If you're in an area that is facing a drought this summer, like I am, you might be thinking of ways to combat it in the garden. Enter the rain barrel!
Home gardeners often use rain barrels to collect rainwater from roofs as a supplement to summer irrigation. Rainwater is a natural and unchlorinated water source for plants, but rooftop runoff can be contaminated by chemical and biological pollutants.
Today we talk about the practicality of rain barrels, possible contaminants and where they come from, and how to safely use rain barrel water in the garden. Let's dig in!
Resources and Citations:
Chang, M., M.W. McBroom, and R.S. Beasley. 2004. Roofing as a Source of Nonpoint Water Pollution. Journal of Environmental Management 73: 307–315.
Chen, J.J., R.C. Beeson, Jr., T.H. Yeager, R.H. Stamps, and L.A. Felter. 2003. Evaluation of Captured Rainwater and Irrigation Runoff for Greenhouse Foliage and Bedding Plant Production. HortScience 38(2): 228–233
de Kwaadsteniet, M., P.H. Dobrowsky, A. van Deventer, W. Khan, and T.E. Cloete. 2013. Domestic Rainwater Harvesting: Microbial and Chemical Water Quality and Point-Of-Use Treatment Systems. Water, Air, and Soil Pollution 224(7).
Lim, K.Y., and S.C. Jiang. 2013. Reevaluation of Health Risk Benchmark for Sustainable Water Practice through Risk Analysis of Rooftop-Harvested Rainwater. Water Research 47(20): 7273–7286.
Shuster, W.D., D. Lye, A. de la Cruz, L.K. Rhea, K. O’Connell, and A. Kelty. 2013. Assessment of Residential Rain Barrel Quality and Use in Cincinnati, Ohio. Journal of the American Water Resources Association 49(4): 753–765.
POTENTIAL CONTAMINANTS IN RESIDENTIAL RAIN BARREL WATER (HOME GARDEN SERIES), Washington State University Extension
100-Year-Old Way to Filter Rainwater in a Barrel - The Prepper Journal
Just Grow Something Gardening Friends Facebook Group
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This is positively farming media.
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So here in Missouri, the majority of the state is either
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in abnormally dry conditions all the way up through extreme
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drought. In our county here in West
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Central Missouri, we are in a severe drought classification
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according to the US Drought Monitor, which means that soil
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cracks are large and deep. Surface water levels are very
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low, trees are stressed and vegetable produce is smaller and
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yields are decreased. And we are absolutely seeing all
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of these signs in our area just South of us and to the east of
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us. They are in that extreme drought
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category which includes things like building foundation damage,
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occurring burn bans, hay and water for cattle is very
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limited. Producers are hauling water in
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mature tree, death is common, ponds are drying up and then
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mandatory water restrictions are implemented.
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And I know that we aren't the only ones that are facing this.
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We faced it last year and that was more widespread than it is
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this year, but it certainly is occurring all over and more
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frequently. So in times when we get to
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severe or extreme drought and we may start to see those water
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restrictions, it's not uncommon for home gardeners to turn to
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using rain barrels to collect rainwater from their roofs as a
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supplement to their summer irrigation.
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It makes sense. Rainwater is natural, it's
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unchlorinated, and it's a great source for our plants and even
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for our animals. But rooftop runoff can be
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contaminated by chemical and biological pollutants, either
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from atmospheric deposits or from the roofing material
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itself, or, you know, from birds and other critters that happen
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to come across our roof. On today's episode of the Just
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Gross Something podcast, we're going to look at residential
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rain barrel water safety. Why it can be important to use
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rain barrels, especially if we're trying to reduce storm
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runoff in more suburban areas. The practicality of collecting
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rainwater, what contaminants we might find in our rain barrels,
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where they come from, and how to prevent them from contaminating
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anything in our gardens. Let's dig in.
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Hey, I'm Karen and I started gardening 18 years ago in a
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small corner of my suburban backyard when we moved to A5
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acre homestead. I expanded that garden to half
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an acre and I found such joy and purpose in feeding my family and
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friends. This newfound love for digging.
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In the dirt and providing for others prompted my husband and I
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to grow our small homestead into a 40 acre market farm.
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When I went back to school to get my degree in horticulture, I
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discovered there is so much. Power in food.
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And I want to share everything I've learned with as many.
