Introduction: High Volume Rain Barrel

Picture of High Volume Rain Barrel

My wife and I purchased an esthetically pleasing rain barrel for the front yard. After experiencing the benefits there I began looking to build my own system for the backyard for the garden, the landscape, and for play. As I reviewed many online plans and products, I found a number of good ideas. This design I developed differs in that it does not require any drilling/cutting of holes in the barrel for the water flow and the volume of water passed through the system, especially the output, is as high as possible, limited only by the attachment at the end of the hose.

In my case, I knew we wanted a 2 barrel design, the same plan can be followed for a single barrel design. Modifications will be noted throughout the instructable.

Step 1: Out Flow Parts List

Picture of Out Flow Parts List

Here are the parts that I used and the price. This is for building the piping and valve assemblies to draw water out of the barrel. The parts needed for bringing the water into the barrel are handled separately in step 4. All of the following parts can be purchased at Home Depot.

2 2" DWV MIP Adapter - $0.90 each

2 2" DWV Street Elbow 90 degree Spigot x Hub - $2.01 each

1 2" PVC Pipe (2' section pre-cut) - $2.21

2 2" PVC Tee - $2.49 each

2 2" x 1-1/2" PVC Drain Waste Vent Flush Bushing - $0.86 each

2 1-1/2" x 3/4" PVC Schedule 40 Bushing Spigot x FIPT - $1.27 each

2 3/4" Short Galvanized Nipple - $0.98 each
** I chose not to use this but instead got the PVC schedule 80 (gray) equivalent from my local Ace Hardware for $0.79 to prevent as much metal in the design as possible.

2 3/4" PVC Ball Valve - $2.94 each

2 3/4" MPT x 3/4" MHT adapter - $3.53 each
** While my local Ace Hardware did have this piece in plastic for less, I chose to go with brass here to better withstand contact with the metal threads on my hoses.

1 can of PVC primer and cement - $6.96

For a single barrel design you do not need the Tees or the PVC pipe. You have the option to change the 90 degree Street Elbow with the 45 degree Street Elbow to reduce the bend of an attached hose.

Step 2: Building the Valve Assembly

Picture of Building the Valve Assembly

To build the valve assembly:

1. Screw the 3/4" MPT x MHT (Male Pipe Thread to Male Hose Thread) adapter into one end of the threaded valve.

2. Screw the 3/4" nipple into the other end of the threaded valve. Screw the other end of the nipple into the 3/4" PVC Schedule 40 Bushing Spigot x FIPT (Female Internal Pipe Thread).

3. Insert the assembled parts into the Drain Waste Vent Flush Bushing (2" to 1-1/2" reducer) and then into the 2" Tee.

About sealing the joints:
I found that friction was all that was necessary for the valve assembly. You can also use plumbing tape or PVC cement for the non-threaded joints.

For the single barrel design, you will not use a Tee in the assembly.

I chose to use this design over other designs I found online because of the volume of throughput. Other designs using different spigots or hose bibs would reduce the volume of the water coming out of the barrels as well as the gravity fed pressure. With this design I am able to have 2 hoses connected both receiving almost the full 3/4" diameter of volume through to the hose threads (see the final picture of the volume through the valve assembly). The bottleneck in this system is not the valve or piping, but the 5/8" hose or attachment at the end of the hose.

Also, have younger kids who love to help in the garden, the plastic valve offered the ease of use I wanted for them to be able to fill their watering cans or water guns.

Step 3: Connecting the Valve Assemblies to the Barrels

Picture of Connecting the Valve Assemblies to the Barrels

1. After guaging the positioning of where your barrels will be, determine the spacing between the barrels and specifically between the pipe-threaded bung holes.

2. Cut the 2" PVC pipe (standard hacksaw will do), cutting two small sections for connecting the Tees to the Street Elbows and a larger section for between the two Tees.

3. Insert the pieces between the elbows and tees to make one complete unit.

About sealing the joints:
Using friction or plumbers tape in the joints will allow you to customize the angle of the valve assemblies. If you find that it is leaking, you can cement the joints later. I found this to be beneficial as we could adjust the angle of the spigot assembly to account for filling water cans, water guns, or other items.

4. Remove the two pipe thread bung plugs from the barrels. These are the plugs that do not have the internal threads in the center of the plug.

(I removed the gaskets from the plugs and put them onto the 2" DWV MIP Adapters but this proved unnecessary as the PVC adapters did not screw all the way down into the barrel anyway.)

5. Screw the 2" DWV MIP Adapters into the bung holes of the barrels until tight.

6. Insert the street elbows into the adapters.

With this, the outflow system is complete.

