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The Top 10 Most Important Things I Learned about Harvesting Rainwater

About three years ago, I started a veggie garden in my back yard in dry, dusty Norfolk, Virginia. Incredibly, the city has an ordinance that forbids sinking a well within 50 feet of any property lines. Since our house is centered on our 110′ by 110′ lot, that means the only place we could have a well is in our basement.

My other option was rain water harvesting. Fortunately, the city doesn’t have any ordinances against collecting rain water. (In some states, it is illegal to collect rain water.)

After I set up my first rain barrel, it didn’t take me long to realize that one 60-gallon rain barrel didn’t go very far during one of Tidewater’s hot, dry summers.

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One rain barrel

One solitary rain barrel

The next summer, I added more rain barrels, positioning them under a downspout that produced copious amounts of water.  The first year, my little rain barrels sat directly on the dirt, and I didn’t use them very much. They were too low, too muddy and the head pressure was abysmal.  Later that year, I built a nice wooden stand for my rain barrels.

Rain

The triplets.

The stand made it much easier to access my rain barrels, plus, the three feet of height gave them a little bit of head pressure, and improved water flow. And the 3-foot stand made it easy to fasten a hose to the spigot (a simple feat that was nearly impossible when the barrels sat on the ground).

Another 10 blogs could be written about the benefits of rain barrels, but in short - for gardening - rain water is better than chlorinated  city water. While chlorination keeps us humans from getting cholera and other nasty bugs, that chlorination will also kill off the microorganisms in the soil that helps plants thrive.

And there’s a financial incentive, too. Experts say that 40% of our summertime water use comes from the outside spigot.

In the process of using these rain barrels throughout the summer, I learned a lot of practical lessons. Below are the top 10 most important things I learned.

1)  Height is important. For every foot of height you add to your stand, you’ll gain .43 psi of head pressure. If you could manage a ten-foot stand (not advisable for safety reasons), that’d give you 4.3 psi. From a practical matter, the three-foot stand (pictured above) put the spigot at the perfect height for me. And if you’re working with a raised bed garden (like mine), you’ll need the extra height so that water can flow easily to your thirsty plants.

Raised beds

My raised bed is 24" tall, so the three-foot stand is perfect.

2)  Weight is also important. Water weighs about 8.3 pounds per gallon. Those rain barrels hold 60 gallons. That’s 498 pounds per barrel, and I’ve got three on one stand, so that’s almost 1,500 pounds of weight (when the barrels are full).  That’s a tremendous amount of weight and you should plan accordingly when building your stands. This summer, when my barrels run dry, I’ll have to pull them down and add cross-bracing to the stands. You’ll note in the picture that they’ve started to lean hard to the left. Cross bracing would have prevented that.

twisty

Let's not twist again, like we did last summer...

3)  Placement. My three rain barrels are located in my back yard, underneath a busy downspout. Water comes from the main roof (which is slate), flows down to the smaller roof and into my rain barrel.  With 10-15 minutes of a good downpour, all three rain barrels are filled up full.

rain

The downspout on this side of the house produces a lot of rainwater.

4)  Pre-screen your rainwater. These rain barrels have a four-inch floor drain in their top, with a piece of mosquito screen affixed. Too many times to count, I’ve rejoiced as a summer storm pours rain from above, only to find that the four-inch hole became hopelessly choked with the debris from the gutters, and very little of that delightful rainwater actually entered my rain barrels. My solution to this was simple. I took the aluminum-framed screen from an old storm window and stuck it on top of the rain barrel. That solved my problem. The large surface area of the aluminum screen allowed water to flow even after that first pile of gunk came washing down the spout.

Pre screen

And it's just an aluminum screen from an old storm window. The brick keeps it in place. My husband said this rig makes it look like Jed Clampett lives here, but it works.

5)  If you’re building/making your own rain barrel, put the spigot in the right place. When my neighbor saw my rain barrels, he ran out and bought some materials and made his own barrels. Every single one of his five rain barrels has a spigot at the half-way point on the barrel’s side. This means that he’ll only be able to use 50% of the water in the barrel. Not a good design. There are also entire blogs devoted to building your own rain barrel. The barrels shown here are food-grade olive barrels, used to ship olives here from overseas. Learn more here.

