Kathleen Groll Connolly

Rain Barrels Provide More Than a Drop In The Bucket

By Kathleen Groll Connolly

“Into each life a little rain must fall,” the sad sentiment goes. More often than not, I wish the saying would come true on my sandy coastal Connecticut garden. If I had to rank, from most favorite to least, all the tasks that maintain my 4500 square foot vegetable and flower garden, Rainbarrel watering from a hose would come in dead last. It’s the one task that makes me question my passion for the green stuff. Lugging hoses around our two-acre yard, trying to skip over tender stalks, walking back and forth to remove kinks – all of this is about as much fun as watching laundry tumble dry down at the Laundromat.

As my gardens got bigger and more numerous over the past ten years, rain barrels started to catch my eye. I took my first foray with a converted garbage can. Then came an old compost barrel. Eventually, my husband bought me two rain barrels for Christmas. Then we added rain diverters to some downspouts. Finally, my rain barrel operation was in business and it’s been very helpful.

If the number of gardening catalogs offering them is an indication, one can only think that more and more gardeners are looking for the same solution I was. Rainwater collection is an old-fashioned idea that fits today’s environmental needs. Rain barrels fly under the radar screen of municipal watering regulations. If your house is on a well, rain barrels can help preserve your home supply during dry times. And if you aim for a chemical-free landscape, rainwater is a winner. Rainwater collected from most roofs is very clean. Wood, metal or asphalt shingles add little to the water that is of concern to the home gardener, even vegetable gardeners. (However, old tar or asbestos shingles, or lead pipes are a concern.)

Though they seem like simple devices, there are a few things you need to know. Otherwise, you may be like me and wind up reinventing your water collection operations a few times before you feel as though you “got it right.”

How to Select a Rain Barrel


There are four primary features you’ll want to consider: size, material, the lid and intake openings, and water distribution.

How big a barrel?

Say you have a 10 x 10 garden, or 100 square feet. During the growing season, assume it will require the oft-quoted inch of rain per week. One inch of rain on 100 square feet of garden is about 62 gallons. (See the sidebar titled “How Much Water?” on this page.) A 60-gallon rain barrel would just about meet the need of that 10 x 10 garden for one week. So, let’s say it rained one week but not the next. Your stored water would give you what you need to get by in the dry week.

In another scenario, say it rains only a sparse 1/4-inch in a week. If you have a 1000-square-foot roof (25’ x 25’) draining into your rain barrel, that 1/4-inch will provide more than a 60-gallon refill. That’s because one-quarter inch of rain on 1000 square feet of roof will provide about 100 - 125 gallons. This is a good reason to hook up a second rain barrel to catch the overflow, a feature that most rain barrels offer. Now you can supplement nature’s scarcity with a generous 120 gallons – enough to spell you for two weeks.

Use the rough calculations above and in the sidebar to estimate your watering needs. My own recommendation, based on experience with four rain barrels, is to get the biggest you can afford and can fit into the available space. The price per gallon generally decreases as the barrel gets bigger.


According to Joan Freele, general manager of New England Rain Barrel Company, rain barrels are very common in Great Britain. That’s where she first saw them in use. “Everyone has a rain barrel there,” she says. “They’re available at every hardware store down the street, so to speak.” But when she and her husband returned to Massachusetts in 2000, she couldn’t find one. That led to the creation of the company she now runs in Beverly, MA. New England Rain Barrel Company sells its 55-gallon barrels through municipalities and environmental groups. She shares some insights on what to look for in rain barrel materials. Three primary features should concern you.

Is it made of food-grade plastic? Many rain barrels are made from recycled food barrels that contained juice, pickles, olives, and other comestibles. While the barrels cannot be reused for food, they are safe for rainwater collection, according to Joan Freele. “All of our barrels are made from recycled food grade plastics,” she says. Freele cautions against black plastic containers, which are often manufactured for chemical containers.

If you’ve been following the news about plastics and microwaves, you may have read that all plastics leach some amount of chemicals into the materials they contact. This is particularly true of PVC (polyvinyl chloride) and polystyrene plastics when they are heated. PVC plastics carry the recycling number 3; polystyrene is number 6. These are best avoided in your rain barrel selection.

Is it UV stabilized? Plastic ages in sunlight and heat, becoming discolored and more brittle with time. UV stabilizers lengthen both the appearance and life of your rain barrels.

Is it the right color? Almost any color will do – if it’s not black or white. During the height of summer, when you need water the most, black plastic can retain too much heat. Hot water on a hot summer day can cook your plants. For this reason, homemade barrels of black plastic garbage cans are not recommended. White plastic food buckets are common and readily available but they’re not opaque. Says Joan Freele, “Within a week, you can get quite a lot of algae in a white bucket.”

