How To Build A Rainwater Collection System

Why choose wikiHow?
When you see the green expert checkmark on a wikiHow article, you know that the article has received careful review by a qualified expert. If you are on a medical article, that means that an actual doctor, nurse or other medical professional from our medical review board reviewed and approved it. Similarly, veterinarians review our pet articles, lawyers review our legal articles, and other experts review articles based on their specific areas of expertise.

How to Build a Rainwater Collection System

Four Parts:

Did you know the average roof collects 600 gallons (2,271.2 L) of water for every inch of rainfall? Don't let all that water go to waste! You can make a rainwater collection system for under a hundred dollars and store hundreds of gallons of water to use for your garden or other purposes. Read on to learn how to prepare your water storage unit and start collecting rainwater.


Getting Rain Barrel Supplies

  1. Obtain one or more water storage barrels.You can buy a water storage barrel online, but it's cheaper to get a used one from a company that uses large barrels to store food and other merchandise (just be sure to clean it thoroughly with soapy water). A rain barrel can also be made from a large plastic trash can. Get a barrel that will hold 30 to 55 gallons (113.6 to 208.2 L) of water.
    • If you decide to get a used barrel, make sure that it didn't formerly contain oil, pesticides, or any other type of toxic substance. It's too difficult to clean these chemicals from the inside of the barrel, so using them is too risky.
    • If you plan on collecting a lot of water, get two or three barrels. You'll be able to connect them so they're all part of the same water collection system, and this way you can have hundreds of gallons of water at your disposal.
  2. Get additional supplies to turn the barrels into a water collection system.The supplies you'll need to make your rainwater collection system can easily be picked up at a hardware or home and garden store. Figure out what you already have on hand, then gather the following supplies:
    • 1 standard 1-inch hose spigot with ¾-in. pipe threads, so you can access water from your rain barrel.
    • 1 ¾-inch x ¾-inch coupling
    • 1 ¾-inch x ¾-inch bushing
    • 1 ¾-inch pipe thread with a 1-inch hose adapter
    • 1 ¾-inch lock nut
    • 4 metal washers
    • 1 roll Teflon thread tape
    • 1 tube silicon caulk
    • 1 “S”-shaped aluminum downspout elbow, to direct water from your downspout to your rain barrel
    • 1 piece of aluminum window screen, to keep leaves, bugs and other materials out of your water
    • 4-6 concrete blocks

Building a Rain Barrel Platform

  1. Level an area right next to your downspout.The downspout is the metal or plastic tube running from your roof's gutters to the ground. You're going to reroute the downspout directly into your rain barrel, so you'll need to prepare a platform in the area right next to it. Clear away any rocks and other debris from the area. If the ground there isn't flat, take a shovel and clear away enough dirt to flatten an area large enough to accommodate the number of barrels you have.
    • If your downspout empties out onto a concrete driveway or patio that's situated on a hill, build a level surface by stacking a few plywood boards in the low section so you've got a level area on which to set the barrels.
    • If you have more than one downspout on your home, choose to place the barrels near the one that's closest to your garden, so the water you collect won't have as far to travel when it's time to use it.
  2. Create a layer of pea gravel.This will provide better drainage around the rain barrels and help keep water away from the foundation of your home. Dig a 5-inch deep rectangle in the area you leveled to accommodate the rain barrels, and fill it with inch (1.3 cm) of pea gravel.
    • Skip this if your downspout empties onto a concrete driveway or patio.
  3. Stack concrete blocks on top of the pea gravel.Stack them sideways to create a raised platform for the rain barrel or barrels. The finished platform should be wide and long enough to hold all of your rain barrels level with each other, and steady enough that they won't tip over.

Adding the Spigot and Overflow Valve

  1. Drill a spigot hole in the side of your barrel.It should be high enough up on the barrel to fit a bucket or water jug underneath. Make a 3/4-inch hole to properly fit the spigot you bought.
    • This is the standard size for a spigot; if you're using a different sized-spigot, make sure you drill the right sized hole so that it fits into the side of the barrel.
  2. Squeeze a circle of caulk around the hole.Put caulk on both the inside and the outside of the barrel.
  3. Attach the spigot.Put the spigot and the coupling together. Use Teflon tape to wrap the threaded ends to create a tight seal and prevent leakage. Put a washer on the threaded end of the coupling and insert it through the hole in the barrel from the outside. Slip another washer over the pipe from the inside. Attach the bushing to hold the spigot in place.
    • Follow the directions for attaching the type of spigot you have. You may need to attach it differently than specified here.
  4. Make an overflow valve.Drill a second hole a few inches from the top of the barrel. It should be inch (1.9 cm), or the same size as the first hole you drilled. Squeeze a circle of caulk around the hole, both inside and outside the barrel. Slip a washer on the hose adapter and put it through the hole from the outside. Put another washer on the inside threads, attach some Teflon tape, and attach a nut to tighten the assembly. You can attach a garden hose directly to the valve.
    • If you have a second barrel to use as an overflow barrel, you'll need to drill a third hold in the first barrel. Drill it at the same level as the spigot several inches to the side. Then drill a inch (1.9 cm)-hole in the second barrel at the same level as the hole you just drilled in the first one. Attach hose adapters to the holes in both barrels as described above.
    • If you're using a third overflow barrel, the second barrel will need a second hole so you can connect it to the third barrel. Make a second valve on the opposite side of the barrel at the same level. Make a valve in the third barrel as well.

