rain water collection
Our barn’s metal roof is our supply of water for the entire farm

Visitors to the farm are usually surprised to learn that we water the entire garden and landscape with only the water from our rain water collection system. Our system, which collects and stores rainwater from our barn’s metal roof, provides 100% of our annual watering needs. The best part, it was extremely easy to install, and can be inexpensively adapted to almost any home, shed or roof with a gutter.

We spent the past week hooking our tanks back up from winter storage – and within 24 hours  – we had just over 150 gallons stored from a single rain.  It’s been over a year now since we first completed the rain collection system – and I honestly don’t know how we survived without it.

It gives us access to free water, and with our two plastic tote tanks, can collect as much as 550 gallons from a single downpour.  And that’s only using rain from the back portion of the roof!  This spring, we will add a third tank fed by the front gutter – increasing our storage to just shy of 900 total gallons – enough to handle our watering needs for nearly two months of complete drought.

Our Rain Water Collection System – How It Works:

 rain water collection
Through a simple in-line diverter – the rainwater is carried to our main capture tank

The system collects rain water from a simple adapter made to fit our existing barn’s gutter. The barn has a standard gabled metal roof measuring 13 wide’  x 32′ long on each side.  A  32′ section of guttering runs along the bottom of each side of the metal roof, slanted slightly to carry all of the water to the eastern side of the barn.   From there, both sides empty into standard downspouts.

The front downspout (not used currently), runs down and out to the field for normal drainage. On the back downspout however, we installed a simple 2-way in-line diverter (See Picture). When the metal lever is slid to the left, rain water is diverted into a 275 gallon storage tank located below the downspout. When all tanks are full, the switch can be slid back for normal drainage.

 rain water collection
This is from one single rain last week – about 125 gallons

From the main storage tank, we pump and fill a second 275 gallon tank installed above our garden. With that, we can water all of our plants quickly, using gravity and a standard garden hose connected to the tank.

To increase capacity and mobility, we are adding a second diverter to the front gutter this year.  That will fill a 3rd tank mounted on wheels – giving us the ability to pull water anywhere it’s needed with our tractor.  That will be a huge time saver when it comes time to water the newly planted grapevines and fruit trees on the hill this year.

Here is a look at the system’s components and cost:

rain water collection
The water then empties into our main storage tank

Totes: $40 each  We found ours for $40 each after searching on Craigslist.  You can also check with local food plants that may receive their raw materials in them.  One word of caution – make sure you know what was originally in your tanks and that it is safe.  Our tanks were used to hold maple syrup and molasses – simple food products that can be cleaned out and re-used.  You will want to avoid using tanks that held harsh chemicals. Most tanks come with a 6″ threaded cap on top, and a 2″ threaded outlet valve at the bottom.  You can convert the bottom 2″ valve to accept a standard garden hose with a few adapters found at your local hardware store.

Diverter Switch :  $15  You can find standard gutter diverters at your local home improvement store for about $15 – they install in minutes with rivets or screws.

rain water collection
We connect a standard garden hose to the tanks with a simple threaded adapter

Threaded Valve and Hose Adapter: $15 Your local plumbing or hardware store can hook you up with a simple threaded connection valve to convert the 2″ drain at the bottom of your tank to handle a regular garden hose.  We also installed a ball valve ($10) on our tank for an extra shut off point.

A couple of final notes on collecting and using rainwater:

Keep It Dark:  You will want to keep the water from getting direct sunlight to keep algae from growing in the stagnant water. Algae can only grow if there is light.  If your tank is translucent like ours, you will want to cover it.  We use a black covering like a grill cover to cover them up once the sun and algae become a problem. Not only does it dress it up, but it keeps the water and the flow line crystal clear.  For the pictures here, we have the covers off to show the tanks.

Keep It Covered: No matter what system you use to store your water, you will want to keep closed.  Water that sits is an open invitation to mosquito larvae .  Our totes came with 6″ caps and lids on the top.  We simply cut out the hole for the downspout, and then sealed the edge with some inexpensive foam.

