Introduction: DIY 275 Gallon Rainwater Collection

Picture of DIY 275 Gallon Rainwater Collection
I recently helped my father install a 275 gallon rainwater collection system.

The system is based on an industrial 275 gallon container, known as an IBC. You can buy them used, or if you really look around, you can even find them for free. One problem with typical rain-barrels is that they can only collect 55 gallons. This rain storage container collects FIVE times that volume, while not taking up all that much more space than a single rain-barrel.

In my area, you can buy used IBCs through Craigslist for about $85 each. Those come with a metal cage around them that allows them to be stacked.

Instead of buying them, I found a local bottler who throws them out, because they are plastic containers WITHOUT the metal cages. These containers come to the bottler full of 275 gallons of high-fructose corn syrup. I got several containers from them for free, for just the elbow grease of going to pick them up. Some were wrapped in heavy cardboard. I recycled the cardboard into a clubhouse for my little girl.

After washing the container out well, it is ready to be repurposed for rainwater collection. I really like the irony of using GMO corn syrup containers to recycle into a conservation project!

Besides the water container, this project requires other materials, including:
  • Misc wood to build a simple pallet or platform
  • Garden hose spigot and hardware
  • Gutter screen and fiberglass bug screen
  • Gutters, downspouts, and elbows
  • Silicon or other appropriate caulk or sealant
In our case, nearly all the materials were already on-hand, reusing old components, and recycling and repurposing materials. Total out of pocket expenses were under $20.

Beyond the typical DIY and handyman tools, you will need:
Tin snips, utility knife, pop-rivetter and rivets, sheet metal screws, and related aluminum metal-working tools and skills.

Lets get started.

EDIT: July 2013, we updated this to TRIPLE the capacity, raised the containers, and made them look really nice. See the update at:

Step 1: Locating the Storage Tank

Picture of Locating the Storage Tank
The first thing you need to do is decide where you want the container to go.

It needs to be located near the building you want to collect rainwater from, and it also needed to be elevated if you want it to work on gravity flow.

In this case, the building is a 100 year-old barn that was remodeled into a home office. The roof is a fair amount of collection area, and the building is on the top of a hillside - it's basically the highest point on the property. Because of that, the container was NOT put on any kind of a stand.

There was a small rock garden right outside the barn that was slightly elevated. We leveled off a 4'x4' area there for the tank.

That corner of the barn is also right where the downspout from one side of the roof is. That will make it a short distance to route the downspout to the tank.

Next, we built a pallet out of scrap pressure-treated wood for the container to go on. This gives the container a solid base and gets it up just a little higher, making it easier to access the garden hose spigot we will add.

The front of the pallet has a notch around the drain port, which will make it easier to access the garden hose spigot later.

Step 2: Modifying the Tank Fill Port Cap

Picture of Modifying the Tank Fill Port Cap
Next, we need to modify the inlet of the tank so that we can get the rainwater in, without letting in leaves or anything else.

The fill port in the top of the tank is a 6" screw-on cap. Just removing the cap leaves a nice big hole to let things in, but even animals could get in there if you did that!

So, we decided to modify the cap to include a screen, make it self-cleaning, and keep out mosquitos.

First, we notched out the edge of a 4" PVC pipe cap wide enough for a gutter downspout using a jigsaw.

Next, we centered the 4" pipe cap on top of the 6" cover. We then drilled holes around the inside edge so we could use pop rivets to connect the two. After trying a rivet, we realized the rivets we had were EXACTLY the wrong length, so we used some sheet metal screws instead. 

Then we drilled through both the pipe cap and cover with a 3" hole-saw. That kept a half-inch lip all the way around the inside of the pipe cap for the screws that held both parts together, AND as a place for our "Coarse-Filter" to rest.

To keep large items out of the storage tank, we needed some sort of screen. Since we had some aluminum "gutter-guard" around, we traced the 4" pipe cap onto it with a marker, and the cut the inside of the line with a tin snips. We then had an aluminum circle that fit inside the pipe cap, and would rest on the ledge inside. I friction-fit in place just fine, but you could add some sealant to make it more permanent if you wanted.

Lastly, we cut some scrap fiberglass bug screen to a little bigger than the cap. We simply laid the screen over the 6" hole, and then screwed the cap back on top right over it. That way, there is both the aluminum coarse filter to keep leaves out and screen to keep out mosquitos.

Step 3: Converting the Drain to Garden Hose Connection

Picture of Converting the Drain to Garden Hose Connection
The 275 gallon IBC features a 2" drain port on the front bottom. It has a cheap plastic ball shut-off valve, and a 2" plastic cap that gets screwed on to keep it from leaking.