Assembling the Collection System

  1. Connect the downspout elbow to the downspout.Figure out where to connect it by setting the barrel on the platform next to the downspout. It should be close enough to the downspout that you can connect it with the downspout elbow. Mark the downspout one inch below the height of the rain barrel. You'll need to attach the downspout elbow to the downspout so water will pour directly into the barrel. Use a hacksaw to cut the downspout at the mark. Fit the elbow to the downspout. Fasten it in place with screws, and make sure they're tight.
    • As your measuring and fitting the elbow to the downspout, make sure that the end of the elbow will dip well into the barrel so all the water gets collected there. You don't want the water to be pouring into the barrel from above.
  2. Connect the barrel to the elbow.If the barrel has a lid, use the hacksaw to cut a hole large enough for the end of the elbow to fit inside. Cover the area around the hole with the metal screen.
  3. Place a filter at the top of the downspout.This will prevent leaves and other debris from running down the downspout and creating a clog in your rainwater collection system.
  4. Connect the additional barrels.If you have more barrels, set them on the platform and connect lengths of hose to the valves.

Community Q&A

  • Question
    How can I take down a rainwater catcher?

    Professional Landscaper
    Anthony "TC" Williams is a Professional Landscaper in Idaho. He is the President and Founder of Aqua Conservation Landscape & Irrigation, an Idaho Registered Landscape Business Entity.
    Professional Landscaper
    Expert Answer
    In order to take down a rain water catcher, you will need to disassemble it first.
  • Question
    Can I catch rainwater without using the gutters?

    Professional Landscaper
    Anthony "TC" Williams is a Professional Landscaper in Idaho. He is the President and Founder of Aqua Conservation Landscape & Irrigation, an Idaho Registered Landscape Business Entity.
    Professional Landscaper
    Expert Answer
    You may have to if the downspout needs to be changed or relocated to accommodate Your storage location.
  • Question
    How can I move water from down to up through a motor?
    wikiHow Contributor
    Community Answer
    You can install a submersible pump inside the tank and run the water line out near the top of the tank adjacent to the overflow. This will require electrical work. Or if you have an external pump already, you could simply run the intake line into the barrel and let the pump suck it it out. Consider installing a filter in-line before the pump on any application as well as a screen over the rainwater collection hole. Also check to see what size pump motor is needed to push your water where it needs go at the rate you wish it to flow and the pump electrical requirements.
  • Question
    How do I connect two rainwater collection systems?
    robert bailey
    Community Answer
    For a temporary connection that can easily be converted back to two independent systems, you can install a secondary spigot near the top on each system and use a garden hose connecting the two spigots. The normally 'male' end of the hose needs a 'female' adapter to attach to the spigot. Water will then flow from the higher system to the lower once the higher system is full. For a more permanent connection, replace the spigots with PVC fittings like the kind used for the overflow drain and use appropriately sized PVC pipe in place of a hose. Be sure to support the pipe to prevent it from pulling out of the barrels over time.
  • Question
    Can I do this without cutting into my gutters?
    wikiHow Contributor
    Community Answer
    Yes. Use a large funnel or shape metal into the shape of a funnel and place at the top to collect water.
  • Question
    How long will it take to make this collector?
    robert bailey
    Community Answer
    Once you have all of your materials (lumber, barrels, pipe fittings, etc.) on hand and a clear plan, it can easily be done in one to two weekends. Constructing an elevated stand from wood to provide the system with a minimum amount of water pressure for the actual collection system itself will be the longest task. If you are simply going to raise the barrels up using concrete block, that will be much faster. The plumbing portion is pretty quick and easy. Site leveling and preparation with pea gravel takes little time.
  • Question
    Is this useful for any other purpose?
    wikiHow Contributor
    Community Answer
    No. The only use of a rainwater collection system is to collect rain water.
  • Question
    I want to use this system but make the water run inside the building and have the cans inside - how can I do that?
    wikiHow Contributor
    Community Answer
    You could simply install a small hole in the bottom of your collection cans outside and a hole in the side of the house, with a pipe connecting the outdoor cans to an indoor trough or something. You can find branching extensions for the end of the pipe so that you can then branch off multiple small pipes for multiple indoor cans.
  • Question
    What are some ways I can harvest rainwater?
    wikiHow Contributor
    Community Answer
    You can set up a large trough outside next to your house to collect water. You can run the gutter system into the trough, or you can run it into various barrels or cans to keep it for different purposes.
  • Question
    Can I do anything in order to be able to use the system in winter, e.g., insulation/heating/indoor water storage?
    robert bailey
    Community Answer
    If you experience temperatures below freezing, it is advisable to drain and leave open any spigots on your system for the winter. Water in any lines connecting multiple barrels will freeze fairly quickly and will likely compromise the system by cracking or pulling loose from the barrels. Rainwater harvested prior to winter can be stored in separate storage containers in a garage, provided the temperature in the garage does not drop below freezing for a length of time that would allow for that water to freeze. There certainly are ways to keep that water insulated and/or warm using artificial means, but are beyond the intended scope of this article's instructions.
Unanswered Questions
  • The gutter I want to use collects pine needles? Will this taint water for watering flowers/plants?
  • How do I attach plastic pipe fittings to the barrel, when I cannot access the inside of the barrel?
  • I have ducks housed in an open field. Can I collect rain water in the field and provide it to them to drink?
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.


