The Color Purple: Protecting Against Cross-Connections from Wastewater

By Don Vandertulip, P.E.
Principal, CDM

Many individuals who follow industry developments are aware of revisions to the Uniform Plumbing Code (UPC) published by the International Association of Plumbing and Mechanical Officials (IAPMO) (see my 12.08 blog for background) that now require use of purple pipe on private property plumbing to convey any non-potable water. The International Plumbing Code (IPC) distributed by the International Code Council (ICC) has similar requirements. WEF’s primary objection to use of purple pipe for onsite non-potable water is the risk to the public through exposure to untreated water. A secondary concern is loss of public confidence in the highly treated reclaimed water distributed in purple pipe by municipal utilities. (Read about recommendations and a letter to IAPMO.)

Simply put, cross connections between a potable water system and any non-potable water supply places the public at risk. The potential for cross-connections with multiple onsite coded non-potable pipe systems proposed by IAPMO could result in a more serious cross connection with the potable water system. I caution all professionals not to think of the onsite alternate piped water as non-potable water but to treat it as wastewater, which includes graywater as it’s generally defined -- all wastewater generated onsite except toilet waste. In many jurisdictions, graywater excludes kitchen sink and dishwasher washwater due to the high organic content of food waste. The key word is "wastewater". In most cases, graywater is not treated though there may have been a lint filter originally provided.

In addition to the potential cross connection of one or more onsite wastewater sources with the potable water system, there is potential for contamination of the highly treated municipal reclaimed water system. Contamination of a municipal reclaimed water system by one of the onsite wastewater systems could result in exposure of individuals with incidental contact to reclaimed water of impaired quality. This exposure could result in illness, even if the reclaimed water were not ingested. Degradation of the reclaimed water quality could also negatively impact other municipal reclaimed water users and violate the user agreement between the utility and customer. I suggest that the untreated wastewater proposed for recirculation and use onsite without treatment does not yet rise to the caliber of "non-potable" until it has received enough treatment to transition from its wastewater designation. In short, distributing wastewater onsite in a purple plumbing pipe will eventually cause significant damage to our collective reclaimed water programs and jeopardize public health.

Protecting Our Purple Pipes

By Don Vandertulip, PE
Chair, WEF Water Reuse Committee

I’ll start at the beginning of this important issue, which is ultimately about organizations working together to protect public health and sustainable water supplies. Purple is the standard color for pipe adopted by the international utility industry to distribute municipally treated reclaimed water. In late June 2008, a question was raised alerting water reuse professionals to a proposed plumbing code that would require use of purple pipe for all graywater systems. The proposal was embedded in updates to the 2009 Uniform Plumbing Code under final development by the International Association of Plumbing and Mechanical Officials (IAPMO) and the indication was all reuse organizations had approved it. IAPMO used the Canadian CSA B128 Design and Installation of NonPotable Systems as a guide to coordinate with international standards.

Utility members and reuse professionals at the Water Environment Association (WEF), the American Water Works Association (AWWA) and the WateReuse Association (WRA) were not aware of this proposed change, and they responded—along with several state health departments—based on a three-decade history of distributing high-quality reclaimed water through purple pipe and gaining public support for highly treated reclaimed water. Their concerns included:

• Potential cross connections between two purple pipe systems with significantly different quality;


• The public could be exposed to inadequately treated water in a municipal purple pipe system contaminated by an on-site cross connection; and,


• Public exposure and cross connections would negatively impact public confidence in the municipal reclaimed water system.

Based on this feedback, a joint letter signed by Executive Directors of WEF, AWWA, and WRA was submitted to IAPMO on September 24, 2008. I believe this letter represents the first letter endorsed by the three organizations in a common effort to eliminate a public health threat. In a separate action, Florida Department of Health (FDEP) sent a letter protesting the proposed Code.

Discussions at WEFTEC.08 among representatives of IAPMO and all three water groups regarding Code revision revealed that the issue included not only on-site graywater systems but also other sources of alternate water to include rainwater harvested water, stormwater, and air conditioning condensate and showed that other entities unfamiliar with reclaimed water production might influence its use, distribution, and quality.

Based on all of the input they received, IAPMO formed a Task Group to review the proposed code requirements and to develop alternative code requirements acceptable to plumbing code inspectors and municipal utility providers. I was appointed to this committee to represent WEF and WRA, while Alan Rimer, Chair of the AWWA Water Reuse Committee will represent AWWA.

The bottom line is that technical solutions will be developed for consideration by both reclaimed water utility interests and plumbing code enforcement officials. Water utilities and professionals have done a good job of “branding” purple pipe and educating constituents within the immediate service area about the value of reclaimed water use to the community. It is now apparent that water professionals, utilities, and state health departments must become more involved with local, state and national building code development to ensure that highly treated reclaimed water protects public health and guards against public exposure to inadequately treated alternate waters originating from on-site treatment units. I believe this increased involvement should include:

• Improved communications between IAPMO and professionals from the water field by providing technical presentations to educate each other about their respective approaches to public health;


• Improved education within our own house-including utility, health and environmental department professionals so we can recognize well-intended efforts by others that may impact the value of our purple pipe liquid assets;


• Evaluation, by utilities, of state and local regulations that may be in conflict with the Plumbing Codes adopted by the local communities and direct communication with the state entities to provide clear regulations protective of public health without causing regulatory conflict; and,


• Identification of additional common code/public health concerns related to use of non-potable water on property also served with potable water that should be mutually addressed.

The IAPMO Task Group and greater utility awareness are good starts. It is incumbent on all water utility professionals to work toward improved recognition of design controls and regulations that are supportive of public health and sustainable water supply solutions. Meanwhile, I’d invite you to visit www.iapmo.org to learn more about this important code development organization and watch for further developments as we all work together for a cleaner environment.