’ to say that purple primer is absolutely necessary verses sanding and no primer – but it’s always good to use building code practices, and given it doesn’t cost you anymore to meet the code, I encourage you to do so!]

For your drain, tap into the common pipe somewhere in the middle (this way you drain all barrels equally) using another ‘T’ connector. Cut and install an appropriate length of pipe to allow the valve to protrude a comfortable distance from the bottom of the barrels. Connect the Ball valve to this pipe and then connect the brass hose fittings to the value. (If your only hooking up a single barrel, connect the drain pipe and ball valve directly to the threaded male connector attached to the bottom of the barrel.) With your barrel drain system now in place, it’s time to hook them up to the down spout. Cut a six to eight inch length of three inch pipe and stick in into one of the vent/fill holes at the top of the barrel. (Be careful when selecting which hole to insert the pipe in. Most barrels have two different threaded vent caps. One cap is solid, the other has a threaded center hole in it that can be ‘punched out’ and fitted with a ½ PVC tap for use in directing the overflow. So if your can, place the pipe into the hole sealed by the solid cap.) If the pipe doesn’t slide into the hole, use a rasp to widen the hole. Cut another piece of three inch pipe of sufficient length to reach the down spot. Where the pipe meets the down spot, cut the down sport and installthe down spout – drain pipe connector. Connect the other 45-degree elbow to the drain pipe connecter and then connect the pipe to the barrel. The 1 inch drain pipe connecting the bottom of the barrels will serve to distribute the rain water to all the barrels, so you only need one connector to the down spot.) Before you put your ladder away, make sure you install the down spout screen.

 If your looking to ‘wow’ your neighbors or just maximize water pressure coming from thebarrels, I strongly recommend you place your barrels on an elevated stand, which caneasily be built using a few pressure treated 4×4’s and 2×6’s.Elevated barrels also don’ttake up precious grading space and do form nice spots for shade loving plants.Lastly, to help you want keep an eye on the water level in the barrels, a water levelindicator can easily be made using simple clear tygon tubing. Connect one end to a fittingtaped into the bottom of one barrel. Secure the other to end of the tube to the top of thebarrel using tape. The water in the tygon tube will equalize with that in the barrel givingyou an accurate reading.There you have it! Now all you have to do is sit back and wait for rain.A three-hour lightrain filled our 18 barrels to overflowing. How quick your barrels fill depends upon howlarge the collection surface you use.While this might seem like a lot of work, if you do everything in a production like fashion,and you get all your parts in advance, it only takes an hour to assemble everything andinstall a barrel.

As for your cost, excluding paint, each completely outfitted barrel will run you about 15dollars. Far cheaper then any manufactured system. Of course the difference betweenthe manufactured system and the system described here is you do all the work inbuilding it!

Read other articles on gardening in drought conditions

Read other articles by Michael Hillman