Rain

Spigot placement is important.

6)  Don’t get bugged. Mosquitoes are naturally drawn to stagnant water and rain barrels provide the ideal breeding ground. Screens will stop some of that, but not all. One year, I had mosquitoes crawling in through my overflow pipe.  Adding several drops of baby oil to each rain barrel will create an oily film in the water, and should stop mosquitoes from laying eggs in your rain barrel.

7)  One downside to this rainwater fun is that you’ll now have to keep your gutters cleaned out. If all that precious rainwater is cascading over the front edges of your gutters because the downspouts are blocked, your rain barrels won’t do much for you. And if your house is sheltered  by large trees (like mine), this can be a perennial problem.

Trees

Trees are pretty to look at, but hard on gutters.

8)  When the barrel runs dry, remember to turn the spigot off. Sounds simple enough, but somehow, it’s so easy to forget this little detail. Many times, I’ve gone outside to check my rain barrels after a hard rain, only to find that I left the spigot open and all that rainwater went in through the top and out through the spigot.

oopsie

It's easy to forget to close the spigot when rain barrels run dry.

9)  Maintenance. About once a year, I rinse out the rain barrels with city water. The bottom gets a layer of crud in it and the smell is horrific. I’m not sure about the microbiology of all that decaying matter, and maybe it’s just dandy for the garden, but the stench will knock your socks off.

10)  Keep water away from the foundation.  A surprising amount of water can be discharged through your overflow pipe. Make sure that water is directed away from the house.

Make sure that water flows away from house.

I keep meaning to put that downspout spillway *under* the overflow hose.

11)  Your downspout might not quite hit the sweet spot on the rain barrel.  A little extra piece of aluminum downspout is probably the simplest solution. I used a piece of Plexiglas, which also does the job nicely.

Buts

You might need to add a little extender to the downspout to reach your rain barrel.

12)  If a drought hits, and you don’t want to use chlorinated water on your lovingly maintained and chlorine-free tomato plants, you can fill one rain barrel with city water and let it sit for several days. The chlorination will dissipate in time and you’ll have chlorine-free water. This isn’t the ideal, but in a pinch, it’s one way to keep your garden chlorine free.

13)  Enjoy. I’ve had a lot of fun playing with my rain barrels. And look how my garden grows!

garden

Garden views.

garden

Tomatoes, strawberries and carrots share living space.

wow

And the world's most perfect strawberry, from my garden.

And flowers, too!

And flowers, too!

When we were kids, we’d sing this little ditty.

See, see my playmate,
Come out and play with me
And bring your dollies three
Climb up my apple tree
Holler down my rain barrel
Slide down my cellar door
And we’ll be jolly friends
Forever evermore.

If you’re in Hampton Roads, I highly recommend “Mike’s Rain Barrels.” Mike, the owner of this small business, is knowledgeable, customer-service oriented, friendly and thorough. Best of all, his prices are very affordable. You can contact Mike via email at mminor1959@verizon.net or call (757) 761-1553. The best part - he’ll deliver your rain barrels in his Toyota Priuss.

To read about Sears Homes, click here.

To buy Rose’s book, click here.

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  1. May 14th, 2011 at 14:49 | #1

    Rose: I thoroughly enjoyed reading this article. I have been debating on installing rain barrels for a couple of summers now. You may have just tipped me over the edge to take it on. Thanks!

  2. Donna Bakke
    May 15th, 2011 at 20:18 | #2

    So, I read this article yesterday morning and then in the afternoon I saw my neighbor and she said “Hey! Guess what I just bought? A rain barrel!”

  3. Stephanie
    October 17th, 2012 at 08:42 | #3

    Thank you for this helpful article. I don’t understand how the three rain barrels get filled from one downspout.

    It doesn’t seem likely that you need to move them as they fill. Too heavy. Thanks.

    Rose’s reply: Stephanie, the roof that supplies that one downspout is MASSIVE and very steep and tall. That makes for a lot of square footage. The gutters were 6″ wide, so they were pretty massive, too.

    As to moving them, we would not even try to move them unless them were empty. Fifty-five gallons of water weighs about 440 pounds, and those three tubs, full of water, weigh more than 1,200 pounds.

  4. Stephanie
    October 21st, 2012 at 19:40 | #4

    Thank you, Rose.