Know What To Use The Water For:  We only use our reclaimed water for watering plants or washing off equipment ,etc.  Since we do not treat it in any way, we do not use it for drinking.

Check to make sure your allowed to collect rain water.  Although it sounds crazy, in some states out west you are not allowed to collect rain water, as the water rights still belong to the state.  So to be on the safe side, check with your local or state government to make sure it’s legal where you live.

Happy Gardening!! – Jim and Mary

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46 thoughts on “Creating A Simple And Inexpensive Rain Water Collection System

  • April 10, 2014 at 9:16 am

    How do you actually water your plants from the totes? Do you water every plant individually? Or do you have a drip irrigation system installed?
    must take awhile if you water every plant one at a time.

  • April 3, 2014 at 3:59 pm

    Wow so glad I came across your site, you guys have awesome ideas and i love all the tips. Keep up the good work.

  • November 7, 2013 at 9:32 am

    I did not have sufficient pressure to use the water when I tried this. Do you need a pump of some kind? I did have problems with the adaptor from the tank leaking,but I still thought the pressure would be greater.

    • February 20, 2014 at 5:36 am

      Look on youtube there is a solar powered pump there

  • November 7, 2013 at 9:25 am

    Can you post a pic of the cover or tell more about it? We have the same set-up but really struggled with the algae this summer. We thought about spray painting the container black with plastic spray paint, do you think that would work also? We use the water for our animals, so I’m a little nervous about not being able to see it.

    • November 7, 2013 at 12:17 pm

      I need to get a pic of that so I can post – and when i do i will forward to you. To explain it – it’s just a piece of large grill cover material that we made to fit over and keep dark. You can also take the screws out of the tank holder and paint the entire plastic piece black on the outside to have the same effect.

  • October 29, 2013 at 4:57 am

    yes , this is very inexpensive . this is really usefull for us.

  • May 30, 2013 at 9:29 am

    Can you go into more detail about the adapters you use to hook your tank to the hose. I’ve had real trouble finding good things to use for cheap.

    • May 30, 2013 at 11:22 am

      Nathan – I used a 2″ male adapter and then a couple of reducers to get it down to the standard garden hose fitting. I want to say it cost about $10 in total to do it.

  • May 11, 2013 at 2:22 pm

    We have a 1,000 gallon water tank collecting only the water from our carport. We made it through a very dry summer last summer without watering our garden using city water.

    State laws against rainwater harvesting seem counter-productive to me. I can’t catch rainwater to water my garden, but it’s okay to water it using treated potable water that I pay for? Sounds like it is the money talking not logic.

  • April 28, 2013 at 3:00 pm

    My wife and I just purchased 2 of these same tanks today from a person that used them for maple syrup harvesting..We have the same intent for water collection. Our barn style garage is 40×28 and has the 2 angled sloped roof,like a barn. Its shingled though, so I’ll have to add a filter of sorts. We have rain gutter along the front side and need to add some along the rear, then hook it up into the tanks..We have 2 gardens and 6 fruit trees we intend to keep watered here in sw NY..

    • April 29, 2013 at 8:16 am

      Sounds like you will have a great set-up! You will get quite a bit of rain collected from that size roof and it should work great! – Jim

  • April 19, 2013 at 8:43 pm

    Anyone who collects rainwater needs to have some kind of screening to cover any opening the water will enter through. Mosquitos will lay eggs even through the screen, BUT the hatched Mosquitos cannot get back out.
    All the information about this rainwater collecting system has been great!

  • April 3, 2013 at 7:10 pm

    Really cool! I’m going to do the same thing, but with 55 gallon drums.
    How do you pump from the main container to the secondary one in the garden? What equipment do you need? I didn’t see that part in the instructions.

    Thanks so much!!

    • April 4, 2013 at 3:13 pm

      We can pump it up with a regular water pump – or now, we can actually take up the one tote on the trailer and skip that step. The mobile tank will really help us a lot this year! Jim

  • March 28, 2013 at 10:18 am

    Love it! We are trying to rig up something like this that ties into our septic system so instead of spraying, it collect for watering the garden. This will help.