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People as possible. On this podcast, we explore.
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Crop information, Soil health. Pests and diseases plant.
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Nutrition, our own nutrition, and so much more in the world of
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food and gardening. So grab your garden journal and
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a cup of coffee and get ready. To just grow something.
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So we have kind of a unique situation with our farmhouse.
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There is actually a giant concrete cistern that is
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underneath our back deck. And it came with the house.
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It was it was built with the house, and it holds a ton of
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water. And the first couple of years
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that we were here, we actually did use that water mostly for
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our livestock. Somewhere along the way the the
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feed inlets have gotten blocked and the the pipes that lead to
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it have become detached. We needed to be able to drain it
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and clean it and we haven't done that yet.
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But trust me when I say we are seriously considering just
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revamping that whole system and being able to use that cistern.
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I think it holds about 1500 gallons of water, but that would
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all be run off from our roof. We have in the past also done
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just your standard rain barrel and this is more like what
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you're going to see in most residential areas is just a
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garden rain barrel. In general, those are favorable
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things. They're they're better for
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specifically reducing stormwater runoff in neighborhoods than
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maybe rain gardens or bioswales or other types of trenches,
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which can be more expensive and can kind of be, you know, looked
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upon unfavorably by, say, your homeowners association.
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But, you know, rain barrels, hey, you're collecting the
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water, You're reducing your water bill.
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And so it can be a good, you know, motivation for people to
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be able to put these in, especially when we're facing
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droughts and possibly water restrictions and you are growing
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a garden. Now it is interesting to note
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that rainwater collected from rooftops has been tested on
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plants, in containers and those that are in gardens and
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landscapes and. Good results have been seen with
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these with no apparent plant disease or disorder problems in
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several of the studies that I saw.
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But rain barrel water is untreated and so there are
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legitimate safety concerns about exposing us and our pets and our
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garden produce to possible contaminants.
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So there are many studies that have shown that rain barrels are
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reservoirs for toxic materials and pathogenic microbes.
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So these kind of fall into two different categories.
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You've got biological and you have chemical.
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The biological contaminants would be things like bacteria,
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cyanobacteria, fungi, protozoa. That bacteria also includes
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fecal bacteria. And then chemical contaminants
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would be things like metals, heavy metals, specifically
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different particulates and pesticide residues.
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So researchers have looked at the different loads of the
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nutrients that might be in there, this heavy metal content,
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the pesticide residue. And in North America, the main
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concerns are fecal contaminants and heavy metals.
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When you look at other countries, it's different.
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Overseas, say Germany, France, we're looking at heavy metals,
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nutrients, pathogens. In the Netherlands, it's heavy
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metals and mosquitoes. Australia, you're looking at
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heavy metals, mosquitoes and pathogens.
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So they've kind of broken it down in international rainwater
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collection studies going back as far as 1996 to see what we are
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at most risk from now. The contaminants, especially the
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chemicals, are actually carried through the atmosphere and then
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they're deposited by wind or rain onto our roof surfaces.
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So particulates, heavy metals, sprayed materials like
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pesticides. Land on our roof.
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And then, of course, they're washed into those collector
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barrels the next time it rains. And those pesticides can remain
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potent for weeks or even months after entering into the rain
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barrels. And then, of course, we have
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those biological contaminants. These can come from the tree
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canopies, or they're deposited directly by birds or squirrels
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or raccoons or whatever other animals decide to crawl across
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our roofs. And our biggest concern here of
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course is feces, because they are a source of pathogenic
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bacteria and viruses and all kinds of stuff that can very
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easily survive in a rain barrel. In fact, they did a long term
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study back in 2013 or that ended in 2013.
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That found unexpectedly high levels of coliform bacteria.
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Those are the things that are used as indicators of human
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pathogenic bacterias. That water was consistently
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above what the US EPA standards are for coliform bacteria, which
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says something considering sometimes what the EPA standards
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are now, even though those levels were alarmingly high in
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those studies. It does not appear that there
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were any reports of illnesses related to the rain barrel
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water, and the authors of the studies also saw that those rain
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barrels contained really good microbes and a very rich
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microbial community, that that actually probably contained
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predators that fed on that harmful bacteria, which likely
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controlled the levels of that bad stuff.
