Code-wise, debate continues about this piping. However, there is a consensus that these systems must be clearly and easily identified for human health and safety reasons.

Schematic of a rainwater harvest system courtesy of M/E Engineering, Rochester, NY.

Non-potable water sources include rainwater, reclaimed/recycled water and greywater. While non-potable water is not appropriate for human consumption, it can be used in a myriad of other applications, such as doing laundry, toilet and urinal flushing, and cooling tower make-up water.

Engineers and architects designing sustainable living and green building projects have a keen interest in utilizing non-potable water. One of the motivators for such projects is the U.S. Green Building Council (USGBC) LEED green building certification program.

There has been an increasing demand to design and build projects that, at a minimum, are LEED certified, and, in many cases, aim for LEED Silver or Gold. Under LEED 2.2 water conservation and innovative reuse were prime areas rich in LEED points. And under the new LEED 2009 (v3.0), it is weighted even more heavily.

The use of non-potable water can contribute up to 10 LEED points on a project, an astounding 25% of the points needed to achieve a LEED certified building. In fact, the number of LEED points available for water efficiency is even higher if any of these credits are deemed a regional priority by the USGBC regional council or chapter.

It is becoming clear that it is no longer enough to simply install low-flow fixtures. Substantive steps must be taken to conserve the use of potable water by the innovative reuse of gray water, the collection and use of rainwater and, in more and more communities, the use of municipally supplied reclaimed or recycled water. LEED points are awarded not only for the reduction in potable water use, but also for diversion and reuse of storm and waste water that, in conventional construction, would leave the site.

Water Efficiency is Key

Why all of this attention on water efficiency? Water supply issues are nothing new to some arid western regions, but in recent years, several major cities on the east coast have seen lakes and streams that supply municipal water treatment facilities dissipate to dangerously low levels. It is now an issue across all of the United States. In major cities we were surprised to learn that cooling tower make-up water in some cases represents the majority of water consumed in a building, so making every fixture a “low-flow” unit wouldn’t even address the biggest water user in the building.

Water supplies are finite while future demand on that water is infinite. As populations continue to grow we can’t keep using precious, treated drinking water to flush toilets and urinals, to irrigate landscapes or for other huge water consumers like cooling tower make-up that can easily use “less than potable” water. It’s been said that in future decades, the supply of clean fresh water will be far more important to the people of the earth than the supply of oil could ever be.

A number of companies have pioneered systems for the collection, filtration and treatment of water for these non-potable applications. Until recently the vast majority of this water was used outside of a structure for irrigation. Only now are we beginning to truly appreciate the benefits of non-potable water applications.

The color purple is used to identify pumps, tanks and pipes carrying reclaimed water for reuse. Photo courtesy of South Florida Water Management District.

Need to Convey Water Inside a Building

As a result, there is increasing demand to convey non-potable water inside the building by installing a separate distribution system for this water to those fixtures and applications that can use it. An engineer can now design a building and have thousands of gallons of non-potable water available for such uses.

From a codes and standards viewpoint non-potable water piping systems within a building is an area that is still under construction. There are hearings and discussions currently underway, not only in the U.S., but all around the world. One thing everyone agrees on is that non-potable water systems must be clearly and easily identified for human health and safety reasons. There must be no chance that a reasonable person would ever mistake a non-potable water supply line for a potable water line.

In areas where non-potable water systems have been in use for a substantial period of time (Europe, Australia, Canada), the universal color code for “do not drink” is purple. In the U.S., this color scheme has been adopted for PVC pipe used for the distribution of non-potable wateroutsideof a building, for irrigation and municipal reclaimed distribution systems.

The engineers that have specified these new systems for non-potable waterinsideof a building told us they have often used copper. They had the contractor paint the copper tube purple and then do some sort of field marking.

After listening and surveying engineering firms in cities big and small, the consensus was that they needed a non-potable, indoor piping system that would:

A) Meet all of the requirements and demands of the commercial domestic potable water systems that they were designing.After all, these new non-potable water systems are going to be distributing water for many of the same applications and uses that previously used drinking water and would be under the same pressures and demands as the potable systems. From a codes and standards viewpoint engineers and code officials want a piping system that was already listed as being suitable for potable water in the majority of the nation’s plumbing codes because the applications for the two systems mirror one another.

B) Be permanently and clearly marked “Non-Potable Water/Do Not Drink”.