  • March 28, 2013 at 12:54 am

    This is really cool. Thanks for sharing. I’ll have to forward it on to my people who do this kind of work (aka my husband πŸ˜‰

  • March 21, 2013 at 1:18 am

    That is amazing and something I’ll want to use when I start my new garden. Do you guys do anything to filtrate the rain water for drinking? Or do you not recommend drinking it at all because it’s contaminated from geoengineering (chemtrails)?

  • March 20, 2013 at 10:18 pm

    How long do you expect the plastic to last on those containers? I have seen them around…though not at that price, but have been concerned about getting a crack from UV damage.

  • March 18, 2013 at 5:55 pm

    We have a rain water collection system as well, just the last three years. I think that it was purchased at Lowes. We have it up on a frame that is about three feet high so that the water can flow out by gravity. There is also a build in overflow hose. The downspout just flows onto the top of the big tank and the water flows across the top, but most of the water goes through a screened hole in the top. I think it holds about 50 gallons. It fills easily in a moderate rain. I use the attached hose to fill my watering can. I’m not sure it would work to use a hose to go much of a distance to water larger beds. How do you get the water to your gardens with your system? Our tank, etc. is put away for the long winter. Building the stand and rearranging the gutters and downspout make this system a bit of a bother to set up initially.

  • March 18, 2013 at 4:36 pm

    I’m so happy to have found this post (via Hometalk on FB)! Reblogging on Pajari Girls now. Can you tell me more about how to figure out what size pump I’ll need? We have one tote already. Thanks!

  • March 18, 2013 at 11:56 am

    I’m visiting from the Homestead Barn Hop. This is just what we’ve been considering. Until we get our well drilled, this will provide enough water for the new garden. Thank you for the helpful info πŸ™‚

    • March 18, 2013 at 2:57 pm

      It sounds like it will work perfect for you! It has been a lifesaver for us! We are glad you stopped by the blog!

  • March 18, 2013 at 10:16 am

    Hi Jimmy and Mary
    I ‘ve seen your system and am impressed! I’m thinking about using our garage roof to collect the rain water and putting the tank on the north side so it won’t get sun. I’ll let you know how things go. By the way, should I be planting that rye or whatever you said to plant in the garden to enrich it before putting the plants in the garden at this time? Where can I get some? It is really wet after all the moisture we have been getting lately. Looking forward to a great growing year!

    • March 18, 2013 at 10:19 am

      Hey there Carly! I would say yes to the annual rye for a green manure crop – if it ever stops being winter!!! πŸ™‚ The tank would work great there on your north side – and if you want – I might have an extra for you! I also have plenty of Rye if you need it – I can bring some down this week. Jim

  • March 18, 2013 at 1:22 am

    Love this idea! Sadly I live in one of those states out west where it is illegal to collect rain water, even on your own property. I had no idea such a law existed until a few years back when there was a news story about a poor soul who was convicted of collecting rain water at their home.

    • March 18, 2013 at 2:55 pm

      Kristi – It seems so counterproductive to not allow the conservation of rainwater – and how sad they convicted someone of it!

    • March 20, 2013 at 6:57 pm

      It is unbelievable that any state where water is at a premium would restrict rainwater harvesting. Master Gardeners throughout Texas sponsor classes for the public on collecting. I was a part of that program until we moved out of state in November.
      Think about what happens to the rain thal falls on impermeable surfaces or on lawns and washes all sorts of contaminants into the storm drains to go into our streams, rivers and oceans, or is first collected, treated and recycled as potable water.

    • March 20, 2013 at 10:06 pm

      I’ve read a bit about so called rain water gardens. This is where the downspout water goes into a combination garden, small pond on the lawn to slow the passage of the water, rather than having the rush of water reach the sidewalks, streets and gutters. The point is, apparently, to get more of the water back into the ground water system. Perhaps the laws against water collection come about because in some areas, more water is harvested than goes back into the ground water, especially in areas where extensive irrigation is used. Much of water that is used for irrigation, if it is sprayed on the fields, actually evaporates, so it doesn’t help either the plants or the ground.

