Rain Barrel Info

What is a rain barrel?

For the most part, a “rain barrel” can be any container used for the controlled capture, storage and discharge of rain water that otherwise would flow off a roof, through gutters and downspouts/rain chains and become runoff.

The typical rain barrel “technology” design ranges from fairly rudimentary to advanced cleantech but generally divides between one of two types of design:

  • OEM or Original Equipment Manufactured: a pre-made rain barrel specifically designed and generally constructed of plastic, metal, fiberglass or, less likely, wood which are designed specifically for downspout runoff capture with any combination of the following features: downspout diverter, seasonal by-pass, first flush or in-line filtration, one or more drain ports with dedicated valves, passive or active siphon overflow to a dedicated discharge line for either surface or underground infiltration, and including other much less generally common features: linkage kits, pumps, actuated valves, passive or active level measurement, in/outflow measurement, low-water potable make up, pressure reduction valves, anti-freeze heating, or sewage connections;
  • DIY or Make & Take: units largely constructed from repurposed containers (syrup drum, wine barrel, etc.) modified individually or by a central entity (such as local municipality or water bureau) with kits or general parts from a hardware store. Like their OEM cousins, these devices are intended to capture and discharge rain runoff.

Among the public policy purposes attributable to residential and other small lot rain harvesting are three primary trends broadly associated with what is commonly referred to as “green infrastructure”:

  • Low impact design to reduce surface runoff from lots into the sewer system, helping to limit pollution runoff and eliminate combined sewer overflows into our rivers and streams;
  • Conservation offset of piped or well-based potable water supplies through groundwater recharge; and
  • A primary source of water for non-potable applications.

Individual property-based applications of rain harvesting are largely concerned with above-ground, discrete units capturing roof runoff from downspout, rain chain or other runoff control features. The other typical methods of rain harvesting – subsurface cisterns and rain gardens – are not currently included in the Registry.

Rain barrels come in a wide variety of materials (plastic and wood are the most common), designs, and colors.

Note:  1-inch of rain will produce approximately 600 gallons of runoff from 1,000 square feet of roof surface area. It’s common for about 1/8-inch of rain to fall each hour during a moderate rainstorm, which draining a 1000 square foot roof would fill a 55-gallon rain barrel in about 45 minutes.

Size your rain barrel to your roof: measure the length and width of the portion of your roof that drains to the downspout where you place your rain barrel. If possible, install enough capacity, either through one or multiple connected barrels, to capture all rainfall runoff.

Using rain barrels in conjunction with other Best management Practices (BMPs), including rain gardens, recessed lawns, vegetated swales, and vegetated filter strips, will greatly enhance your home’s stormwater management capabilities. These BMPs are useful particularly for rainfall events that exceed the capacity of the barrels.

What should I do with the rainwater I can’t collect?

A typical rain barrel will capture only a fraction of roof runoff during a rain event, so be sure to include an option for overflow into your plan.  Some rain barrels are set up to divert excess water into another rain barrel or back into the storm drain once they are full.  Another option is to send your overflow into your yard making sure that it drains away from your home’s foundation to a safe discharge location. Rain gardens are also becoming a popular way to incorporate rainwater runoff into your landscape.

How can you use your collected rain water?

Water captured in rain barrels is typically used for outdoor irrigation and non-potable purposes. Do not use water from your rain barrel for drinking water! Typically no permit is required for irrigation use; however, be sure to check local codes and ordinances on the use of rain barrels before you do any disconnections or alterations to your property.

Some common uses include:

1. Water flowers, trees, shrubs and gardens (note-depending on the composition of your roofing material, your water from a rain barrel may not be suitable for use on edible plants such as vegetables, fruits or herbs.)

2. Cooling compost or rinsing out your compost bucket

3. Washing machine (check local ordinances)

4. Indoor plants

5. Lawn

6. Wash your pet

7. Wash your vehicle on your lawn or gravel

8. Wash your hands, tools or muddy boots

9. Flushing your toilet

10. Mixing cement

11. Cool yourself off on a hot day

12. Be creative!

Maintain and Care for Your Rain Barrel

Rain barrels require very little maintenance. But they only work when they’re empty! So make sure to empty them between rainstorms and check to make sure the downspout is still directing water into the barrel.

If you have an overflow hose, direct that away from your foundation to your landscaping.

In freezing climates, you may need to disconnect your barrel from the downspout for the winter – just empty and turn over or store.

If your rain barrel is white and non-opaque, you’ll need to paint or wrap it to prevent algae growth. If algae grows in your barrel, a few drops of bleach will keep it clean.

If your barrel has an open hole on top, make sure to cover it with mosquito-proof netting/wire.

Link to How to Paint Your Rain Barrel:


Link to How to Install Your Rain Barrel: