Saving for a Rainy Day
An interview with Terry McMains, rainwater harvester
While Albuquerque frets about its dwindling aquifer, Terry McMains is trying to get the world, or at least the state, to listen to his solution: rainwater harvesting. McMains is not a rain farmer—he doesn’t plow through puddles, nor does he collect water in buckets. Instead, he installs high-tech rainwater harvesting systems with the company he founded, Aqua Harvest, Inc. The idea for the company was birthed when Rancho Viejo, Santa Fe’s first master-planned community with a rainwater harvesting system, was built in the late ’90s. McMains was a contractor for the project and thought he could create a company that could help alter the course of New Mexico’s water plight. Last week, he found some time to sit down with the Alibi for a chat.
Exactly how does a rainwater-harvesting system work?
Rain harvesting is defined as the act of capturing fallen rainwater from sources such as rooftops, channeling it underground and then storing it in underground tanks to be used at a later time for non-potable and potable purposes such as irrigation, flushing toilets, washing clothes, sewers and even consumption, depending on the level of filtration.
What is the difference in the levels of filtration between potable and nonpotable water?
If you are just using the water for plants, plants don’t necessarily mind if there is a little dirt in the water. Whereas, if you are planning on using it for a potable use, obviously you need to filtrate it to the point where it is safe for human consumption. And that’s just a matter of a couple of additional filters and a UV light.
Can individuals use this system? Or is it mainly for master-planned communities, businesses, etc.?
It can be used on a per-home basis, and we do a lot of custom homes. However, the most significant use is for subdivisions and master-planned communities.
What results did you see from this system in the master-planned community of Rancho Viejo?
Rancho Viejo did studies on their water consumption to see how much water these rain-harvesting systems were actually saving the community, and the results were astounding. We were able to save the community 30 percent of their fresh water usage. All we are doing is using water that’s being given to us, that we haven’t used in the past. So we are not necessarily creating new water or using groundwater more wisely, we’re using an entirely different source of water that was never utilized before. So we can reduce the contamination levels going into our fresh water supply and not have near as much of a dependency on that, because we have taken away 30 to 50 percent of the water use by using rainfall.
Would it be possible to install a system on a pre-existing house?
It really depends on the house. Retrofits are really hard because the holes that we dig are tremendously big. We are talking about a 5,000-gallon tank. That’s a huge hole. So with existing landscaping and driveways and yard walls that have to be torn down, they can be a really serious undertaking, whereas, with focusing on new construction, like new master-planning communities, it fits right in.
How big do these tanks need to be?
Depends on the size of the house and depends on the amount of water people want to save. We install systems that range anywhere from 600 gallons, which is very, very small, to tens of thousands of gallons.
How much does it cost to set up a system like this?
Anywhere from $5,000 to $8,000 per house. Depending on the tank technology we install and how the water is to be captured off the roof and how it’s going to be used. There are a lot of variables that go into what type of system we can put in.
What is the potential of this system?
[Rainwater harvesting] is something that will become common practice, because it’s something that’s common practice throughout the world. If you understand how to manage your water effectively, it completely removes the burden from our aquifers. Therefore, it saves your future. With all of the growth New Mexico is expected to experience, the demands for water can be completely relieved.
Santa Fe hired a water specialist to do some studies to see how much of an impact [rain harvesting] could really have. The results from that study were pretty incredible. The study determined that twice as much rainfall falls within Santa Fe city limits as is used by the city of Santa Fe. So, in theory, if rain was managed more effectively, Santa Fe could double in size and never touch a drop of groundwater. That’s the potential of it. That’s how much water we can save. All of the drainage issues that Albuquerque has been experiencing can be completely eliminated if we manage our stormwater more effectively. We can take it off the streets, save it, and then we have water for our future. It’s just a more advanced way of thinking.
Do you think Albuquerque has a chance of implementing these systems on a larger scale?
I think there is potential for any city west of the Mississippi that is experiencing drought conditions. It’s something that [the city] has to pay attention to, because it saves so much water. By managing stormwater more effectively, you just solved our No. 1 problem.