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As I See It

Rainwater capture next for plumbing contractors

I’ve said in this space before that it’s pretty silly that we flush our toilets and water our landscaping with drinking water. That notion is catching on as rainwater capture and reuse gains momentum.

Alternative water sources were a major topic of discussion at the recent meeting of the Green Technical Committee of the International Association of Plumbing & Mechanical Officials. The committee is tasked with the development of the Green Plumbing & Mechanical Code Supplement, the 2012 edition of which is out now.

IAPMO has experienced a flood of inquiries (pun fully intended) about rainwater capture, said Dave Viola, senior director of technical services. The latest version of the California Plumbing Code will incorporate all of the Supplement’s Chapter 5: Alternate Water Sources For Non-Potable Applications, with the usual California-specific amendments.

In addition, IAPMO is receiving inquiries from all over the country about inserting the rainwater provisions into codes and for education and training in various jurisdictions, Viola says.

Thus, Senior Editor Candace Roulo’s feature, “Tapping into a natural resource — rainwater harvesting creates niche for plumbing contractors,” is timely.

Candace notes that rainwater harvesting has been around for thousands of years. According to the ARCSA’s website,, the Old Testament mentions cisterns at least 10 times, and rainwater harvesting systems in the Middle East date to 5,000 years ago. In the United States, Native Americans and early settlers relied on harvested rainwater for drinking, and in 19th century Texas, rainwater was collected and used when wells went dry or became contaminated. We’re drinking the same water, by the way, that the dinosaurs drank. This is all we’re going to get.

Today rainwater harvesting goes beyond rain barrels and cisterns. They are plumbing systems. Candace reports on a packaged system with components that include a below-ground cistern to capture water from the rooftop drainage system for reuse in the building cooling tower or toilets; a “water management center”, which harvests and manages water for cooling tower makeup, flushing toilets, irrigation, or any non-potable use in one integrated system; and pre-engineered treatment and controls skids that are designed for flow rates ranging from 20-100-GPM. When needed by the cooling tower, the water management control system energizes the submersible cistern pump, which delivers water to the treatment skid where it then goes through two stages of particle filtration and disinfection by an ultraviolet disinfection unit. The controls platform is capable of managing stormwater flow through predictive weather modeling, using smart technology to hold stormwater during precipitation and release it after the precipitation event has passed. 

“Stormwater” might be considered what we have left after we’ve extracted all the usefulness out of rainwater. Many municipalities are requiring building owners to manage stormwater onsite rather than just sending it into the sewers.

There are many issues still to be settled. In a commercial building, the internal rainwater leaders will likely be cast iron. Would cast iron, therefore, need to comply with NSF/ANSI Standard 61 - Drinking Water System Components in order to be used for a rainwater harvesting system?

Candace came across so much information about rainwater harvesting that she had to call a halt to it for this story, but not for the topic itself. We’ll be covering rainwater harvesting both in print and online in the future. To read more about rainwater harvesting, including policy issues, please go to Candace’s Sustainably Speaking blog at

I just finished reading Sustainable Design: A Critical Guide, written by David Bergman who teaches architecture at Parsons The New School in New York City. The book is notable in that I didn’t find anything in it with which I disagree or that I think is wrong. Usually one must read a Jerry Yudelson ( book for that to be true. Bergman says that if a building owner or the local codes aren’t ready for alternative water sources, you should pipe it anyway.

“…[I]f you provide the necessary plumbing at the outset, it can be implemented by simply opening a valve when the code catches up,” Bergman says.

There are aspects to eco-design that can be implemented without affecting the look or the budget of a project, Berman writes. Practitioners who don’t include them are violating their professional responsibilities.

We believe that includes alternative water sources.

Follow me on Twitter @bobmader

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