      • March 21, 2013 at 12:15 am

        LoieJ (the other one), your comment on the evaporation of sprayed irrigation water is correct. 50% or more can be lost to evaporation. The rain garden does more than slow the movement of rainwater. It contains grasses and other plants which have roots that filter and purify water as it percolates back into ground water. I can’t wait to install one in my yard.

    • May 13, 2013 at 1:00 am

      Oh my! I have never heard of such a thing!! How can they do this? I’d be on my legislators constantly. THats insanity!

      • May 13, 2013 at 8:27 am

        It is crazy. You are not keeping the water from going into the ground, only delaying it so that you can water when there is no rain.

    • August 3, 2013 at 12:42 pm

      actually there is more to it than just collecting rain water – he used it to fill 3 ponds, one of which was stocked with fish, IIRC… I’d encourage you to look into the law itself & see if it prohibits rain barrels. πŸ™‚

  • March 18, 2013 at 1:22 am

    No question is too silly, right? We’re city dwellers, and have a shingle roof on both our house and garage. Can this type of material be used for reclaiming rain water?

    • March 18, 2013 at 2:54 pm

      Not a silly question at all. Metal roofs are obviously the best – simply because they tend to be the cleanest, with no residues to fall off. Shingle roof’s can be used – but I have heard of people installing a filter to remove the bits and pieces of asphalt and grit that can come off. Jim

      • March 19, 2013 at 6:53 am

        My filter is knee high panty hose I get on sale at Walgreens for $.49. Put one on the end of the downspout going into your tank and it’ll collect all the debris. You need to take off and rinse off inside out periodically, especially in Spring. I’ve also put a big piece of screening over my tank and then pushed downspout (no hose on this) down into tank. Rinse this off periodically. Works for me and cheap!

  • March 17, 2013 at 9:59 pm

    Shared this with some friends working on a school project in Guelph, Ontario. Really great article. Thanks for sharing

  • March 17, 2013 at 4:15 pm

    I’ve seen those tanks on Craig’s List too! Great system. I hope you will do another feature showing how you water the garden with the gravity-fed system. (picture #7) We use 3 rain barrels now, but when we have acreage, I think this would be a great set-up! Love that you’re reclaiming water that nature provides!

    • March 18, 2013 at 2:40 pm

      Thanks Daisy – We will be sure to do one this summer for the garden watering!

  • March 17, 2013 at 12:09 pm

    What is the lowest temperature that a filled tank like this can take without damage?

    • March 17, 2013 at 2:33 pm

      Dave – Not sure about the lowest – but we have never had a problem having it outside when the temperature drops down in the 20’s overnight. We take them down in the winter to avoid hard freezing and refreezing, but in the the early spring they have always been okay.

  • March 17, 2013 at 8:36 am

    A couple places in your blog didn’t come out right. What do you use to keep the tank out of sunlight? Right now I’ve got mine in the barn with doors shut but might want to add some outside too. Aren’t you afraid some frosts might freeze up lines yet? Seems kind of early but I’m in central IL. I think I’m going to wait a couple more weeks since I don’t have anything to water anyway. Thanks for telling us how you do it!

    • March 17, 2013 at 8:48 am

      Hi Pam, I should have said that we have not yet covered them this year after just getting them up. We use a black water-proof material (like a grill cover) to keep light out. There was just no need to put them over it yet so early in the year. As for frosts – once it gets past March here, we really do not get the deep freezes that would worry about the lines. We needed them up early this year because I needed to pour some concrete for the new coop and needed water :).

    • March 20, 2013 at 6:24 pm

      A very simple way to keep sunlight/algae out of the rain barrel is to paint it. It can be made beautiful by painting all sorts of designs on it. Check your local paint stores for paints that will adhere and not be toxic to your garden.

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