Introduction: Need Free Water? Build a Rain Barrel

Picture of Need Free Water?  Build a Rain Barrel

For the price of a 55 gallon plastic barrel (sometimes free), and about $10 in parts, you can build your own rainwater collection system. Water is good. Free water is better.

If you already know that water won't run uphill and how to handle a drill, you can do this. The most ingenious part of the design is the hose-to-barrel connection. Since the attached hose will frequently be tugged during normal use, it is important to use a mechanical connection rather than a glued connection.

This design uses a simple garden hose washer, standard garden hose parts, and a special adapter, that's not really all that special. It's expandable and useful for more than just capturing rain water.

Step 1: Got Parts?

Picture of Got Parts?

You will need a barrel. The bigger the better. 55 gallon is good. I like plastic, but metal will work. Don't use barrels that held something toxic in a former life, go for something wholesome, like lawn fertilizer, or laundry detergent. I picked up this one at a local recycler for $4.

Also, while in town, pick up a garden hose valve, garden hose washer, and a MHT to FPT 3/4" plastic adapter. What? MHT = Male Hose Thread. FPT = Female Pipe Thread. Plastic = plastic. You'll know it when you see it. Less than $10 total.

I had some old parts handy to draw from.

The gutter modification comes later.

Step 2: Tools Needed

Picture of Tools Needed

A drill. 1" drill bit. A Keyhole saw. That's all you need to modify the barrel.

To modify a gutter downspout, you will also need a heavy duty pair of scissors (or sheet metal snips), about 10 small sheet metal screws, and a small drill bit to pre-drill for the screws. A pop-rivetor would also work. The special pliers shown in the photo are for "shrinking" sheet metal. Optional.

Step 3: Saw an Opening in the Top of the Barrel

Picture of Saw an Opening in the Top of the Barrel

Just like in the photo. Unless you want to put the opening off-center. That may work better.

Step 4: Attach Garden Hose Valve

Picture of Attach Garden Hose Valve

Drill a 1" hole near the bottom of the barrel. The adapter and washer go on the inside of the barrel. The valve goes on the outside. The toughest part of this is that it requires someone with a really long arm to hold the adapter while someone else screws on the hose valve.

Step 5: Modify the Downspout

Picture of Modify the Downspout

Downspouts are easy to modify. Look at one closely, it will be apparent how they fit together. Use the small drill bit to drill out existing rivets if necessary. Some are put together with sheet metal screws. Just be flexible with your tools and mind, and you will be able to build a downspout to direct rainwater into your barrel.

The parts photo shows a flexible plastic downspout that may also work.

Step 6: Add More Barrels

Picture of Add More Barrels

I added a secondary barrel using a garden hose Y adapter as shown in the photo. I modified it later to replace the Y adapter with an additional dedicated hose to fill the secondary barrel. Putting your hose connections near the bottom of the barrel allows most of the water to be utilized from all barrels, even the secondary ones.

I learned that one 55 gallon barrel can fill up in about 10 minutes of heavy rain. The secondary barrel would only partially fill in that time due to the relatively small diameter of the garden hose. Adding two or three or more secondary barrels, each with its own dedicated fill hose from the main barrel, will work much better, saving more water during those times of heavy downpour.

Make your hose-barrel connections the same way for secondary barrels. The second photo shows a cut-away mock-up of the hose-barrel connection. In this case, a quick-release brass connector just happened to work for the inside job. However, the MHT to FPT adapter is better since it has a larger diameter. A different garden hose valve did duty for the outside job.

Step 7: Enjoy Free Water!

Picture of Enjoy Free Water!

Here's a photo of the rain barrel receiving its first deluge of rain water. There's a piece of window screen on the top of the barrel to filter out debris. The screen is also important in preventing mosquitos from entering and mulitplying.

As a bonus, this system makes a splendid watering system for gardens during dry seasons. I use tap water to fill the barrel with 15 or 20 gallons, and then use the barrel outlet hose to meter out water to specific garden areas. You can walk away from it, and your garden will slowly receive that 15 or 20 gallons, no more, no less. Very nice for those times when rain water is in short supply.


Stavros! (author)2015-01-11

To increase the flow of water out of the barrel use a 3/4" 1/4 turn ball valve instead of that hose valve. The ball valve has a much bigger diameter hole inside to allow water out that the hose valve.

KenM7 (author)Stavros!2015-05-08

That is a ¼ turn ball valve although the inside opening doesn't look like ¾".

Stavros! (author)KenM72015-05-09

1/4 turn ball valves come in several sizes, so that hole inside of that one is the same as a garden faucet. A 3/4" 1/4 turn ball valve will have a much larger hole inside, and still fit a garden hose. Check out the video on youtube called "Rain barrel water pressure/volume demonstration" to see the difference.

monica.tonty (author)2015-03-05

Did you use a 25ft hose to connect the two barrels? I'm trying to keep costs as low as possible.

SophiesFoodieFiles (author)2014-10-17

Waw, great idea!

Ploopy (author)2014-07-12


minnecrapolis (author)2014-01-31

You're not doing this for drinking water. From the comments, there are a lot of daft people looking at this instructable.