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So All in all. We shouldn't be afraid of
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collecting our rainwater, but there are some things that are
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going to affect that rainwater quality and ways that we can
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kind of increase it. So the roofs themselves are also
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going to affect that, that quality of that rainwater,
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right? We've got metal flashing,
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there's gutters, there's galvanized nails.
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So those things are all going to be sources of heavy metals.
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They contain things like zinc and lead and chromium.
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And then if you have a composite roof, those shingles are going
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to contribute contaminants. There's roofing membranes and
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tar paper. And then again, they're going to
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collect those pesticides that come in just on the air.
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So the greater the slope of your roof.
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The more likely it is that these contaminants are going to end up
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in your rain collection because you know it's less likely that
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they're going to remain on the the surface simply because it
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takes less rainfall to make it run off of a sloping roof.
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So those contaminants are going to wash off the the roof more
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frequently. The more rough the surface of
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the roof is, the more likely it is that it's going to catch and
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retain those wind deposited particulates and and the fecal
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matter. Metal roofs have lower
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concentrations of biological contaminants, but obviously
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they're going to have higher levels of some of those heavy
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metals. Asphalt shingles contain lead,
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not really something we want green roofs, which we usually
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say are really good as far as filtering water.
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And environmentally they have been found to have things like
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arsenic and other heavy metals from the growing mediums that
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are being used. So these are all things that we
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just need to be taking into consideration when we are
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looking to install rain barrels. I still think that they are an
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absolutely valuable source of additional water for our gardens
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and even for our landscapes. And there are simple research
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based practices that we can use to take advantage of the rain
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water that we can collect from our roofs that are going to
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reduce the risks of contamination.
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On us and our gardens, which includes of course protecting
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our produce. We'll talk about that right
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after this. So some of the action items for
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gardeners, we're using roof collected rain barrel water.
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The first thing is to know your local pollution issues if there
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is a history of airborne pollutants from.
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Local industry or agriculture in your area?
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Then you likely want to have your rain barrel water tested
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for a lot of these contaminants just to be on the safe side.
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You also want to avoid collecting rainwater when the
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air quality is really low, and I know that has been an issue in a
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lot of different places here recently.
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Whether it's smoggy or there are really low wind speeds, or you
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know, there's the temperatures have have gotten kind of crazy.
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I mean, you generally know when the air quality is low.
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That also adds to the contaminants that might possibly
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run off of your roof. If you've used a Moss removal
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product on the roof, you don't want to be collecting the water
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immediately following that. And then of course, if you know
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that pesticides have been recently applied nearby, it
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doesn't take a lot. You don't want to be collecting
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the water at that point. You also want to make sure that
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you are using good hygiene when it comes to the barrels.
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Specifically, we want to keep them really tightly sealed so
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that we don't end up with mosquitoes.
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So it whether it is some sort of a cover completely on top or
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it's a a filter combined with a cover, whatever it is, we want
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to prevent the mosquitoes from being able to get in there and
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breed. And there are larvacides too
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that you can put in rain barrels.
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They're pesticides. They have to be labeled for rain
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barrel use. But they will take care of the
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mosquito larvae if you do end up with some in there.
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But to me, honestly, I mean, I don't want the pesticides
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running off my roof into my rainwater, so why would I want
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to intentionally add it? So of course we're not drinking
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this water and we shouldn't be giving it to our pets to drink
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either. This is just for our gardening
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and our landscapes. So don't drink it.
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Don't touch your eyes or your mouth.
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After you've handled it, wash your hands.
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After you've used the rain barrel water and then just make
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sure that you are cleaning the rain barrels regularly to make
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sure that you are removing any sort of residual contamination.
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We have had IBC totes which I don't know if you've seen them,
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they are sort of opaque, so they're not solid all the way
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around and we've used those in the past for rainwater
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collection. And those need to be cleaned
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much more frequently because they actually would develop
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algae in the inside because the the sun could get through.
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So I know, we know having to clean it is kind of a pain in
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the in the butt, but it's definitely, it's definitely
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worth it and it's definitely necessary.
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You also want to make sure that you are washing your produce
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that's coming out of your garden before eating it.
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If you are using rain water to water your garden, this is
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specifically important for leafy greens.
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There's a reason why every time we hear a major recall on
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produce, a lot of the time it is a leafy green of some sort.
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They are very susceptible to contamination, especially with
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anything that is a waterborne pathogen.
