How To: Build a Low-Cost Rain Barrel

So maybe you've read my How To on rainwater collection, and you're ready to give this a go. I know several people who have gotten to this point and stopped. They got the raw barrels, and for whatever reason, they just didn't finish. They've been setting there for years - unused. Time and priorities are always an issue, but there's no excuse for letting this one slip through the cracks. This job is about 2 hammers out of 5 on difficulty (but only because we are using power tools, otherwise it would be a 1), and about 1.5 dollar signs out of 5 (the cost of the barrels is variable, but the rest is quite cheap). Really, the barrel can be painted over a weekend of intermittent activity, and the rest of the work can be done in one evening. It's really not hard.

**NOTE** My How To is for non-potable use. There are ways to adapt this simple system for potability, but that lies outside of my relm of expertise.

We'll start with the tools list. It's not terribly long or complex. When I built my barrels, the only thing I had to buy was the 1" hole saw for the drill. If you are lacking in power tools, I wouldn't buy them just for this project. Try to borrow some if you can.

Tools needed:

  • Drill with 1" hole saw
  • Sawz-all, saber saw, or jig saw with a fine or all-purpose blade
  • sharpie
  • scissors
  • makeshift compass (I used a screwdriver and some butcher's twine)
  • plot of hole pattern
  • tape measure
  • spirit level
Now the materials. Other than the barrels, everything on the list can be found at your local home improvement mega-center. We discussed some ideas for getting the barrels in the previous article. Of the 6 that we made, 2 came from a garage sale, one from craigslist, and 3 from a neighbor. All had been acquired with the intent of making rain barrels, but stalled out at that point. Of the 3 that we purchased, we paid around $5-10 each. The ballast need not be anything fancy. This is simply to help hold the barrel in place when there is little to no water inside.

Materials list (minimum for one barrel):
  • 1 uncut heavy-duty plastic 55-gallon barrel [cost variable]
  • fiberglass window screening [about $3 per barrel, comes in rolls]
  • (2) 2' bungees with hooks [$1 each]
  • 3/4" brass spigot [$7]
  • outdoor caulking [$3, but I'll bet you already have some]**
  • flexible gutter extension [$3]
  • zip-ties [$2]**
  • 3/4" P-trap [$3]
  • rocks/bricks/ballast [free, look around the yard]**
  • cinder blocks [$1 each]
  • paint and primer [use whatever is handy]**
  • brushes and rollers [ditto]**
  • sandpaper [use what you have]**
The items with ** are ones that I had on hand. ~$22 + the cost of the barrel, which you might be able to get for free. (Go ask!)

Step 1: Plan
Choose the location(s) for your rain barrels. Maybe you want yours hidden from view or proudly displayed. Your call. Likely, you'll want them to be within a foot or two of your downspouts. Otherwise you'll have to pipe the water to the barrel. Not impossible, but something to consider. Also consider how you will use the water. If the barrel(s) need to be elevated - 3 inches or 3 feet - you'll want to plan for that. At peak capacity, we had utilized 3 of our 4 downspouts with 1, 2, and 3 barrels at those locations. We opted for extra capacity in our back yard as it was easier to hide (stupid subdivision covenances), and that is where we needed the water.

***Disclaimer*** Steps 2 through 6 are only for the barrel under the downspout. If you are daisy chaining, those will follow a different method. See Step 7 below.

Step 2: The Inlet
The whole point of the barrel is to get water into it. The method we chose (the pie-wedges) was suggested by one family who sold us some barrels. It involves cutting pie-wedge shaped openings in the top and then covering it with window screening. These openings may seem like overkill, but stay with me. I'm going to take a wild stab and guess that there is more than water coming down your downspouts. Leaves, tree pollen, shingle gravel, small woodland creatures. You don't want these in the barrel. You'll need a 'filter' of some sort. With this method, the water will come down your downspout and spill out onto the screening. The water will filter through whatever area is not blocked by roof debris, thus all the openings. After a rain, you'll clearly be able to see the debris and clear it simply by brushing it off.

These large openings also act as a vent to let the air out as it is replaced with water. I don't care what anyone says, large or small water tanks, venting MUST be addressed. It is a fact of life and physics. You may have a different water inlet method, and that is fine, just be sure that you have an exiting air vent or you will have problems.

The pie-wedges are not something you'll want to just 'wing it' on. The last thing you want is for this to break and end up with a big gaping hole in your barrel. The webbing that remains between the openings will support the screening on top as well as help maintain the structural rigidity of the barrel. I took the time to layout a hole pattern for the wedges, with one 1-inch hole at each corner. This file is available for download at the end of the article and on the right side under "NtJS Downloads". Once plotted, I poke a hole at each point and place the plot on top of the barrel. I use the sharpie to mark a dot at each location, 18 in total. Now comes the drill and 1" hole saw. Be forewarned - the plastic can be upwards of 3/8" thick on the top. You may go through a couple of batteries just getting through the holes for one barrel. have your charger handy. A corded drill may work better here. **Note: the barrels are not terribly heavy when empty and have low friction. You may need a friend to steady the barrel or find a way to secure it while you drill and cut. I used bungee cords to hold it against a bench on the deck.

Next you'll need the power saw to 'connect the dots'. Start on the outside edge and go 'tangent to tangent' for a clean final appearance. You may want to draw some guides with the sharpie and a straight edge. I used the makeshift compass and sharpie to draw the arc between the outer most holes as I wanted that cut to be concentric with the lip of the barrel. But thats just me, you could skip that. Take your time with this part. This is the easiest part to screw up. If all goes well, you'll have something like what is in the picture.

Step 3: The Outlet
There is a bit of planning needed here - measure twice, cut once sorta thing. We were using our barrels mainly to fill watering cans, occasionally 2-gallon buckets. Based on that and our plan from Step 1, we chose a height to drill our outlet hole. The other edge to that sword is that the higher you go up on the barrel, the less easily accessible capacity you have. Any water below that level will require tipping the barrel.

The beauty of this step is that a 3/4" fitting will screw directly into the hole made by a 1" hole saw. Once drilled you may do a dry fit first, but when you are ready to put the spigot on for good, smear a little silicone caulking on the threads and turn it into the hole. Just be sure to get it tight to the barrel and pointing the right direction (down). Don't strip it - you have one shot at this. We'll finish sealing it with caulking after the paint is dry.

Step 4: The Overflow
We've tried a few methods on this one and my best suggestion is to install a small P-trap like what is under your sink. With water in the 'P', mosquitoes can't get in to lay eggs, yet water can freely over flow out. Once again, you'll be using your 1" hole saw and treading the assembly into the hole. Location is at your discretion. One tip is that some folks like to put a hose connection on the outside of the overflow so that they can hook a soaker hose onto it and run it through the landscaping so not to waste the overflow and end up with a small pit next to the barrel.

You may think, "with such large openings in the top, who needs an overflow?" That's what I said. After trying to do without, and letting the water overflow out the top, I found that the water was pushing the screening up and causing gaps that let mosquitoes in. This was my best solution. Maybe you have a better one? Let us know.

Step 5: Paint

Even if your barrels are opaque, you may not want to skip this step. Our bright blue barrels were great at stopping algae growth, but otherwise an eyesore considering their surroundings. Our chocolate brown paint job was great for making these guys mostly disappear into the landscape. Materials can vary, but likely any barrel suitable for this application will be made of HDPE or PP. This is great for durability and cleaning. Not so great for paint. Results may vary. I scarred ours up with 60 grit sandpaper before priming them. Once cured, I applied the color coats. Use as many as are needed to get a consistent opaque color. This step is done last in an attempt to minimize scrapes and scars from processing.

My best advice here is to paint the sides first. This way you can hold onto the top to steady the barrel. Once that is done, then paint the top. Give your paint time to cure before adding successive coats. We used regular house paint. Spray paint didn't seem to be a good fit to us as you'll go through several cans on one barrel. If you have a friend with access to a paint booth, then it may be a good time to cash in a favor. Alternatively, if you have kids, they may want to help. Put on the paint smocks and let them have at it. Just be sure to smooth out the paint as they go.

Step 6: The Install
You're almost there. Once the paint is dry, cut a piece of the window screening and cover the top, wrapping the excess to the sides. Use the bungees to secure it in place by wrapping them around the screening. Use the scissors to trim off the excess.

Use some silicone to seal around your spigot and overflow. While that is drying, remove your aluminum downspouts and replace them with the flexible gutter extensions. These will allow you to lengthen and shorten as needed. Even go around corners, which is pretty handy. I used the zip ties to hold the end of the extension to the barrel by looping them through the bungees. I do not recommend having aluminum downspout contacting your screen as you see here. It is much more likely to wear a hole in the screen letting in, you guessed it, mosquitoes.

Prep the site, place your cinder blocks, and check for level. Once you are ready, set the barrel in place and load the ballast. Check the level of the barrel now. Trust me, now is the time to get this right. Attach the downspout, and pray for rain.

Oh! be sure that the spigot is turned OFF. Small detail.

Step 7: Daisy-chaining
This is a very simple way to add capacity to the single barrel system that we built above. These are even easier to make.

Materials list (for daisy chaining multiple barrels onto one down spout)
  • 1 uncut heavy-duty plastic 55-gallon barrel [cost variable]
  • a few feet of garden hose [cheap at garage sales]
  • male-end hose repair kits (2 per daisy chain) [$2 each]
Step 7b: Layout
Carefully plan the location as in Step 1. They should be close together, but not touching. If they were then they may rub together and you'll lose your paint. Be sure that you have plenty of room and can build up any foundation that is needed. Set the barrels in place and make a preliminary mark for the inlets/outlets that we'll talk about next.