This is water that you will use for watering your garden/lawn.

Clearly common sense is no longer common.

Aquabarrel (author)2013-11-04

I'd suggest a large overflow port for places where heavy rains are common.

OR just use an inexpensive DIY kit like this one

Filtering on the downspout keeps the debris from matting down on the top screen material:

zilcho (author)2010-12-17

if your going to drink it i would add some water filters

groovy (author)zilcho2011-03-19

Bad choice of avatar........

kkarwan (author)groovy2012-04-10

and your name is great?

zilcho (author)groovy2011-03-20

How so?

bwells2 (author)2011-06-23

Do you know how much money it will save on your water bill? That is amazing! Thank you for sharing.

kkarwan (author)bwells22012-04-10

you should realy filter the water and boil it before ingesting as it can pick up tar bird manure, and solvents off f a roof not to mention the noxious chemicals that are in our atmosphere, that this water was recently in contact with.

jfellens (author)2011-07-28

We simply placed some feeder goldfish in our rain barrell to eat the mosquito larvae.

khalednm (author)2010-05-07

 has anyone looked into putting a deionizer into the spigot setup?  This would eliminate the risk of acid rain... and an activated charcoal filter should remove any other contaminants...

led_scorched (author)khalednm2011-07-15

The rain just ran over a roof.... I'd be more worried about what it picked up there (tar, solvents, bird poo, etc) than I would be about acid rain. This is meant for grey water type uses - drinking water is cheap enough (fractions of a cents a gallon) that I wouldn't recommend trying to pinch those pennies.

tastethefruit (author)2011-07-14

Very nice rain barrel - simple and easy. I have built something similar, but tie the barrels together. I use a small pump from Home Depot to empty the barrels.

You can see the beast here...

Also includes step by step instructions with pictures.

intel_intel (author)2011-06-13


greenlivingeco (author)2011-03-30

We just built our own rain barrel too. It is a little different from the one built in the post. Check out our step by step make a rain barrel guide to see how we built ours.

ezgnann (author)2011-01-18

I am having some trouble finding food grade barrels in my area (northern Louisiana). Is there any reason why 55 gallon plastic trashcans cannot be used? they are readily available, reasonable, and durable?

cytoxin (author)2010-07-31

Where did you get the parts for the hose connectors? I checked Home Depot and Lowes and couldn't find anything like these...

McSensei (author)cytoxin2010-08-02

Home Depot and Lowes _should_ have those parts. However, i found them at a local farm supply store, Rural King. With hindsight, I'd use larger-diameter hoses for the project. Garden hose is just too small to allow a significant amount of water to flow at "rain-barrel pressure".

jpatramirez (author)2010-06-27

what would someone recommend if you do not have a downspout? our pitched roof homes in El Paso TX do not normally have these there another way to collect water without downspout?

aptd27 (author)jpatramirez2010-07-09

@jpatramirez You would need a downspout diverter... you can get them here:

Rain Barrels

eddy14777 (author)2010-04-26

great thought but if you live somewhere with power plants basically in your back yard this could produce acid rain

becca-boo (author)eddy147772010-05-26

 Acid rain is fairly common, true, but the water that is being collected should only be used to water gardens, wash cars, etc.; every thing that would be exposed to the rain already. This water shouldn't be used as drinking water for sure, it's not exactly the definition of potable water.

Ryutso (author)2010-05-09

Or you flip the rain barrel over and have someone stand inside it and hold the 2 parts.

mclelm (author)2010-04-09

Rainwater Harvesting systems are great; I have two barrels in two locations.  I don't know if anyone mentioned this (I didn't read the 69 comments), but if you've got this type of white barrel or any other translucent barrel anywhere the sun shines on them, algae will grow; at least it did on my white barrel.  The barrel will have to be shielded in some way- by painting the barrel or some sort of solid box, trellis with vines, etc.

Greenehouse (author)2008-03-18

I wonder if there is any sort of filter (besides or in addition to) the screen that you could use that would filter out stuff off the roof you wouldn't want in your pool. (I'm thinking of using it to replenish evaporated pool water.)

McSensei (author)Greenehouse2008-03-19

I think using rainwater for pool water is a great idea. You would want to construct a better filter system though. I suggest a multi-stage system that begins with a piece of 1/4" hardware cloth, set up to be self-cleaning, and then, a piece of coarse window screen, and then a piece of fine window screen. I would look at drain/waste/vent 4" plastic pvc pipe parts and try to figure out something that would work. Probably a vertical arrangement with the screening installed at an angle, so that it is able to shed debris through an opening while allowing the water to fall straight through. You will just have to be creative. Finally, since most pools have their own filter systems, the final filtering and finishing could be achieved through standard pool chemistry and filter maintenance.

pkguy (author)McSensei2010-03-15

I would use it for the same things. I'm on the west side of Cleveland (Strongsville), where did you find your barrel for $4?

