Magical rain barrel psychology

In earlier posts I first exposed the cult of the rain barrel as a marginally efficient sop to green guilt but then had an Ah Ha moment in the second post when I related the prevailing theory of how unengaged people will become engaged people through the magic of rain barrels.

The magical rain barrel theory says that Flo and Joe Sixpack will suddenly throw off years of disengagement and disregard for the environment after receiving a free rain barrel from the City of LA(1) After work Joe will park his 4WD full sized truck in the lot-length driveway of their 50's era SFR, amble over to the rain barrel, and switch on the irrigation for his organic free-range tomatoes. He'll share the tomatoes down at the local VFW Hall and, over cold Budweiser, tell the story of the enabling technology of the rain barrel. In doing so he will spread the true gospel. It'll be viral!


This theory only works on people that are already on the cusp of wanting to do something green. Among LA's west side population I'll take a guess that fraction is at most 5% of households. So if you want to make inroads in 5% of households, go ahead and give out free rain barrels. Heck, I'll take one, though even on my somewhat capacious lot I don't know where I would conveniently keep it. On second thought, cancel my rain barrel. Just send me a crew of workers for a weekend to redo the drainage in my yard to more effectively infiltrate water on site.

What sorts of efficiencies push people's buttons and get them excited and engaged? Hardnosed reporter Susan Carpenter, the Realist/Idealist of LA Times was so thrilled with her $500 investment in 3 rain barrels that she put it at number three on her top list of green innovations. She lived with them for the past two to three years and based on my guess that her roof was larger than 600 square feet, she was probably getting rainwater collection efficiencies no better than I cite in my first blog post - 20% to 47% (her roof is larger but her total barrel size is larger too so these numbers are educated guesses for sake of discussion). But because no one is as efficient as the hypothetical water stud in that post, let's assume Susan had an actual 10% to 24% efficiency out of her rain barrels. She says that it lasted her a month into summer.

And she got excited! So here's a person with green tendencies, presumably somewhat skeptical (she is a Realist, after all) getting excited over an outlay of $500 that netted one less month of watering their fruit trees in summer.

I guess magic does happen.

1. "The City of Los Angeles, Department of Public Works, Bureau of Sanitation, Watershed Protection Division (Stormwater Program) rolled out the City’s first free Rainwater Harvesting pilot program in July 2009.
Residents that sign up for the program will be eligible for complimentary installations of (1) rain barrels (2) downspout disconnections, or (3) custom-made planter boxes for businesses. The captured rainwater will then be either routed to pervious surfaces or used for on-site irrigation."


  1. In the UK we have a British Standard for rainwater harvesting, the BS 8515 2009 which limits the size of rainwater harvesting tanks to avoid the risks involved with storing stagnant water, e.g. Legionnaires Disease.
    We are limited to a tank which is the sammler of either 5% of the annual useage or 5% of the gallonage of water that falls on the roof/year.

  2. Your link has interesting reading. It's inspiring to see that in areas with regular and high annual rainfall (the UK's areas with the least rainfall are on average 24" annually) that there is an approved method to use rainwater inside the house. This probably isn't something that's in the near future for rainwater in southern California given our Mediterranean rainfall pattern.

  3. I looked over several years of water, electricity and gas bills, getting ready for the shred event at work.

    Our monthly bills for water, elec and gas are around $30-50, $20, $30-50. I knew that photovoltaic solar electric panels were a waste of money for my home, but I had been thinking of adding solar-thermal hot water heaters on the roof.

    Assuming it heats 50-70% of the hot water we use, and that about $20/mo of our gas bill goes to heating water, it will take a long time to recoup the $2000 cost.

    How long would it take to recoup the cost of relandscaping to capture more rainwater in the soil?

    It will probably only pay off with tax breaks/rebates and if the cost of water and energy go up from their current levels.

  4. I think that the payoff to recoup your costs for modest garden modifications might work out within a reasonable time.

    More to the point, the efficiency per dollar spent could be much higher than the ~10% efficiency that your average person would see with a rain barrel.

  5. In reply to Brent, it is very likely that by 2015, rainwater harvesting will become mandatory for all new buildings in the UK regardless of annual rainfall.
    Already, rainwater harvesters gain points for the building under the 'Code for Sustainable Homes'.