Rather than use a number of PVC pipe adapters to get down to a garden hose, we reused the 2" cap and some spare plumbing parts we had kicking around.

To start with, we had a brass spigot with 3/4" NPT (National Pipe Thread) male connection on it. Standard threaded pipe is tapered, so the farther you screw it in, the bigger it gets. This helps make solid, water-tight connections.

We drilled a 3/4" hole through the center of the 2" drain cap.

Next, we stuck the pipe end of the brass spigot through the cap, added some sealant at the joint, and then threaded on a nut from the back side. Since the hole was the right size to start with, the sealant and tightened nut made a solid connection on the cap.

We then headed back outside. Using plumbers putty (you could also use teflon tape) we threaded the drain cover with spigot onto the drain.

We decided to have the brass spigot rotated clockwise part-way, because the open big drain valve made it harder to grab the knob on the spigot.

Then we connected a garden hose, ran it down-hill, and tested our flow from the rainwater collection system.

Step 4: Gutter Work

Picture of Gutter Work
Now for the tough part - modifying the gutters and routing them to the storage container.

For the gutter closest to the rain container, it was pretty straight-forward. We cut the downspout a few feet above the container, and then set the cut-off piece to the side for later use.

We also wanted to collect all the water from the other side of the roof as well. To do that, we added two elbows to snake the downspout around the back of the barn, and then a long section of angled downspout sloping downward, towards the rain container.

We had to figure out the best way to connect both gutter downspouts together to combine the water going to the rain container. After a little thought, we decided that the best way to do it was to use another short piece of gutter. Not only did we need to combine both downspouts, but we also needed to move the water sideways a couple of feet and then send it to the IBC. A short piece of open gutter could accept both downspouts AND extend to the IBC tank. It would then have an elbow and short downspout going directly to the the fill port on top of the tank.

I had never worked on any gutters before, so I got a lesson on working with aluminum, sealing it, and in the mind-set of how water flows. About half an hour later, I had created my very first custom gutter. I then attached it to the wall of the barn with some long screws, and a slight slope towards the rain container.

We now had a rain collection system - two gutters, whose downspouts combined into a short gutter, which lead directly to the rainwater storage.

Step 5: Learning Experiences and Future Improvements.

Picture of Learning Experiences and Future Improvements.
A little back of the hand math, ball-parking the size of the roof compared to the volume of the container, told us that one inch of rain would be enough to fill the whole container. Sure enough, when we finally did get some rain, less than an inch filled it most of the way up!

After we installed the gutter modifications, we cleaned the gutters real well. This is a typical asphalt shingle roof, and the grit from the shingles DOES come off. We flooded the gutters, and rinsed the entire roof, with the output of the gutters diverted from the storage tank. Next, we are adding gutter-guard screens to the full length of both gutters, as well as our short section that combines both downspouts.

Although a metal roof is ideal for rainwater collection, this building was re-roofed not long ago with the asphalt shingles. The water will be used for general irrigation, and not for watering animals or human consumption.

Because of the angle and direction that the downspout goes into container, it makes a good point to add an extra section of downspout to just "overshoot" the storage tank. For example, that's what we did when we washed the roof and cleaned the gutters. Some people use a "roof-wash" system - that's a way to DIVERT water away from your storage container at the beginning of a rain storm, so that the water washes the roof clean, once it's clean, the system then allows water to go to the storage container. This is often accomplished with a spring-loaded bucket contraption that uses the weight of the water filling a bucket to then connect the diverter to the water storage container.

If we want to add a "roof-wash" diversion device to the system, we will most likely add it right before the tank's fill port.

One thing that I learned the hard way on this project... DON'T fill the tank all the way up with water for experimenting! When I was putting up the short section of gutter, I had to work around the tank. I didn't have a good place to lean the ladder, and I was working at odd angles with the screw driver to put up the gutter. If I had just left the tank empty, we could have simply moved it out of the way!

After the first big storm and some hot weather, we noticed that the shape of the tank bulged and distorted a bit. It's not that it was going to rupture or anything - mostly it just looked really bad. Many of these tanks come "caged", which helps them keep their shape and makes it possible to stack them when full in warehouses. Since this container isn't caged, we are thinking right now that we will box it in with wood, to not only help it keep it's shape, but also make it match the barn and chicken coop. The wood boxing could also keep out sunlight, to prevent algae growth.

