Conserve Water by Harvesting Rainwater: How to Make a Rain Barrel

March/April 2007
Once used for making wine and spirits, oak barrels offer Old World charm, though they can be heavy and usually require plugging a too-high bunghole and drilling a new one for your spigot. Try local wineries and distilleries or Kentucky Barrels (

Carol Steinfeld

If you ever worry about your home’s water consumption, take heart: Some of the cleanest mineral- and chlorine-free water arrives free to most homes. Rain barrels are a fabulous, relatively inexpensive and easy way to harness this most basic of nature’s resources.

Rainwater can be used for watering lawns and gardens, filling swimming pools, washing cars and pets, rinsing windows, and even bathing and drinking (if it’s filtered and treated). Using rainwater reduces water costs, takes a load off water supplies and reduces stormwater runoff, helping prevent flooding and erosion. That’s a big environmental bang for your buck.

Rainwater harvesting is catching on across the country. In Texas, people have installed thousands of fiberglass, plastic and galvanized steel cisterns in homes and public facilities to supplement lawn watering (which accounts for as much as 40 percent of home water use). Outside Boston, watershed protection programs promote underground rain-collection tanks that allow big storage capacity under driveways. For indoor use, rainwater usually is pumped, run through a particle filter, and either carbon filtered or disinfected. In Colorado and some other Western states where most water is subject to water-rights laws, the only sure legal way to use rainwater is to water lawns and gardens. All other uses require permission from the state water resources agency. 

Rain Barrel Basics

Unlike water pumped from the ground, rainwater is soft; it contains no minerals that leave calcium scale or residues, no sodium and no chlorine or fluoride. However, it can carry debris, bird excrement and anything else that washes off a roof. During storage, bacteria and insects can proliferate in standing water. Users can manage this easily by topping barrels with screens and using their water supply frequently, which keeps the water moving and aerated.

To store rainwater, rain barrels and cisterns are available in a variety of sizes and shapes. An easy option is a sturdy trash barrel or a food-grade, plastic, 55-gallon barrel available from food importers and processors. Either dip a bucket or watering can in the opening of the barrel or outfit it with a spigot and overflow drain.

Rain Barrels 101

Here’s what you should know about creating and maintaining a rainwater collection system.

• Prevent debris and insects by screening all rain barrel openings. Add a bit of oil or soap to the barrel to make the water surface unsuitable for mosquitoes to lay eggs.

• Reduce rainwater’s mild acidity with 1 teaspoon baking soda per 100 gallons of water.

• The first half-inch of rain, known as the “first flush,” can carry particles and bird excrement. If this is a concern, divert it to the ground, or filter it through a draining container filled with course sand, crushed shell, wood chips or coconut coir mats.

• Rain barrels on the ground provide little water pressure for usage at the same level. If you’re draining your barrel with a spigot, elevate it as much as possible, either with strategic siting above the point of use or with a platform of bricks (water is heavy!). Or use a pump. Place your tap about 2 inches from the bottom of the barrel to maximize pressure but avoid any settled debris.

• Be sure to drain your barrel at regular intervals and before the winter freeze.

• Be sure to include an overflow hose at the barrel’s top or bottom.

How to Make a Rain Barrel


55-gallon drum
11/4 -inch adapter insert MPT (SWP151)
Metal hose clamp (accommodates 1- to 2-inch hoses)
11/4 -inch sump pump hose
(Flotec FP0012-6F) or other hose

Inlet grate:
6-inch NDS Green Grate (or a 4-inch atrium grate or gilled vent insert)
6- to 7-inch metal clamp #10
12-inch-square window screen

Hose bibb/sillcock:
Brass sillcock/hose bibb (3/4- inch MPT)
Silicone sealer or Teflon tape (optional)


1. Cut a hole in the top of the barrel for the inlet drain (use a RotoZip spiral saw, router or large-hole saw). The hole should be only large enough to allow the grate to rest on its flange. Or measure and mark the area to be cut, start a pilot hole, and use a jigsaw. (Or simply glue a piece of screen over a 6-inch hole cut with any tool.)

2. On the side (near the top) of your rain barrel, use a 11/2 -inch keyhole bit to cut a hole to accommodate the 11/4 -inch overflow adapter insert. You may need to rasp or sand the hole somewhat larger to screw in the adapter. Expect a snug fit.

3. Insert the threaded end of the overflow adapter insert into the overflow hole. Keep the adapter straight as you screw it into the barrel.

4. On what will be the front of your rain barrel, use a 15/16 -inch drill bit to cut a hole for the 3/4 -inch hose bibb, about 2 inches from the bottom of the barrel.

5. Insert the threaded hose bibb into the hole from step 4. Keep the hose bibb straight as you screw it into the barrel. You also can apply a bead of silicone caulk or wrap Teflon tape around the bibb before inserting it to ensure a tight,
drip-free connection.

6. Use the metal clamp to firmly attach the window screen to the bottom of the Green Grate. Tighten the clamp with a screwdriver or nut driver. Place the inlet assembly into the barrel.

7. Slide the hose clamp over the barbed section of the adapter insert. Slide one end of the sump pump hose over the adapter and attach firmly with the hose clamp.

8. Attach a garden hose or soaker hose to your hose bibb.

9. Use cinderblocks or similar pavers to elevate the completed rain barrel off the ground to ensure easier access to the hose bibb and to facilitate gravity-fed drainage.

Reprinted with permission from the Montgomery County, Maryland,  Department of Environmental Protection .


Advanced Water Filters
reverse osmosis systems, water filters, water softeners, and replacement filters

Arid Solutions
rain barrels and rain chains

Center for Watershed Protection
online guide to making a rain barrel

Clean Air Gardening
rain barrels and attachments
rain barrels and water accessories

Gardener’s Supply Company
rain barrels and attachments

Master Garden Products
rain barrels and other sustainable garden supplies

Rainwater Recovery Systems
high-capacity rainwater storage

copper rain chains

Further Reading: Rainwater Collection for the Mechanically Challenged (Tank Town, 2006) by Richard Heinichen and Suzy Banks