For the single barrel design, insert the vavle assembly into the 60 degree Street Elbow. Insert the elbow into the 2" DWV MIP Adapter.

Step 4: Connecting the Barrels to the Downspout

Picture of Connecting the Barrels to the Downspout

We had a leftover downspout diverter from the Fiskars Rain Barrel that we installed at the front door. I used this to supply water to the barrels.

If you choose to use a downspout diverter, there are a number of models available on the internet which connect in different ways. While purchasing one will add approximately $30 to the cost of your project, it will also allow you to use your existing downspout system for handling the rainwater when the barrels are full. See for a video explanation of how they work in general.

The most common way for filling the barrels is to cut a hole at the top and install a screen over it to keep out debris and mosquitos. As stated above you must also plan for run-off once the barrel is full. As I already had the spare downspout diverter, it allowed me be create a completely contained system. The only holes drilled into the barrels are a series of 5/32" (smallest drillbit I had with me) holes in the top of the barrels to balance the air pressure in the barrels as they fill and empty.

These are the parts I used for connecting the barrels to the downspout, all from my local Ace Hardware:
1 3/4" MIP to 5/8" barb adapter
4' of 5/8" ID (internal diameter) clear tubing
**This hose fit into the opening of the downspout diverter and also allowed for a larger volume of water to enter the barrels at one time.

1. I used a 3/4" spade bit to drill out the bottom of the one of the internal threaded bung plugs, being careful not to damage the threads.

2. I screwed the bung plug back into the barrel so as to use my homemade wrench to ensure it was tight.

3. I screwed the 3/4" MIP to 5/8" barb adapter into the threads of the bung plug.

4. I attached the tubing to the barb and secured it with a clamp.

5. I followed the instructions with diverter to install it into the downspout and then connected the clear tubing to it.

Step 5: Setting It All Up and Enjoying Free Water

Picture of Setting It All Up and Enjoying Free Water

1. Make a level base for the barrels. I used large concrete blocks to raise the barrels off the ground to provide clearance below the spouts for watering cans, hoses, water guns and such. I tilted the blocks slightly to the back to prevent accidental tipping.

2. Position the barrels on the blocks so that they are well supported. I have not found any need to secure them to the back wall of my garage.

Free Water:
With it all in place, I waited for it to rain. A few days later, we received a .21" rainfall. I harvested about 55 gallons from that event. Filling the watering can has never been so fun.



Aquabarrel (author)2013-11-04

For a less complicated rain barrel parts group this might work for a lot of folks:-)

David Catriel (author)2010-07-25

Very nicely done. The barrels, though - where did you get them? Are these specifically made for rain collecting or did you repurpose them from something else?

gearskin (author)David Catriel2013-05-17

You can pick up drums like these from your municipal water authority (often for free) or from just about any power plant (just call them - the worst they'll say is "no", but often they're happy not to pay for disposal). Basically, any of these drums will be safe for use after a few rinses - the chemicals that the drums originally contained have been in use in water treatment for decades.

jaminlive (author)2013-05-13

Hi, there is some great info here. Thanks already
I'm about to build my rain barrel system and I'm a bit torn and to which system to go with.
1. The overflow at the top fills the next barrel (one barrel could be full and the next could only be half full)
2. They connect at the bottom and all fill evenly at the same time.

My question is, does one style/system have a benefit over the other?
Will one system deliver more pressure than the other.
Thanks in advance

gearskin (author)jaminlive2013-05-17

With the overflow at the top connecting the barrels, you will need valves in the common discharge line (below the barrels) to isolate the full barrels from the barrels being filled - otherwise, the level between the barrels will automatically balance.

A full barrel will have a higher head pressure (0.43 PSI per foot of "head", or level of the water above the level of the discharge) than a mostly-empty barrel.

In my system, I have a single fill from the gutters in the lead barrel, a common header connecting the underside of all the barrels, and a valve between each barrel on the common header. I have an extra valve at each end of the common header - one valve is attached to my discharge hose (for using the water). The other valve is in place for draining the tanks as well as to provide future expansion by adding more barrels.

gafarmboy (author)2011-10-05

Very Well done. The step-by-step process was well thought out with excellent instructions. I will be working on a similar project this weekend using this tutorial as a guide.
Thank you

Eric T (author)2011-05-25

If you thredd a steel pipe niple into those bung plugs "caps". The plastic plug breaks out. No drilling is required. = Less chance for blood :)

LandMime (author)2010-07-25

I live in Indiana and the problem I had with using a plasic valve is even though I emptied the barrel prior to winter enough water sat in the valve which froze and caused it to crack. I would suggest metal for cold climate valves.