This is the first LARGE water collection system I have worked on. It is slightly experimental, and I expect that we will add some improvements in the future. In the mean time, I hope that our work on this system gives you some great ideas on how you might want to collect your own rainwater!

UPDATE: Early Summer 2013
We are increasing the size of the system to TRIPLE the original capacity and building it on a raised platform for better water pressure and gravity flow.

Besides tripling the size, the tanks are boxed-in, making them look nice and keeping sunlight out. A site-guage is added on the side to tell how much water there is, and an outdoor wash tub was added to the end. The drain of that washtub gravity feeds to the waterfall and pond just to the side.


Trailheadache (author)2016-07-28

I'm late to the party here. Love this instructable. I never knew about these containers till I saw this post. Unfortunately up here,those containers go for a pretty penny, 150-250 for food grade. Hope I can find cheaper. Thanks for posting.

markgrogan (author)2016-04-23

At some states, water collection is illegal regardless of whether or not the storage container belongs to you. Even though rainwater is free but to collect it and eventually using it for your own personal benefits seems to be an issue to the authorities I suppose. Sad, but definitely true.

kurtnotkirk (author)2015-05-10

I just got my hands on one of these ibc containers for $20. Great instructable! Going to use your plan for the filter/cover mod!

bgunville (author)2014-02-26

Just make sure that the IBC was not used in harsh chemical usage. I made them for years and the 55 gallon drums. Your best bet is to get them from someone that had food grade usage and the IBC was made for food grade usage. Also if you can find out if it was made with Ultra Violet additives. (helps keep the algie out)

bennelson (author)bgunville2014-02-27

True, I try to avoid harsh chemicals in all ways I can. In this case, picked up these IBCs from a beverage bottling company. They originally contained corn syrup. We simply washed the containers out well.

tim_n (author)2013-08-28

I've got a similar system at my house which takes water from my garage and man cave roof. I've not boxed them in yet. It's on the to do list. Currently they're covered in winter squash, so adequately shaded!

criggie (author)2012-08-02

I have something similar on my carport for the past 10 years or so.

What happens to the overflow when your tank is full? I had to add a 25mm overflow hose down to the drain, so that the barrel doesn't flood out the top.

How to get pressure? Your tank is almost at ground level so there's not a lot of differential. Mine's about 500mm off the ground, so can still push water down a hose. Could use a pump to generate pressure.

Our need for water drops right off in winter - I'm tempted to just take the tank out of the line to stop collecting roof dirt.

Finally green shit - it grows. If you do box in your tank then make sure there's a way to get it back out for a scrub.

jchamberlain (author)criggie2013-03-03

I was reading this and thinking the same thing. Worse thing to happen would be the overflow is improperly directed to a wash or your septic tank area.

bennelson (author)criggie2012-08-03

The tank is on the highest point on the property, and is on top of a rock garden, which gives it just a little more height. Instead of being on a stand, the tank just happens to be higher than everything that it will water.

The tank doesn't have an overflow yet. (We have been in a major drought, so it hasn't been an issue yet....)

The plan is that we will add an overflow right at the top where the water inlet is. We might design a "roof-wash" device there as well.

gjm (author)2012-08-02

I am amazed that any state in this country COULD make it illegal to collect rainwater.
It falls from the sky, no one owns it.
If it lands on my property, I should be able to collect it.
I've never heard of anything so ridiculous in my life; I'm really pissed off just reading about this.
I don't know if it's illegal in my state and I don't care; people have to draw a line somewhere and if the state wants to send me to jail, let's go.

Sorry for the rant; great instructable by the way.

Bosun Rick (author)gjm2012-08-03

If it falls from the sky, or is ambient to the earth, it is a gift from God. Obama & Co. apparently don't believe in God, thus making it illegal to own rain or air. What does this mean for the solar collecting community?

zanne101 (author)Bosun Rick2012-10-09

The laws are local, not federal!

JettaKnight (author)gjm2012-08-06

Around here, (Indiana) cities want you to do whatever you can to capture or use rainwater. We have a problem with storm water and the overall waste water processing system can't keep up in heavy storms.

bennelson (author)JettaKnight2012-08-06

Milwaukee, Wisconsin also has a huge problem with the sewer system. Any time there's a big rain-storm, it ends up causing untreated sewage to go right out into Lake Michigan.

If everyone collected rainwater, it would help with the problem.

aldebaraan (author)gjm2012-08-05

Not that new a concept actually, some countries in Europe have been taxing for rainwater for a long time, all based on square footage of property.

ehensel1 (author)gjm2012-08-02

Gjm- This is a pretty recent news story, relevant to the law. Don't get me wrong, I totally agree with you, but it's crazy what the government can do. I just hope I'm not stealing air from the state when I run my air compressor!