    I guess I didn’t phrase my question very well. Are the three rain barrels somehow connected so that water flows from one to the other, therefore only needing one downspout? How are they connected?

    Thanks again.

    Rose’s Reply: Yes, Stephanie, they are all inter-connected. When one barrel fills up, it overflows into the next. There’s a an overflow and some tubing connecting all these barrels. It works very well. :)

  5. dbb
    May 7th, 2013 at 23:32 | #5

    I would first like to say, thank you for the website. I love your work.

    However, there seems to be some misinformation going around the web about rain barrels and how to create psi.

    First thing is this, YOU CAN NOT INCREASE PSI BY RAISING YOUR RAIN BARREL 20 feet in the air.

    Sorry folks, you can’t do it.

    There are three ways to increase psi.

    1) Get a taller container (which increases the “foot column”)
    2) Get a pressurized container
    3) Get an electric pump

    Water towers which you see in most towns are usually 165-200 feet tall. They provided 50-100 psi of pressure because they are 165 feet tall, not 165 feet in the air.

    Raising your rain barrel does not increase the capacity of the rain barrel; it does not increase the PSI.

    What it does do is:

    1) Raise the faucet off the ground to create easier access
    2) Raise the elevation of the barrel so you can use your garden hose up hill

    The second item above, “raising the elevation of the barrel” will allow water to travel uphill if you have a garden at equal height to the barrel. If you have a barrel down low, the water will not flow up the hill unless under enough pressure to equal the distance traveled in elevation.

    I think the confusion comes from the link to the Virginia Community College website which has information for “Basic Hydraulics” which states:

    “Since water pressure is dependent on weight, it is also directly proportional to elevation. If the container were ten feet high instead of one foot, the pressure on the bottom would be ten times more than a one foot column or 4.3 psi. If the pressure in a water main resulted from water in a storage tank, with the top of the water 100 feet above the main, the pressure in the main would be 43 psi. (100 x 0.43 psi).

    The difference in elevation which determines pressure is referred to as head. A 100 foot head has a pressure of 43 psi.”

    What I believe is confusing people is “elevation of the container” verses the “elevation of the top of the water from the main”.

    I hope this fixes things and that other people will catch on to this misuse of wording.

  6. May 8th, 2013 at 07:17 | #6

    @dbb
    Thanks, DBB.

    I’m grateful for the clarification. I’m real good with houses; not so good with physics. :)

    Thanks for taking the time to pen such a thorough and thoughtful correction!

    Rose

  7. dbb
    May 8th, 2013 at 10:51 | #7

    @Sears Homes
    Rose,

    There are a lot of variables which play in to increase the PSI of your rain barrel. Using a smaller diameter hose will help but you decrease the volume of the water. Also, the hose bib on the side of the rain barrel does not help.

    Having the bib in the center of the bottom of the barrel would definitely be the optimal location to increase the fluid dynamics (gravity fed) system.

  8. dbb
    May 9th, 2013 at 13:04 | #8

    Rose,

    Just wanted to clarify something for the readers:

    1) the psi inside the rain barrel will stay the same at any height, but the diameter of the hose and the length of the hose will change the psi as the water exits the rain barrel.

  9. Ed Nash
    April 4th, 2016 at 18:59 | #9

    You couldn’t be more right about height and pressure. Eighteen inches is a good minimum.

    I wanted to share an experiment with a soaker hose. Soaker hoses come with a pressure reduction washer that narrows the diameter to about 3/16 inch.

    Take that out, replace it with a washer, and the pressure is enough to uniformly drip onto 4 blueberry bushes (or whatever).

    I have a 15 foot hose committed to 4 blueberry bushes in well drained soil. My barrel for the soaker is 50 gallons with a splitter on the spigot. Overnight, the barrel went from full to half full.

    I borrowed your idea for the stand for 3 very similar barrels. It’s important to note that the primary barrel should be in the middle, so that you get balanced overflow to the other two.

    And you are correct in saying that they will go from empty to full over night with a steady rain.

    Despite what people think, the Pacific NW gets dry in the summer, and our summer water bill is (was) double the winter bill, owing to gardening. It will take a decade or so to pay for the barrels, but the other benefits are worth it.

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