thebigbarn (author)LandMime2010-08-02

This is why I have not "cemented" all of the joints together. I trade off the occasional drip for the ability to take the outflow unit off the barrels and take it inside for the winter. That way I could have the high volume throughput of the plastic valve when I needed it and protect the hardware inside when I did not need it.

jpatano (author)2010-08-01

Great instructable!! I just ordered a diverter, and I found someone locally selling barrels for $20 each. Looks like I will have a fun little project for next weekend. I originally had a question about how well the barrels would fill due to the input hose being at the bottom, but I then saw it had been answered in another comment.

buteomont (author)2009-10-01

Nice 'ible, but where do you get the barrels?

threewheela (author)buteomont2010-07-26

Car washes oftten give these barrels away for free. The liquid soap they buy comes in these 55 gallon drums and whats left over in them when u get them can be easily washed out.

thebigbarn (author)buteomont2009-10-01

I looked on the internet for local suppliers. I got one from a guy listing them on Craigslist for $25/barrel. Now that this idea is gaining in popularity, I found it harder to find people just giving them away so they don't have to bother with them.

scratchr (author)thebigbarn2010-04-25

Just ask the water treatment plant.
They use them for cleaning chemicals.

handprints (author)thebigbarn2009-10-18

Great instructable!  I called all of our local bottling companies and they ranged in price from $30 each to $10 each.  the $10 was at our Pepsi bottling company.  We were able to fit 9 in our truck.  I think it was a little overkill on my part, but they are useful things to have AND if I don't use them all, I'm sure someone else can use them.

dugthegreat (author)2010-07-26

You are not in a earthquake zone ; So I understand you do not need to secure it . I live in a earthquake prone home; so I think there is a need to secure the rain barrels

Buzzinski (author)2010-07-25

Nicely done. This is what we use in Australia. typically all new home built here (Queensland) have to have a rain water tank (Barrel) of a minimum size -( from memory I think it is 5000 litres) installed prior to the final building inspection. Not a bad idea for a very limited amount of storage but 3 small suggestions. 1) Pour a concrete slab under the blocks to stop them falling over. 2) use flexible hose instead of rigid plactic pipes between the barrels. If one tilts or falls the flexible hose will not break like a rigid pipe will. 3) Raise the barrels another foot and you will get more water pressure for a slightly longer hose run.

Kindlekat (author)2010-06-04

This was SUCH a great Instructable! I actually became Pro just so I could download the PDF and see all the pictures. THANK YOU for individually labeling and taking pictures of all the PVC parts. While I am quite the handy gal (I work in a theatre scene shop, and know my way around more power tools than the average joe) I was not as familiar with the plumbing. With your clear lists of parts, I was able to find everything I needed at Home Depot with some help from an associate, and make an easy substitution when they didn't have one of the parts I needed. My system is fully built now and tested, I have one or two slow leaks, but I should be able to remedy that with some PVC cement soon. I researched a lot of these rain barrel systems here on Instructables, as well as the internet in general and by far your design was the easiest to follow, assemble, and made the most sense. I will be posting pictures soon!

Kindlekat (author)Kindlekat2010-06-07

Wanted to add the pictures of my finished system! Because I did not have the downspout diverter, I picked up what looked to be a downspout adapter and used that. I also used a barb adapter in the top of my barrel, for overflow, and those were my only changes. Thanks again!

thebigbarn (author)Kindlekat2010-06-08

I'm glad you liked the design and that it is working for you. Keep in mind, the volume of water coming into the tanks from the downspout during a heavy rain will be more than can be carried away through your outlet hose. When the barrels are full and it is raining heavily, you may have an overflow situation. Happy watering!

Kindlekat (author)thebigbarn2010-06-11

I definitely expect some overflow in a heavy downpour, which I've accepted as my fate when altering the design. However, I just tested the barrels at half-full and there wasn't enough pressure to get anything out of my hose at all. I'm hoping that once they are full there will be enough pressure. Also, I was using the 100-150 foot hose the previous renters had left, which I suspect might be the problem. It might just be too long of a hose to keep the pressure going, so I will get a shorter hose and see what happens.

Kindlekat (author)Kindlekat2010-07-12

The hose was definitely the problem! A 25' 3/8" hose works perfect!

EmilinIowa (author)2010-07-09

I found an 1100 gallon barrel/tank on Craigslist. It now resides beside our barn with twin inputsfrom barn roof, North side direct, South side piped over and the tank is full. Two valves with hose connections water the garden, horses, etc.

thebigbarn (author)EmilinIowa2010-07-09

Great job supersizing the project. That would be awesome!

nuttman (author)2010-06-21

From the picture, it looks like the rain diverter is slightly below the top of the barrels. Is this correct? With the holes for balancing air pressure, I would think the diverter must be below these; Water overflow would come out the top of the barrel through the holes, rather than backing up the diverter. I've been thinking about taking 1/2" PVC pipe and making a "periscope" out of the tops of the barrels for balancing air pressure. The diverter could be mounted slightly higher than the top of the barrel, and the periscope would extend above the diverter. Any thoughts on this? Do you have water come out of the top holes when the barrels fill completely?

thebigbarn (author)nuttman2010-06-21

It can be a little deceiving. Inside the diverter is the overflow lip. The port for the tubing to connect to is below that. Therefore it appears as though it were lower when it is not really. It is balanced so that I have the barrels almost completely full. I have not had water come out of the air holes on the top. I'm sure the 1/2" PVC periscope would do the job for balancing the air pressure, but I think it is more than you need. The 8-12 5/32" drilled holes are working fine for regulating air pressure when filling and emptying the barrels. If you proceed using that design, you should make sure that you have a screen on the PVC to make sure that you're keeping out mosquitoes and other "undesirables".

nuttman (author)thebigbarn2010-06-23

Screening is a must! Anyway, my point was that anyone using a diverter such as this (mine is a RainReserve) must be aware of the mounting level in relation to the top of the barrel. Too high, and water will want to overflow through the top of the barrel rather than back up the tube to the diverter as intended. (In a heavy rain, I'll bet the pressure of the water trying to get out through the little holes may still back up to the diverter.) The vent pipe idea (or "periscope") simply allows for some leeway in the mounting height of the diverter. As long as the end of the vent pipe is above the overflow mouth of the diverter, there should be no problem. It's all about water seeking its own level. I think this is what's great about these projects. There's so many ways people can customize them. Thanks for all the great information and details you provided about yours!

Cyraxlynx (author)2010-06-05

wow this great...

dcole64 (author)2010-06-04

Hey Barnsie! Congrats on being a 'featured' project. Now I just have to figure out how to modify it for our southwest gutters and a rain chain.

Taztrophe (author)2010-05-22

Absolutely love the simplicity of your design. I've been browsing looking for the perfect configuration for my barrels and your plan looks perfect. I'll be doing a homemade filter for inflow as I'm diverting the whole downspout versus buying a diverter but rest looks great.

My only question is why did you decide to put two ball valves for outflow on your system versus one? I had planned only one but I'm interested to hear your experience before I commit either way.

thebigbarn (author)Taztrophe2010-05-24

I chose to use this design over other designs I found online because of the volume of throughput. Other designs using different spigots or hose bibs would reduce the volume of the water coming out of the barrels as well as the gravity fed pressure. With this design I am able to have 2 hoses connected both receiving almost the full 3/4" diameter of volume through to the hose threads (see the final picture of the volume through the valve assembly). The bottleneck in this system is not the valve or piping, but the 5/8" hose or attachment at the end of the hose.

With two spigots I can leave a hose attached for regulary watering of the garden plants and have a spigot available for filling a watering can or other container there at the barrels.  You could use a Y splitter, but again that reduces the volume.  Once I settled on using the 2" diameter PVC, that freed me up to have two separate spigots that do not have to "share" the piping leading to the spigot. 

wingrider78 (author)2009-10-23

Do your barrels fill completely???  I was under the assumption that they needed to be filled from the of the instructables I read said that the water will only rise as high as the entry point of the with it being at the bottom, I wouldn't have assumed that the barrels would have filled.  I must have misread something somewhere...

How can water coming into your barrels in a 5/8 line compete with the pressure of the rising water to completely fill the barrel???

thebigbarn (author)wingrider782010-05-14

[My previous response got deleted while editing.  Reposting.]

I understand the skepticism.  I tested the theory myself first with a watering can and then with our purchased, top-loading, rain barrel before building this.

The key to it is gravity.  Water will always find the lowest point and settle there.  As an illustration, think of your standard 2 gallon watering can.  Even though the total volume of water in the can far exceeds the volume of water in the spout, it does not push the water out of the spout.  Instead, gravity pulls it all to the bottom.  The water comes out of the spout only when the spout  is lower than the level of the water.  Likewise, this design fills my 110 gallon "watering can" through the spout instead of through the opening at the top.  With the diverter positioned in the downspout so that it is level with the top of the barrels, I gain the maximum capacity.  The point to keep in mind is that the diverter is the true entry point to the storage system, not the connection point of the hose to the barrel.