Great Instructable by the way!

trehak (author)2012-09-27

How do you take care of mosquito's?

bennelson (author)trehak2012-09-27

The top has bug screen on it.
Mosquitos don't get in, so there's no problem with them.

Beergnome (author)2012-08-02

I like it!
check out my profile for the "rain barrel" I made that collects condensation water from a second floor air conditioner air handling unit.. thing produces around five gallons a day during the hot and humid months around here. Sometimes I produce more drip water than I can use, so a large container like that would be even better... there's a guy selling the metal caged IBC down the street from me, but I haven't checked out how much he's selling them for. most likely he's picking them up for free as well.

bennelson (author)Beergnome2012-08-02


Too bad the window unit built-in to the wall of this barn wasn't just a tad higher. The IBC could have gone right under it!

Oh well, as it is, it just drip irrigates the plants below!

I spoke with somebody last week who said that they collect their AC condensation drip water for watering plants. I love the idea of using a "waste" product like that!

Beergnome (author)bennelson2012-08-03

Yep, my device is in it's second year of operation, and it was a god send during the biggest part of this years heat wave and with no rain.

and it is a shame that wall mount unit there isn't just a smidge higher. however. you can get little sump pump things for AC air handler units that pump the drip water away.

we have them on all our refrigeration units at the brewery, to pump the condensate away and out of the building and that is their purpose. you most commonly see them attached to commercial ice machines that have to be located away from a drain source.

with this is in mind, one COULD locate one of these devices under the water drip area under the wall unit AC and pump the drip water into the collection tank.

keep in mind though that units like that rely on the condensation water as heat exchange process so you only want to take it away as it gets rid of it. no punching a drain hole into the under carriage of the unit.

RuntB (author)Beergnome2012-08-29

Be careful with condenser coil water. Those coils are usually copper. Copper is poisonous in large amounts. Bonsai growers use copper wire to train branches. The plant will try to grow away from it. Also used to hold screen in potted drain holes; so roots stay back.

I actually killed 2 of my 3 burning bushes when my A/c froze up. And stunted the growth of the nearby cherry tomatoes.

Mine was the drain from the house's central air unit, so it may be different...

Just a warning for expensive plants.

XLS (author)2012-08-12

I hope it is not against the law where you live to collect water.

Ex: "Oregon Man Jailed For Collecting Rainwater On His Own Property"
"Collecting rainwater now illegal in many states"

Even in other states like Utah, California, etc.

As another link states "If states claim they own the rain, they may soon claim to own the sunlight, too.

Anyway, Some car washes throw away 50 gallon drums sometimes. They has soap in them. They say it's harsh and warn people to clean them well. I find that hard to believe.

Bujholm (author)2012-08-08

Best to put a roof over that tank or paint it - anything to prevent direct sunlight. As all aquariumists know, immobile water (it' s bound to be at least partly immobile given the volume) exposed to sunlight sprouts life of its own very quickly - mold/mildew not only spoils the water but are also tough to clean.

gingertux (author)2012-08-04

What arethe deminsions of this IBC. I don't have access to a pickup and only have a station wagon. I'm afraid it might not fit inside and might have to be strapped to the top.

bennelson (author)gingertux2012-08-06

IBCs are 40"W x 40"T x 48"D

Harley3216 (author)2012-08-04

Beware green slime...cover the container with opaque black thick plastic first

lej619 (author)2012-08-02

thanks!! if i could just get a 55gallon tank in my backyard i would be happy.! but a 255 gallon wow that would be awesome!!!!! thanks ! i am now going to have to start looking on craigs list for one.

letstormdufield (author)2012-07-31

Did you know that this is illegal in Utah, Oregon and Colorado?
But still, great Instructable.

msj113 (author)letstormdufield2012-08-02

no longer illegal in colorado


letstormdufield (author)msj1132012-08-02

Is it?

hpebley3 (author)letstormdufield2012-08-02

Just FYI, as of May 2010, it's no longer illegal in Utah to collect rainwater.

letstormdufield (author)hpebley32012-08-02

Thanks for the info.

manuka (author)2012-08-02

It's REALLY  WELL worth while organizing some decent top access for occasional cleaning & draining!  Good work on the project however !