Lid and Intake Openings

The lid is arguably the most important aspect of your purchase, for several good reasons.

Safety: Rain barrels may seem as innocent as a daisy by the roadside, but they do have some hidden dangers. They MUST be covered at all times. This is because children, pets, and backyard wildlife may be attracted to them, fall in and not be able to get out. (Last year, for instance, a local squirrel went for his last swim in one of my rain barrels when I left it uncovered for just a few hours.)

Some rain barrels are sealed. They have solid tops with only a screened, louvered 6” opening for water intake. Others have a solid screw-on lid with a six-inch opening. Yet others have lids made entirely of screen. I don’t recommend these, as screen is too weak to withstand the weight of a pet or a curious child’s hands. It also admits a lot of algae-producing light.

There is one safety disadvantage to sealed models: the weight of the filled barrel. Since a rain barrel must be elevated to take advantage of gravity, a person or pet could be knocked over and injured by the weight of a full rain barrel. It must be placed on a secure broad base to prevent tip-over accidents. A barrel with a screw-on lid would spill its water quickly in a tumble. Someone standing nearby might get wet, but they’d be unlikely to get hurt.

Mosquito-prevention: No one wants their rain barrels to become mosquito nurseries. According to Theodore Andreadis, Chief Scientist at the Connecticut Agricultural Experiment Station in New Haven, this is a concern because the Culex mosquito that carries West Nile Virus will breed in a barrel. “Your first line of defense is the lid,” says Andreadis. “Your second line of defense is to drain the barrels faithfully once a week. Once the larvae are on the ground, they become desiccated and die.” Andreadis adds that if you don’t want to drain it weekly, mosquito dunks containing Bt can be added to the water. “They are effective and we have no environmental concerns with them,” he says.

The sealed, solid lid with a screened, louvered opening is arguably the most effective mosquito screen, followed by screw-on tops with small, screened openings.

Cleanliness of rainwater: A good lid can keep small particles and bird droppings out.

Careful choice of the lid can make a lot of difference in your ultimate satisfaction.

Water Distribution

There are two features to understand in water distribution: barrel height and overflow.

Overflow, Hoses, and Barrel Height

Most barrels come equipped with an outlet near the bottom and a short hose. Manufacturers offer both brass and plastic fittings. (Brass is potentially longer lived.) You can certainly add hose length, but the farther your garden is from your barrel, the higher you’ll want to station it. This is especially true if you’re going to use it with a soaker hose or a sprinkler. In my experience, barrels must be at least 12” above ground.

Overflow: A good rain quickly fills a barrel, so you should only consider models that are equipped with overflow valves and hoses. These allow you to divert the overflow away from your house, or link another barrel to the first. Otherwise, water can pool up around the base of your foundation – an obvious drawback.

Helpful as they are, rain barrels are only one element in your water management plan during long dry spells. Look at what happens during a 12-week drought. Your 10 x 10 bed theoretically needs 744 gallons over 12 weeks – the contents of ten 80-gallon rain barrels. Under these extreme conditions, rain barrels are not likely to be the sole solution – since most of us don’t want ten aboveground storage devices in our yards. You probably want other strategies, such as drought-tolerant plantings, 2” – 4” of mulch, and watering only in the early morning, to get you through the extremes.

Rain barrels can be an excellent addition to your water management strategy. Just keep in mind some of the topics discussed here and you’re on your way to adding a great asset to your collection of gardening tools and techniques.

First appeared in July/August 2004, Connecticut Gardener

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How Much Water?


One inch of rain on a 1000 square foot roof equals 625 gallons. (This is derived from the fact that one cubic foot of rain equals about 7.5 gallons.) Assuming that you’ll loose about 10% of the water to gutter overflow, roof absorption or other inefficiencies in your collection system, you’re likely to capture 562 gallons during a one-inch rain.

How much water can you capture?

Your collection area in square feet: _______/1000 = ________%

Multiply the percent by 625 gallons:

_______% X 625 = ______ potential gallons

Multiply potential gallons by the expected capture, such as 90%

______ Gallons x .9 = ________ Projected capture

How much water will you use?

You need to consider if the garden is on a slope, if it has sandy soil, if it is rocky or other factors that might increase the water need. The intensity and duration of rainfall is also a factor. Assuming a perfectly flat site, a slow, steady rain and soil that can retain some water, use the following calculation:

Your garden’s square feet/100 square feet = ______%

Multiply the percent by 62.5 gallons.

_____% X 62.5 = gallons required

Multiply the required gallons by the expected capture, such as 90%

____ Gallons required x .9 = __________ Projected need


rainbarrel downspount diverter

Rainbarrel Downspout Diverter