A key to a successful implementation is the drilling of the air holes in the top of the barrel(s).  This releases the air pressure in the barrels.  Without them, when the air pressure inside the barrels is greater than the gravity-driven water pressure coming in through the tube, the water will build up in the supply tube and then go down the downspout.  With the air holes, it fills and empties beautifully.

northwoods74 (author)thebigbarn2010-05-14

Oops--one last question.  Did you use pvc cement on all the parts (except for the ones with threads)?  I'm assuming you did, and as I look at my parts I have one concern: once you get the whole thing together, is there any way to get it apart?  Seems like it would be hard to get the outflow assembly off the barrels if there was ever a problem.  No biggie, still a fantastic setup, just wondering if you had a solution for that.  Thanks!

thebigbarn (author)northwoods742010-05-21

It is noted in steps 3 and 4 that I have simply used pipe thread tape and a rubber mallet to tap the joints together securely.  While there are a few drips now and then, it gives me the flexibility to adjust the angle of the spigot assemblies (different heights for watering cans, buckets, water guns) and also to take the entire outflow assembly off and inside for the winter (your second question). 

I did look into adding another section of 2" PVC pipe to the 2" DWV MIP Adapter and another section of 2" PVC pipe to the DWV Street Elbow 90 degree Spigot x Hub and then using a 2" to 2" Flexible Drain Coupling ($4.33) to connect them.  This would allow for the whole thing to be cemented and yet portable.  I chose not to do this because it would make the entire outflow system much bigger.  In order to compensate for that I would have needed another four concrete blocks.  The cost of the couplers and blocks would have added another $10 or more.

There is also the option to replace the PVC 90 degree elbow with a 2" Flex Quik Elbow ($7.66).  Again, they are significanly more expensive than the PVC elbows ($2.21) but it would be a tight seal.

northwoods74 (author)thebigbarn2010-05-14

Thanks for the reply--can't wait to try it!  Great instructions, by the way--especially the part where you use Home Depot's actual terms for the parts :)

northwoods74 (author)2010-05-13

I second Wingrider78's question; I don't understand how you can be filling that thing efficiently through the bung on the bottom--wouldn't the pressure of even a half-full barrel push the water right back out the hose and up into the downspout?  Can you please explain?

thebigbarn (author)northwoods742010-05-14

(Previous response had been deleted accidentally.)

Jakeg (author)2010-05-01

     I know that I commented on this before but I since I decided that I am going to build this I need something from you. I was just wondering how long is this setup from the edge of one barrel to the edge of another.


thebigbarn (author)Jakeg2010-05-05

The barrels are 2 feet in diameter.  So the layout is essentially 2 deep and 4 feet wide.

Jakeg (author)thebigbarn2010-05-05

OK, Great... I just needed that info so I could set it up on the side of my house. Its on a hill so I have to dig it out and pour concrete to make it level. Once again, Thanks =]

Jakeg (author)2010-04-23

I am so excited that you posted such great, informative information for all of us people... I am definitely going to work on doing this project for my summer home. We are actually just starting a garden now and my mom wanted a better, greener way to feed the garden veggies. Once again I thank you for such a great instructable. =)

wingrider78 (author)2010-03-18

Hey many of those 5/32" holes did you have to drill to allow the barrels to fill and empty smoothly??  I have purchased a diverter and am just waiting for it to come now so I can build the system in your instructable...I can't wait :)

thebigbarn (author)wingrider782010-03-19

From memory, I think 8-12.  You can test by drilling some holes and then letting out some water into a watering can.  If you can hear air being sucked in through the holes after you have closed the valves, then you need more holes.

qman007 (author)2009-11-24

Is there any reason you didn't use a 3/4" drill bit and use the existing threads that were in the cap?

thebigbarn (author)qman0072009-11-25

I don't understand your question.  Instructions 1 & 3 in this step outline doing just what you asked.

handprints (author)2009-10-18

We get a LOT of rain in our valley.  Should I use larger tubing than the 5/8"ID??
I live with skeptics!

thebigbarn (author)handprints2009-11-11

It depends on the hardware available to you.  I chose that size of tubing because the ID (inner diameter) fit with the size of the hole that I drilled into the bung plug.  If you try to drill the hole much bigger, you will damage the threads that the adapter screws into.  Also, the OD (outer diameter) of the tubing fit nicely into the port on the downspout diverter.

I found that it fills the barrels nicely.  When it is a hard rain, not all of the water is collected by the diverter.  However, when it is filling at full volume the level rises quickly.

aunthill (author)2009-11-07

There is also a really cheap way to connect barrels here at

I think it holds about 600 gallons too.

Paperworker99 (author)2009-10-08

howmuch does it cost

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