Step 7c: In/Out
The daisy-chained barrels use the same opening for the inlet as the outlet. There are various methodologies on this, but I chose this one for a few good reasons. First, I used garden hose as it is flexible and will stand up to the elements. Second, I wanted to do this as minimally as possible, so complex PVC structures were not happening. Last, by mounting the inlet/outlet low, all the barrels will have the same amount of water in them for holding them in place. Besides, if I mounted it high - where the overflow is - then I would need a spigot for each.

The hose repair kits consist of a treaded end (to thread into the barrel), a smaller end (that goes into the hose), and a clamp. We'll attach the clamp and hose later. Do what comes natural with the rest.

Step 7d: Vent
We've already discussed the need for vents, but on the daisy chain barrels, we don't have the large openings like we do on the main barrel. Fear not. Here are two ways to get plenty of ventilation. Either of these should be completed post-paint, put planned for and prepped now.

The first and easiest is made possible by the bung on top of the barrel. Ok, Beavis, I said bung. All of the barrels I had found had one or two threaded caps on the top - 3-4" in diameter. To use these, I simply unscrewed the cap, covered the top with window screening, and secured it with zip ties. Ta-Daaaaaa.

The second way was what I had to do with one barrel that already had a hole cut into the top. This time, I left the bung in place. I sized up a piece of window screening that would cover the hole and overlap the plastic by an inch or two. I ran a bead of silicone caulk around the hole, and pressed the window screening into it. Not too shabby, but a tad ghetto. Method 1 is much cleaner.

Step 7e: Paint
Same as Step 5 above.

Step 7f: Install
Mostly the same as Step 6 above. Be sure that these barrels are at the same height as the main barrel. To install these, you'll want to prep the sites and set the barrels in place as you had them before when we were marking for the inlets/outlets. Attach the garden hose and be sure there are no kinks. If there are kinks in the line, then you have too much hose. Trim a little and refit.

Other Options
If you are wanting more pressure out of your tanks, then I have one word for you: elevation. I was quite close to building an elevated platform for out 3 daisy-chained barrels just prior to selling them and moving. My best advice here is to over-build it. Over-engineer it. Remember how heavy these get when full? 8.33 lbs/gal x 55 gal/barrel x 3 barrels = 1374lbs!!!

If you are just dying to wash your car or run a lawn sprinkler off of these, then good luck. I wish you all the best. I've seen systems with pumps, pressure tanks, even one with plumbed spigots around the yard. This can be just as complex as you want it to be, but my guidance ends here.

My Hole Pattern
This is the pattern I used to layout the holes on top of the barrels. Pretty simple to use, but you will need a large format printer to plot it out. If you don't have access to one, or don't have access to someone who has access to one, then Kinko's is a good last resort. For full 1:1 scale, print the file at 24x36". I thought long and hard about charging for this file. In the spirit of eco-friendliness, this one is FREE. Download it here.

Somewhat Useful links
Pollution Prevention Factsheet
City of Austin Rainwater Harvesting Programs
The tutorial that got me started

***UPDATE*** Like our rain barrels? Let others know with a stylish and informative bumper sticker, coffee mug, or wall clock. Available now in our Cafepress shop!

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Green Me said...

Wow. Those are really excellent directions! We live on the Colorado prairie and considering our lack of natural water, we should really have a rain barrel.

BTW this is the first time (but definitely not the last) that I've been to your blog. I love the photo of the Chevy (my Dad still has the same model and color -- I have very fond memories of riding in it as a kid). And, I also think Suze Orman is a shill, although truth be told I had to look up the definition of shill! Thanks for blogging and submitting this post to the Green It! Carnival.


(not) the Jet Set said...

Thanks for the kind words. I was always put-off by the lack of a good tutorial online (or atleast one the I could find). After living in an area that was very supportive of rainwater harvesting, I thought it would be good to share our expertise.

good to meet another member of the old chevrolet set.


Bryce said...

This is awesome. Thanks for the great instructions. I will be off to Home Depot soon.

Greener Pastures said...

This is great- We are planning on putting one in this year. I just have to figure out how to get 20 feet of gutter up onto my garage first. How are you at gutters?



PS I highlighted your article as a fav for the Money Hacks Carnival this week. Click on Greener Pastures if you'd like to see it.

(not) the Jet Set said...

We're really glad to see that people are finding this useful.

Unfortunately, we only know enough about gutters to leave them to the pros. The seemless kind are best as they are less prone to leaks. Be sure that your fascia is in good shape and well sealed. This may not be bad to do, but do your research first, and do it right the first time. We've had leaky gutters before and they can cause BIG problems.

the undomesticated wife said...

Love this! We made a rain barrel a year or so ago and ever since, I've not had to pay to water any of my potted plants! It's great!

Beachbrights said...

I love this! Thanks for the in-depth explanation and pictures.

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