Quick Summary

Building a rainwater collection system involves using a S-bend aluminum downspout to connect your gutter to a large barrel. There is usually a filter in the downspout to keep leaves and other debris out of the barrel, and there should be an overflow spout near the top of the barrel to prevent the downspout from backing up if the barrel is completely filled. That means the barrel needs to be on level, well-draining soil to keep the lost moisture away from your house. A spigot is put on the bottom of the barrel to retrieve the water.

Did this summary help you?
  • You can keep the debris out of your gutters with screen over the gutter or the commercially available gutter "louvers" which send the debris over the edge of the roof while allowing the water to enter the gutter.
  • Rainwater should not be used for drinking long-term, even if filtered or treated, as it is in fact, distilled water without minerals and can cause mineral deficiencies after long-term consumption.
  • Check for free buckets and drums online at , or ask at local hardware stores, car washes, stables, farms etc.
  • Be sure to check your local codes and ordinances regarding rainwater collection.
  • This water is not suitable for human consumption straight from the spigot; however, it is the same water that was washing onto the lawn prior to the addition of the collection system. If you wish to make the water potable, boil the water vigorously for 1 to 3 minutes (depending on your altitude) to kill bacteria, parasites, and viruses. After cooling to room temperature, pour the boiled water into a filtered water pitcher (typical brand names are Brita, Culligan, and Pur) with a fresh filter. Depending on the pitcher, this will reduce most heavy metals, chemicals, and other contaminants to safe levels for temporary use. You may also choose to use a steam distiller to purify the water for drinking and cooking purposes. Steam distillation removes more impurities than filters.
  • Keep your gutters free from debris, particularly maple tree seeds. These can easily overwhelm the best strainers.
  • Plastic downspout fittings are extremely durable.


  • Water collected from some rooftops will also contain chemical components from the composition roofing.
  • Do not drink rainwater without treating it first (see above), but the water can be directly used to water plants, wash things, for bathrooms, etc.
  • Many parts of the earth receive 'acid rain.' The rainwater combines with sulfur compounds that come from burned coal and form sulfuric acid. This is a global phenomenon. The pH of the rainfall rises after the first five minutes of a downpour, and the molarity of the acidic water is fairly low.
  • Check the legality of doing this with your local city officials, as it is illegal in some areas to collect and hold any kind of water for re-use.

Related wikiHows

Sources and Citations

  • Videos provided by

Made Recently

Add a photo
Upload error
Awesome picture! Tell us more about it?

Article Info

Featured Article

Categories: |

In other languages:

Español: , Italiano: , Deutsch: , Português: , Русский: , Français: , Bahasa Indonesia: , العربية: 

Thanks to all authors for creating a page that has been read 1,043,715 times.

Video: How To Build A Rainwater Collection System

How to Build a Rainwater Collection System
How to Build a Rainwater Collection System images

2019 year
2019 year - How to Build a Rainwater Collection System pictures

How to Build a Rainwater Collection System forecast
How to Build a Rainwater Collection System forecast photo

How to Build a Rainwater Collection System pics
How to Build a Rainwater Collection System pics

How to Build a Rainwater Collection System How to Build a Rainwater Collection System new pics
How to Build a Rainwater Collection System new pictures

picture How to Build a Rainwater Collection System
pics How to Build a Rainwater Collection System

Watch How to Build a Rainwater Collection System video
Watch How to Build a Rainwater Collection System video

Communication on this topic: How to Build a Rainwater Collection System, how-to-build-a-rainwater-collection-system/
Forum on this topic: How to Build a Rainwater Collection System, how-to-build-a-rainwater-collection-system/ , how-to-build-a-rainwater-collection-system/

Related News

20 Reasons to Lose 20 Pounds By Summer
How to Manage an Organic Chicken Farm
Waymo and Mothers Against Drunk Driving team up
How to Cancel a Real Estate Contract
Stance Socks
Wade Logan Durbin 4 Piece Sectional Set with Cushions WDLN2865 Cushion Color: Sunbrella Silver
Summer six-pack challenge: Lift and sprint
How to Keep a Healthy Thyroid
6 Ways to Cover and Conceal Psoriasis
Free Perfume Samples

Date: 12.12.2018, 17:03 / Views: 73155