I've had a lot to do with rain water collection here in New Zealand, & mention that leaves, dust, pollen & bird droppings etc WILL eventually end up in the tank. This mixture may block the outlet - I've recently checked a neighbour's enclosed tank that's become blocked so tight that water hardly dribbles out!  The stored water can eventually turn sour, smell & look unsightly too. 

wz-ski (author)2012-08-02

Great project, and i would like to do it :) BUT I have no idea what an IBC is except for your explanation.
Google knows nothing about what it is as a tank.
Could you be more specific... what do the I and B and C stand for?
I live in MA, What state do you find these in?
I was thinking of doing this with a water bed bladder.

bennelson (author)wz-ski2012-08-02

An IBC is an Intermediate Bulk Container.
They are used in a wide range of industries, and are designed to stack and take up one cubic space on a pallet and rack, and easily be moved by forklifts.

It's one of those things which is super-common, but unless you happen you work in a warehouse or some industry that makes use of them, you may have never seen or heard of one.

They are common to find used for sale on Craigslist in most areas of the United States.

I got mine for free from a bottling company, who would rather give them away than throw them out.

smalcolm (author)2012-08-02

I really like this, but I do have a question: have you considered using cheap pantyhose as a filter to keep the pebbles out of the tank?
You should be able to fit it over the tank intake/leaf block with just a little slack to allow some stretch without tearing.

bennelson (author)smalcolm2012-08-02

Ah, excellent!

I have some over my clothes washer drain hose, but I didn't think of it for the rainwater filter. I might have to try that!

f5mando (author)2012-08-02

Superb! Well done job on documenting it while executing the project. My hat is doffed.

TBerryJack (author)2012-08-02

Great job and a really good project as well, I've got a setup something like that. But your project reminds me of the projects around my house, I noticed how you kept using the word "We", "We leveled the ground" "We made a pallet to sit it on" "We did this and we did that" but for the most part it was just dear ole Dad that did everything. It's funny how we Husbands and Dads do most of these things and when the project is done, to hear my family tell it, it's always We did this or that. Maybe I'm wrong it could be that Dad's name is We. haha Great project, more people should do this.

bennelson (author)TBerryJack2012-08-02

It really was a team project. It's just that it's hard for me to do something WHILE running the camera.

Pretty much anything that I did, you didn't get to see, because I was busy doing it, instead of filming it.

Specifically, I did plenty of work locating, transporting, and washing IBCs, cleaning the roof and gutters, building and installing the short collector gutter, running two-hundred feet of hose, and more.

On top of that, I did the photography, videos, video editing and animation, and other documentation.

Doing everything yourself is a lot of work! It's much more fun to work together with friends and/or family.

I will admit that in the videos, it LOOKS like my Dad is just doing all the work in the background!

EcoMotive (author)2012-07-31

Excellent job on this rainwater collection system. I'm planning on building one in the future but unfortunately I have to use several 55 gallon drums. I'd like to point out one thing I would do differently regarding the hose spigot. When I drilled a hole in the 2" sealing cap and inserted the threaded end of the hose spigot into it, I would have used a rubber o-ring and a threaded PVC locknut on the inside of the cap rather than silicone sealant. Keep up the good work!

JMRaphael (author)2012-07-30

This idea is well-implemented and looks like a good alternative to setting up a battery of rain barrels. Keep in mind, depending on your location in the country, this may not be legal. In certain places (Colorado is one such place, I believe), the government owns the water rights for precipitation. I'm not sure if there's a workaround for that; I just thought I would provide that caveat.

dmarsh55 (author)2012-07-31

Ben, y'all will find pretty soon that algae forms. Asap - do a chlorine bleach treatment, then paint that bad boy black - no more algae!

bennelson (author)dmarsh552012-07-31

The tank did distort a bit when full - it just sort of bulged out. Not that it's going to burst or anything, but it doesn't look good.

I think the next thing we will do is box around the tank with wood. That will help the tank keep it's shape, keep out the sunlight, and can be painted to match the barn and chicken coop, so it will look nice too!

Servelan (author)2012-07-31

It's a good idea to use ground-contact pressure treated lumber (a bit different than regular PT), or put down some heavy plastic, and the kind of screws that won't rust, like coated deck screws, if you are putting it on the ground even if you are using its metal cage.

useraaaaa (author)2012-07-31

diy for rain barrel...
step1 - buy rain barrel..

steveharr (author)2012-07-31

Do the tanks have a UV protection coating? Otherwise it won't last too long outside.

Computothought (author)2012-07-30

So cool. Thinking about doing that now.  So want to do hydroponics.

About This Instructable




Bio: Ordinary guy with no special skills, just trying to change the world one backyard invention at a time. See more at: On ... More »
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