Energy & Environment

The Power of Purple Pipes

You may have never thought about the color of your pipes. You might even think the topic is so mundane that no one could possibly...
by | April 30, 2009

You may have never thought about the color of your pipes. You might even think the topic is so mundane that no one could possibly care about it. Dave Viola knows otherwise.

Viola heads up the sustainability efforts of the International Association of Plumbing and Mechanical Officials (IAPMO). In that role, he's been forced to moderate a surprisingly contentious question: Just what sort of water should go into a purple pipe?

IAPMO produces the Uniform Plumbing Code, a document that many state and local governments use as a model when they approve their own plumbing codes. That role makes IAPMO an authority when it comes to the color of pipes.

Plumbers rely on coloring to distinguish between pipes that serve different purposes. For years, purple pipes have been designated for what's known as "reclaimed water." Reclaimed water is wastewater that, after being processed through a water treatment facility, is reused for not-potable purposes such as crop irrigation or watering golf courses. Purple pipes are so closely associated with reclaimed water that it has come to be known by a different name: purple water.

Much to the chagrin of reclaimed water's supporters, IAPMO's 2009 code says that purple pipes aren't just for purple water anymore. Grey water will now run through purple pipes too. Grey water is used household water from showers, sinks and washing machines-anyplace other than the toilet, kitchen sink or dishwasher. It, like purple water, isn't safe to drink. In most homes, grey water goes straight down the drain. But, with some creative plumbing, it, like purple water, can be used for watering trees and gardens.

Despite the similarities, some people feel quite strongly that the two types of water shouldn't run through the same color of pipes. "Be aware!! The proponents of using purple for all non-potables have only just begun," warned a posting from "waterbuffalo" on the Alliance for Water Efficiency's message board. "They have made their intentions clear: they want all non-potable water identified exactly the same (purple) no matter what the chemical and biological hazards. Now are you ready to fight on this issue?"

Why would anyone want to fight over pipe colors? Don Vandertulip can explain. He's president of the Texas chapter of the Water Reuse Foundation, a group that promotes reclaimed water. Vandertulip says that purple water proponents have worked diligently to convince the public and state regulators that their product is safe. But now, he says, their brand is being diluted by a type of water that never gets cleansed at a water treatment facility. If someone gets sick from grey water in a purple pipe, purple water could end up taking the public relations hit. "One small incident," he argues, "and it make take years to regain the public trust."

This debate over pipes reflects a deeper divide. Grey water is a cause for do-it-yourselfers across the country. They believe that they can save water, energy and money themselves, by reusing their own water. Purple water proponents, on the other hand, think that water utilities can most intelligently reclaim water and send it where it's needed most. They believe that professional water treatment is the only safe way to go.

It's state and local government officials that are caught in the middle, trying to decide just what the rules for water reuse should be. Municipal officials in Phoenix promote purple water, not grey water. In contrast, in Tucson plumbing for grey water reuse will soon be mandated in all homes.

Surprisingly, though, some grey water supporters agree with their purple water counterparts that grey water shouldn't be in purple pipes. Art Ludwig, a grey water guru from California, complains about the piping decision. He argues that rather than creating prescriptive rules, states should follow Arizona's lead. That state allows small-scale grey water systems without permits, so long as they meet performance standards.

So why did IAPMO make the decision? Previously, grey water was designated for specially labeled yellow pipes. But that, Viola explains, was a safety risk because yellow is usually used to designate gas lines. Grey was out, since that color indicates electrical conduit. In fact, Viola says, every other color was taken for one thing or another.

Surely, IAPMO could have come up with a creative solution. Polka dot pipes? Striped pipes? Plaid pipes? However, grey water reuse remains rare, since most states only allow it under stringent rules. The economics of pipe manufacturing make it undesirable to produce a color of pipe without strong demand. As a result, IAPMO decided that both grey water and purple water should flow through purple pipes.

While that's the rule for 2009-which states and localities can choose to adopt or ignore-IAPMO is reassessing the decision. Viola worries that if he can't reach a consensus, battles over pipe colors will spill over into state legislatures. "On the surface it seems like an innocent little issue," he says, "and when you dig a little deeper it's a serious, serious thing."

Josh Goodman
Josh Goodman  |  Former Staff Writer

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