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Fruits too are also kind of susceptible to this, so tomatoes
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and cucumbers. So you definitely just want to
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be making sure that you are cleaning your produce before you
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are eating it. And then the other thing here
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too to do is to install a diverter.
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So that way you can direct that first flush of rainwater runoff
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into like your lawn. Or you can build a little rain
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garden or something just away from the collector barrels
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because that first flush of harvested rain is going to have
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the highest levels of contaminants.
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This is also. You know going to be the case if
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you are have been in a drought situation and you haven't had
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rain on that roof for a very long time, a lot more material
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is going to be deposited on the roof and into the gutters during
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that dry period. So as tempting as it would be to
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immediately start collecting whatever rain would start coming
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down in, when you're in the middle of a drought, it really
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is important to flush away. That that first rainfall because
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it is going to move those deposited materials off the roof
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and into your gutters and then into your rain barrel.
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When you're setting up a rain barrel you want to make sure
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that you are have some sort of a screen or other filter in place
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that is going to prevent the roof debris from entering the
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rain barrel. So a leaf screen or other some
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some other type of a gutter cover up on your roof to start
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with. Is going to be a good way to do
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this. And then also having an
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additional one in the feedspout that that feeds into your
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barrels. So the more screens, leaf
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screens and things that you can put in place is going to help to
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keep that stuff from ever entering the barrel in the 1st
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place and then using activated charcoal filters before you feed
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the water into the garden. So these are going to remove the
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sediments, they're going to remove the organic contaminants.
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Some of the mineral contaminants, they're not going
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to do anything for the heavy metals, but they will do just
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about everything else. And you can use just a regular
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activated charcoal filter. I actually found a fantastic
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reference that came from an old book out of I think it was the
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early 1900s and it's called Household Discoveries.
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And it was written, let me look here, Household Discovery's
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revised edition and Encyclopedia of Practical Recipes and
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Processes, and this is copyright 1908.
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And so in this book they talk about a way to create a charcoal
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filter for your rainwater. And this stands up, I think,
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over the last 100 or so years as a way that you would be able to
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safely use your rainwater. And it actually.
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This cleans it to the point where it could possibly be
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drinking water. So it talks about taking a
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barrel or an oak tub that's never been used and creating a
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false bottom about 3 or 4 inches from the bottom of it and then
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putting perforated holes in it and covering it up with a clean
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piece of white canvas. And then layering on some clean
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pebbles about 3 to 4 inches deep and then layer of sand and
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gravel and then coarsely granulated charcoal.
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Tamping that down and repeating that until you get about a foot
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from the top and then adding a three inch layer of pebbles and
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covering it with canvas as a strainer.
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Now they just created a charcoal filter and something that we pay
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a lot of money for. You could do this on a smaller
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scale with say a 5 gallon bucket.
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So that you're able to collect the maximum amount of rainwater
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in your barrel, but then still filter it safely through that
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little charcoal filter. There are lots of ways to do
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this. I just thought it was very
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interesting that 100 years ago, of course they already had this
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technology because, well, they didn't have our technology.
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I think it bears repeating that, you know, this rainwater
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collected from rooftops has been tested, OK?
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It's been tested on plants. In containers, in the ground, in
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landscapes, in our gardens, and in all cases, there were good
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results. There were no apparent plant
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diseases or disorder problems. And even though these safety
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concerns are legitimate and we want to err on the side of
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caution, there weren't any reports of anybody getting sick
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from this either. So I absolutely am a proponent
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of using rainwater collection. I think especially as we get
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into a situation where there's less and less fresh and clean
00:19:10
water available to use, it's going to be even more important
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for us to use these sort of non potable water sources.
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To do things in our lawns and our gardens and our landscapes
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because it's an increasingly difficult resource for us to be
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able to get, especially now that we again are having more and
00:19:31
more problems with drought. And also, you know, areas that
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are chronically dry or seasonally are very arid, I
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think it's important. So hopefully this gives you a
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little bit of encouragement if you are in an area where you're
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starting to see some drought. Or where maybe you had one last
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year and it's not a good feeling to be in.
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Consider some rain barrels. Just consider doing it safely.
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Until next time, my gardening friends, Keep on cultivating
00:19:57
that dream garden and we'll talk again soon.
00:19:59
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