C) Meet a 25/50 flame spread and smoke developed rating (per ASTM E 84 test protocol)so that the system could be installed in an unducted return air plenum. This would satisfy commercial construction standards.

D) Have an easy, reliable and proven installation method.

Over the past year, engineers and owners told us about a non-potable water application for which a product is needed, and no dedicated product existed. Because manufacturers are always eager to introduce groundbreaking new products, Charlotte Pipe and Foundry listened with great interest…and then developed the industry’s first CPVC non-potable water piping system (see product writeup at top right).

Usually when a new plumbing product, material or method is introduced, the manufacturer meets with architects, engineers and facility owners in an effort to convince them that they should use the new product. But in our case, the reverse happened.

Product Guide: Non-Potable Water Piping

Charlotte Pipe ReUze

Created in conjunction with Lubrizol Advanced Materials (who developed a new CPVC compound), Charlotte Pipe and Foundry recently introduced the new ReUze non-potable water piping system. This system is available in CTS sizes 1/2”, 3/4”, 1”, 1-1/2” and 2” sizes in 20-ft. lengths, and has a pressure rating of 400 psi @ 73°F. Purple in color, the pipe has two lines of type 180° apart clearly identifying the contents as “WARNING: NON-POTABLE WATER DO NOT DRINK.” ReUze is listed with NSF International and bears the mark “NSF-rw”. It is installed with low-VOC FlowGuard Gold single-step solvent cements and existing CTS fittings, including those with integral brass threads.
Charlotte Pipe and Foundry.Circle 1.

Uponor AquaPEX Reclaimed Water Tubing

Uponor introduces AquaPEX Reclaimed Water tubing, which offers all the benefits of Uponor PEX-a crosslinked polyethylene (flexiblility, durability, corrosion-resistance, 25-year limited warranty) with a layer of purple coloring to designate the tubing for greywater systems that supply non-potable, reclaimed water to laundry, toilets and irrigation systems. The tubing is listed to cNSFus-rw and AWWA C904 and is available in 1/2, 3/4” and 1” 300-ft. coils. The product uses the same ProPEX fitting technology as Uponor AquaPEX for fast, easy, reliable connections. Incorporating this tubing in greywater systems helps a building meet LEED or earn National Green Building Standard points.

Uponor.Circle 2.

Aquatherm Lilac Piping

Aquatherm, Inc., a manufacturer of polypropylene-random (PP-R) piping systems, has developed the Aquatherm Lilac piping system exclusively for applications such as toilet/drain water, rainwater collection, laundry/cleaning and irrigation. Lilac is available in dimensions from 3/8” to 12” (equivalent). It meets ASTM F2389 and CSA B137.11, and its color differentiates it from potable water. The pipe’s durable and corrosion-resistant PP-R material is fully recyclable and environmentally friendly. Like Aquatherm’s other systems, Lilac uses a heat fusion connection to create seamless long-lasting connections without the use of any toxic glues, resins or open flames.

Aquatherm Inc.Circle 3.

Cresline-West PVC Pipe

Cresline-West, Inc., offers four series of PVC 1120 pipe for reclaimed water, all of which meet ASTM D-2241. Typical applications for this pipe, which is purple in color and comes in 20-foot lengths, include commercial, agricultural and residential irrigation systems. The first series (SDR-21) comes in sizes from 3/4 to 6 inches and has a pressure rating of 200 psi. The second series (SDR-13.5) comes in sizes from 1/2 to 4 inches and has a pressure rating of 315 psi. The third series (SCH-40) comes in sizes from 1/2 to 8 inches and has a pressure rating of 200 psi. The fourth series (SDR-21, with gasket joint) comes in sizes from 3 to 8 inches and has a pressure rating of 200 psi.

Cresline-West, Inc.Circle 4.

JM Eagle HDPE Pipe

JM Eagle manufactures high-density polyethylene (HDPE) water pressure pipe for municipal and industrial water transmission systems and sewer piping systems. Available for sizes 1/2”- 63” in diameter, this HDPE pipe offers a zero leak rate, high performance, and long life expectancy. The pipe may be manufactured with the color striping to identify their application, such as purple for reclaimed water, blue for potable water and green for sewer application. Smaller size pipe (6” and under) can be extruded at continuous coil lengths by request. This pipe meets AWWA C901/C906, ASTM D2239, ASTM D2737, ASTM D3035 and ASTM F714, and is ANSI/NSF 14/61 listed.

JM Eagle.Circle 5.