A Quick Guide To Rainwater Harvesting

What Is Rainwater

rain-water-harvestingRainwater harvesting is the collecting and storing of rainwater. You can collect rainwater from a roof, which is the most common method, and store it in catch-ment tanks, such as rain barrels.

A Brief History of Rainwater Harvesting

Before there were public water utilities, many American households harvested rainwater. With the development of large, reliable water treatment and
distribution systems, the appeal of rainwater harvesting diminished. However, as the environmental and economic costs of providing centralized water escalate, a new interest in rainwater harvesting has emerged.

The easiest way to begin harvesting rainwater for your home is to use a rain barrel to collect water for your container plants, landscape, and garden
Some cities and counties offer rebates or reduced costs for rain barrels. Check with your local government or water utility to find out if incentives are available in your area.

Reasons for Harvesting Rainwater

  • Benefits
  • The water is free.
  • Rainwater is better for plants than chemically treated water.
  • Rainwater harvesting can help reduce flow to storm water drains and reduce stream pollution.
  • Using stored rainwater can reduce utility bills.


55-gallon polyethylene plastic barrel
3/4-inch hose spigot
3/4-inch PVC closed nipple
window screen
Teflon cement
water hose (optional)
bricks or concrete blocks (optional)

drill with a 1-inch paddle bit
utility knife or jig saw


1. Inflow. Use the utility knife or jig saw to cut a hole in the top of the barrel approximately the same diameter as your gutter downspout.

2. Spigot. Measure 3 to 4 inches from the bottom of the barrel and drill a 1-inch hole. Screw the spigot halfway into the barrel, apply some Teflon cement to the exposed threads, and continue to twist until tight. In addition, you can use a rubber washer, metal washer, and a lock nut to more firmly secure the spigot to the barrel from the interior.

3. Overflow. Measure 3 to 4 inches from the top of the barrel and drill a 1-inch hole.Twist in the 3/4-inch PVC closed nipple about one-quarter of the way, apply Teflon cement to the exposed threads in the middle portion of the coupling, and continue to screw it in, leaving 1 inch of thread exposed.

Connect the hose to the pipe coupling overflow spigot at the top of the barrel. You can run this hose into another barrel or to a soaker hose (which will evenly distribute excess water and help avoid flooding).

4. Downspout. Place the barrel directly below the downspout. You will need to reconfigure the downspout to flow into the hole. If you like, place the barrel on concrete blocks or bricks. Raising the barrel will allow you to get a bucket under the spigot, and will facilitate leveling the area where your barrel will sit. Cover the hole on the top of the barrel with the window screen, to prevent sticks, rocks, or dirt from getting into it. Screens also keep mosquitoes out. Secure the screen with a few bricks or rocks to keep it in place

Some cities and counties offer rebates or reduced costs for rain barrels. Check with your local government or water utility to find out if incentives are available in your area.


Like most things around your home, your rain barrel needs a little regular attention to keep working smoothly.
To keep it in the best shape:

  • Use all the water in the barrel regularly.
  • Clean your gutters at least twice a year to reduce debris.
  • Once a year, during a dry spell, tip the barrel over and rinse it out with a hose.
  • Any standing water will begin to smell after a while, especially if it contains organic matter, such as leaves.

Smelly water won’t hurt your plants, but it can be a nuisance. To avoid it:

  • Use all the water in the barrel within a month of collecting it.
  • Put a capful of chlorine bleach into the water. This small amount won’t hurt plants.

A well-sealed screen will help keep mosquitoes from getting into your rain barrel. However, mosquito larvae may still wash in from your gutters. You can help prevent mosquitoes from breeding and keep them at bay by emptying the barrel regularly. You can also add mosquito dunks to the water. These dunks contain a nontoxic bacterium that kills mosquito larvae. It’s safe for your plants, and it will not harm pets or people. You can find this product at most garden-supply stores.

The Next Steps

Remember that the water collected in a rain barrel as described in this publication is intended to be used for outside purposes only, such as watering your container plants, landscape, and garden

  • If you decide that you want to store even more rainwater, you can connect two or more rain barrels.
  • To safeguard the quality of your drinking water, never submerge a water hose in a rain barrel.
  • To collect rainwater for extensive landscape use, you can install larger systems using cisterns.


  • Check your faucets and fix any leaks you might have.
  • Wait until you have a full load of laundry before washing, or use a lower water-level setting.
  • Avoid over-watering your lawn. When needed, water 1 inch, once a week. To water only 1 inch, place a 6-ounce tuna can on your lawn and stop watering when it is full.
  • Invest in water-efficient plumbing fixtures. Replacing an older toilet with a water-efficient model can save up to 4,000 gallons of water a year. Installing a faucet aerator can cut water consumption in half. For additional information on water-efficient products, visit the Environmental Protection Agency’s WaterSense website, at <>.

Related Video  (How to Build a Rain Barrel)

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