Maceo Carrillo Martinet, Ph.D.


KUNM, the University of New Mexico community-powered radio station, recently had an entire call-in show on conserving our state’s water resources. One person made the comment that NM should enact laws and policies that make it easier for someone to harvest rainwater for indoor, non-drinking use, such as flushing the toilet or washing your clothes. One of the guests on the show, a well-respected university teacher and water resources expert, responded by saying, “You know it sounds like a real attractive solution, but it turns out to be very expensive.” To prove his point, he explained that he recently bought a rainwater harvesting tank for home use that cost him $500, and that “every time those tanks fill up, which is about three times last summer, I save 60 cents.” No further explanation was provided. I knew rainwater harvesting can be expensive, but I was not convinced that it was not really a feasible conservation tool. I decided to do some of my own calculations.

Personal Water Economics

If I use every drop of water collected in my 550 gallon rainwater harvesting tank at home (which I do), I save a measly $3–$6 a year on my water bill, which totals about $305. This is the same dreary scenario shared during the talk show. It would seem that the water expert is correct in declaring that rainwater harvesting is just too expensive, but this is just part of the story.

The $3–$6 savings I get from using harvested rainwater is estimated by using Albuquerque’s water utility price per gallon of water/wastewater, known as the commodity charge. Commodity charges are defined as those costs associated with pumping, treating and delivering each gallon of water and wastewater to each customer ( Averaged from 2008–2011, the rate I pay at a multi-residential unit for each gallon consumed is roughly 3/10th of a penny (which includes wastewater and paying back the drinking water project). That’s right, 3/10th of a penny per gallon, or about $2.64 for 1,000 gallons! Using this measly commodity charge rate, it would take me between 70–140 years, depending on how much it rained, to recoup the cost of my water tank with the savings on my water bill.

But let’s take a closer at how my water bill works. I pay about $46 every year on the water consumed and wastewater produced. In total, however, I pay about $305. The other $259 of charges are lumped together in what are called fixed costs, which include base charges, taxes and franchise fees. Fixed costs are defined as those charges required to recover the cost of services “associated with providing capital facilities (pump stations, reservoirs, transmission lines, wells, etc.).” Fixed costs are charged to the consumer regardless of whether there was any water actually consumed. These costs are likely to increase in the near future to upgrade aging pipes and wastewater treatment plant infrastructure.

However, when we look at the bigger picture, which includes all the energy- and infrastructure-related costs associated with delivering water to a home, it becomes clear that the commodity charge obscures the true price of water, and, as seen at the beginning of our story, can easily misguide an assessment of the true merits of rainwater harvesting.

Water is only “cheap” because of the way we have set up the water bill payment system, with the commodity and fixed costs as separate entities and the commodity charge being the defining “value” of a gallon of water. According to the commodity charge, water is extremely cheap. When we factor in the costs associated with the infrastructure and labor needed to deliver that water from the river (or groundwater) to your home (and wastewater from your home back to the river, treated), water is truly not “worth” 3/10th of a penny per gallon when it flows from our tap. If we measured the “value” of my home rainwater harvesting system, using both commodity and fixed costs, or all the costs associated with getting that water to my house, then my small rainwater harvesting system off my garage would actually save me between $20–$41 on my water bill per year (instead of $3–$6), and the return on investment would take 10–20 years, a much more reasonable return. Interestingly, the rebate I received from the water utility did include both the commodity and fixed costs on my water bill.

The True Value of Water

Although rainwater harvesting is clearly an essential tool for water conservation, the way we “value” water actually diminishes the economic viability of rainwater harvesting and possibly other critical conservation measures. While the payment system might make sense from the water utility’s operations and maintenance standpoint, since it secures the recovery of their costs regardless of water conservation, it works to our detriment when it is used to evaluate water conservation activities. The real reason why rainwater harvesting “turns out to be very expensive” is due to the magic of artificially separating the water system into pieces, rather than looking at it as a whole—let alone taking into account the reality of living in a desert.

There is something inherently backwards in discouraging rainwater collection in the desert because it is too expensive. In an environment that only receives about eight to nine inches of rain all year (four inches in 2011), and a bleak-looking forecast, it seems to me “too expensive” not to collect rainfall and use it to supplement our daily needs, as well adopting other outside-the-box conservation measures. This would seem to be a no-brainer, especially considering Albuquerque recently paid $500 million to build the San Juan – Chama Drinking Water Treatment Plant so that we can drink Rio Grande water, helping offset our unsustainable use of groundwater. Furthermore, the insanely low commodity charge for water is in stark contrast with the astronomical price we pay for highly coveted water rights in the Southwest.

As this example shows us, the dollar value of something is a very deceiving way of defining that something’s value. This is an important point, one that is brilliantly explored in Raj Patel’s recent book, The Value of Nothing. According to Patel, “We’ve been socialized into thinking only in terms of the money value of something, but thinking this way shrinks us.” Going back to the water resources expert, rainwater harvesting was tossed to the dump simply based on monetary terms defined by a market value system. Thinking just in those terms, you would be blinded from the huge potential that rainwater harvesting does embody, even if we only get a few drops here on the desert. For example, last year, with just one full 550 gallon tank and a frugal lifestyle, I was able to flush my toilet twice a day for about eight months and still had enough water to support a small but productive garden (growing crops native to the desert) for about two months into the growing season. I did all this with a tank the sky filled up for me for free, with me using gravity to move this water around! I estimate that if I were to get smarter in harvesting the rainwater that runs off the rest of my house, I could meet all my indoor non-drinking water needs (e.g., flushing toilets) and at least half my outdoor water needs for an entire year!

A New Value System

In my calculation of the cost and benefits of rainwater harvesting, I did not include the value of using rainwater to grow native vegetables and fruits, increase food and water sources for insects or birds, and bring more organic matter to the soil; not to mention the ultimate satisfaction of not using drinking water to flush my toilet. Though these benefits are valuable to me and the community, it is almost impossible to put a dollar amount on them, and therefore they are removed from any cost-benefit analysis based solely on money. This is a very important point that cannot be tossed to the wayside as a nice gesture, but it is impractical, especially for an educator. This system of “value” is something that we alone created, and that we alone can change.

How we relate to rainwater or anything that is essential to life and a finite resource, should not be solely determined by the price that the market gives it (or doesn’t give it), but should also take into the account the non-monetary benefits and aspirations of society and include the environmental reality that we live with. Many companies often refer to this kind of holistic economic framework as their triple bottom line, which means they base their company decisions not just on increasing their profit margins, but also the impacts on people and the planet. Solely basing our decisions on economics that does not factor in the natural ecology or non-monetary benefits will inevitably produce a bruised and damaged future, as being played out in today’s world.

Although just getting going, there is incredible work going on to create an economic system that is more accountable to a sustainable and healthy society. Instead of the GDP (gross domestic product) defining the health of our economy, we should use the Gross National Happiness index; instead of economic “growth” being our mantra, it should be the level of personal and economic development and creativity. The viewpoint expressed by the water resources expert struck me as strangely antiquated in today’s world, in which the youth are coming together to demand new ways of rethinking what we value as a society and how we relate to all of our relationships.


Maceo Carrillo Martinet, PhD, is an Albuquerque-based ecologist/educator working on ecological restoration and community-based environmental education. He is on the board of the New Mexico Water Collaborative (, a group dedicated to reducing NM’s water footprint. Email:



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