Goedjn (author)Greenehouse2008-06-13

USDA used to recommend a 10' sand-pipe. If you try to filter the water before it gets to the barrel, then you need a filter system with a large throughput. It works better if you have an initial catchment that can hold most of one storms worth of water, and then a sand-filled pipe to a covered cistern that holds your "filtered" water.

Skylerk (author)2010-02-18

There is an awesome rain barrel diverter called RainReserve. And it has a large spigot that can do up to 10GPM. And to modernmans question: the diverter and attachments are closed, so that water will go back up the tubing into the diverter and out the downspout. Found at:

!Andrew_Modder! (author)2007-08-16

ya, just collect it, strain it then purify or boil it! P.S. there is a company in texas selling bottled rain water, and they claim the mineral content makes the water taste almost a little sweet, and is defiantly difrent from your avrage water. I think im gona do this instructable, because where i live in Cuyahoga Falls, Ohio our water is bad (its really hard) and super calciumic (i made that word up so dont comment me on that word!)

lancesb (author)!Andrew_Modder!2010-01-16

I partly agree with with Dessyl, I've researched many of  the polluted rivers around the Great Lakes/ MidWest/ Northern Appalachia, & I wouldn't trust any tap water there either. But have you considered where you rain water comes from? You might want to do some research into acid rain, which was most prevelant around those same rivers & lakes. Texas (except for oil production metros like Houston), the SW, & the Rocky Mt states have purer rain water because it's evaporated from cleaner sources. I would say to anybody, if you don't like your tap water, do not drink you rainwater. & if you're using it for gardening maybe at least test the pH before you use it on expensive plants. Good luck.

Dessyl (author)!Andrew_Modder!2007-08-17

Yeah, I live in Stow, Ohio (which is right next to Cuyahoga Falls for those who don't know) and the water is pretty bad. But it isn't as bad as it used to be. At one point the the Cuyahoga River caught on fire near Cleveland due to the pollution (A long time ago). However, now the water just smells and tastes bad. This is a good idea. You can use the water for pretty much anything, but I have a few concerns. Because it is relatively stagnant water bacteria and algae can build up and mosquitoes may be attracted to it.

Goedjn (author)Dessyl2008-06-13

That's why people keep goldfish in their rain barrels. they eat the mosquito larvae.

Kiteman (author)!Andrew_Modder!2007-08-17

(There's a brand of processed cheese sold in the UK with the tag "It's calci-yummy")

amethysteria (author)Kiteman2007-09-26

We have a dairy-based dessert called "Calci-yum"

Down in wadsworth area, I was given a free barrel in may. I haven't had to turn on the garden hose once this summer. I was close back in july. I was just given 2 more barrels. I have one hooked up. Probably won't hook the other one up until spring. I might actually water the lawn next summer.

its like that all over northeast ohio. barbertons' is terrible at the irst of the month

bfarm (author)2008-10-09

What happens in Winter / freezing conditions? Can picture a frozen barrel with a massive run off of melting rooftop snow all pouring out next to the house's foundation. Maybe a much larger overflow? I'm thinking of using this set up connected to soaker hoses to water the landscaping.

McSensei (author)bfarm2008-10-09

In the winter, the barrel must be emptied of all water and snow-melt diverted away from the barrel. Not sure how well the collected rain water would work for a soaker hose. There is always debris in the rain water, and that may clog a soaker hose.

plumber4 (author)McSensei2009-09-20

The water works fine in the soaker hose. Not all of the water needs to be drained in the winter. When the water freezes, it must have enough room for expansion. If it doesn't the barrel may crack. Being that the walls of most barrels are so thick, I doubt that they would split. If you have metal fittings or piping, the water needs to be drained.

james.mcglashan (author)2009-08-12

what do u mean clean water there are no filters and the water has things from the gutter?????????

rowerwet (author)2009-06-28

to keep most of the junk out of my rain barrel, I cut my downspout about 7' above the ground, and put a PVC 3"X3"X2" hub on the end of downspout. the 2" is on the side at a 45 degree angle going down, coming off the lower 3" is a pipe that goes almost to the ground with a ball valve on the end. the two inch pipe slopes off to another 45 degree bend that dumps into the rain barrel bung (no cutting involved). I leave the ball valve shut and empty it out after each rain storm, this pipe captures the dirt and leaves that get washed out of the gutter, and after the pipe fills the rest of the water goes into the barrel. During the winter I leave the ball valve open and it drops directly into a grate that drains into under ground perforated pipe to carry the water away from my foundation, the over flow from the barrel goes to the same drain pipe. after all the water above the ball valve is emptied into the watering can, I siphon into the watering can from the other barrel bung with a "shaker" siphon (has a valve on the end with a marble in it to start the flow by rocking the hose in and out.

McSensei (author)rowerwet2009-06-30

Can you post a picture?

Jouda Mann (author)2008-07-24

I wonder if this can be optimized for keeping mosquitoes out. I live in nort Texas, and there is local legislation being discussed which will outlaw standing water because of the dangers of West Nile and so on. Could your design be modified to something like this?

jesmedley (author)Jouda Mann2009-06-29

I just toss a mosquito "dunk" into the barrel.

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