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| A rain barrel stores some of the roof runoff at Mother Nature's Backyard |
This
is the last in our series on ‘Harvesting Rainwater’, which covers harvesting
water from the roof (and other impermeable surfaces) and rainwater infiltration
techniques. While aimed primarily at gardeners from dry climates, the ideas in
this series may be useful to others (see postings from January through June,
2013).
Storing
rainwater is an old idea that’s regaining popularity as precipitation becomes less
predictable. The concept is simple: rainwater
is stored in a holding tank until it’s needed. In some parts of the world, rainwater collected
in large underground cisterns provides water for much of the year. A number
of U.S. counties and municipalities are advocating a less ambitious goal; the
small-scale storage of rainwater for use in home gardens.
The
idea of storing rainwater may not appeal to all, particularly those gardeners living
in urban or suburban areas. Saving rainwater requires purchasing/constructing
tanks or barrels to hold the water, connecting these to the water source and
then maintaining the barrels/tanks. All
this takes a little time, money and effort.
And unless you use large cisterns – or get rain throughout the year - you can’t store enough water to make a dent in
your water bill. Small-scale water storage
is not going to save lots of money, particularly if you live in a dry climate
with seasonal rainfall.
On
the other hand, any water saved is useful water. Stored rainwater is great for watering sensitive
plants (including container and house plants) and for crafts like natural
dyeing. Once you have a rain barrel or cistern in
place, collection and use is fairly easy.
So you may want to consider saving rainwater
in conjunction with the other water management strategies discussed in the past
few months (‘Harvesting Rainwater’ series: January to June, 2013).
A
rain barrel/tank is generally fed by a downspout from a section of roof gutter.
If you haven’t read our post on ‘Harvesting Rainwater: Gutters, Downspouts and
Rain Chains’ (February 2013) you might want to do so. Even
in dry climates, the roof collects a lot of water. A general rule of thumb is:
for every inch of rain that falls on 1000 square feet of catchment area, a
little over 450 gallons of water will be collected. This amount takes into
account loss due to friction, evaporation and spillage. If you only intend to fill a single barrel,
that can be accomplished with as little as one-tenth of an inch of rain.
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| Water from roof gutters is directed to the rain barrel. Overflow drains directly into the dry swale ('French drain') |
You
can purchase rain barrels and collection cisterns at many hardware, home
improvement and garden stores. They are also available through internet
retailers, but beware of shipping costs.
The most common sizes are 35-40
gallon and 50-60 gallon, although other sizes are available. Most are made of plastic (some of recycled
plastic) and they come in an increasing range of colors, sizes and shapes. Prices for a 50-gallon barrel range from $80
to over $200 (U.S. dollars). Some kits
include the needed hardware (or are pre-assembled); others require you to
purchase a separate hardware kit. We
suggest you read the resources at the end of this posting before considering
your options.
When
shopping for a rain barrel, some features to look for include: a spigot that
can be connected to a garden hose; a fully screened intake to keep out
mosquitoes and debris; a linking system to connect additional barrels; and a sufficiently
large overflow hose so that excess rainwater can be carried away. A rain barrel
should allow the user to customize it
for their specific needs and should work dependably.
Thrifty
homeowners may want to construct their own rain barrel from a recycled food
barrel or a sturdy plastic trash can. Many
good resources on constructing rain barrels are available on the internet. We found these to be particularly good:
- https://agrilifebookstore.org/publications_details.cfm?whichpublication=2809
- http://www.heytanksla.com/resources/make-your-own-rainwater-harvesting-barrel/
- http://www.portlandoregon.gov/bes/article/182095
- http://www.hgtv.com/gardening/conserve-water-with-a-rain-barrel/index.html
Rainwater
storage requires a few additional considerations. First, a filled rain barrel is heavy (up to
400 lbs); it needs a firm, level foundation and should be tied to a wall or
post to prevent tipping. See the
resources below for more on this topic. Second, untreated stored garden rainwater should
not used for drinking. Many
municipalities require rain barrels to be labeled: ‘Do Not Drink – Untreated Rainwater’.
Be
sure to check local regulations before purchasing or installing a rain barrel or
cistern. Many municipalities allow
homeowners to store rainwater in small rain barrels without a permit; larger
cisterns require a building permit in most areas. Los Angeles County has a 4-tier
system that covers everything from small-scale rain barrels (Tier 1) to larger
storage facilities. To learn about Los
Angeles County regulations see:
- http://spoutingoff.wordpress.com/2011/11/08/saving-for-a-rainy-day/
- http://www.publichealth.lacounty.gov/eh/docs/ep_cross_con_RainwaterMatrix.pdf
Water
conservation must become a way of life as our climate changes. Along with rainwater infiltration, rainwater
storage can play a role in maximizing our scarce water resources. Excellent internet and print resources are available,
covering all aspects of rainwater storage - many specifically written for the
homeowner. We suggest you read more
before deciding whether rainwater collection is for you.
Good
resources for homeowners
- Rainwater
Harvesting for Dry Lands. Brad Lancaster, published by Rainsource
Press. 2006. 8.5x11, 183 pages, over 150 illustrations. ISBN
0-9772464-0-X. $24.95
- http://aggie-horticulture.tamu.edu/earthkind/files/2010/10/rainwater.pdf
- http://sarasota.ifas.ufl.edu/fyn/rain_barrels_guide.pdf
- http://www.rainbarrelguide.com/
More
detailed resources on saving rainwater
- http://www.twdb.state.tx.us/publications/reports/RainwaterHarvestingManual_3rdedition.pdf
- http://ag.arizona.edu/pubs/water/az1052/
We
welcome your comments (below). You can also e-mail your questions to: mothernaturesbackyard10@gmail.com
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