The history of recycled water’s purple pipe color

Water

A purple pipe is a clever solution to a big challenge: how to transport recycled (or reclaimed) water in a safe and efficient way. The distinct purple color isn’t just for style; this system ensures that non-potable water is safely delivered for a variety of purposes, such as irrigation, industrial processes, toilet flushing, and more. A purple pipe designation helps prevent cross-contamination while promoting water conservation in areas with high demand or limited freshwater resources. 

But where did the idea of the purple PVC pipe originate and how did it grow to become the go-to choice for water reuse? Let’s dive in!

Expanded Historical Timeline of the Purple Pipe

1960s: Early innovations

In the ’60s, when utilities such as the Irvine Ranch Water District (IRWD) began delivering recycled water to new communities, pipelines were simply marked with metal wire or tape. Around this time, discussions about color-coding utility infrastructure, including recycled water, began to take shape, inspired by existing systems used for gas, electricity, and communication lines.

Early 1980s: Recognizing the need for a standard

By the early 1980s, as recycled water usage continued to expand, the need for a standardized system became clear. During a conference in Florida, Ron Young, IRWD’s general manager, recognized the importance of a universal color code for recycled water pipelines. Inspired by the success of color-coded systems in other industries, Young challenged IRWD engineers to identify a distinct color that would symbolize recycled water and set a new standard for infrastructure management.

Mid-1980s: “Irvine Purple” is born

Keith Lewinger, IRWD’s assistant director of planning and a colorblind engineer, played a key role in selecting a color he could easily identify. He knew that if it worked for him, it could work for others.

• IRWD engineers identify a pinkish-purple shade—Pantone 240 and 241—as the ideal color for recycled water pipes.
• This distinctive purple color, nicknamed “Irvine Purple,” is chosen because other utilities had already claimed common colors: blue for potable water, green for sewers, red for firefighting, and brown for combustible fluids.

1980s: Collaboration and implementation

The IRWD soon partnered with public health agencies, the American Water Works Association (AWWA), and the Water Environment Federation to officially adopt the purple pipe standard. The unique color became integral in preventing accidental cross-connections in plumbing systems.

• In 1984, Tucson Water in Arizona launched its Reclaimed Water Treatment Plant and the Sweetwater Recharge Facility with ten miles of purple pipeline serving one customer, La Paloma, a destination golf course.
• Starting in the 1980’s, Florida’s Water Reuse Program pushed the slogan “Use it Again, Florida!”

1990s: Wider exception and adoption

The purple pipe standard gained traction as drought conditions and water scarcity increased the importance of sustainable water management.

• Washington State started using purple pipes to identify reclaimed water systems after the passage of the Reclaimed Water Act in 1992
• Starting in the 1990s, Austin’s purple pipe system has repurposed reclaimed water from sources like air conditioning condensate and washing machines for non-drinking uses, including irrigation and cooling towers.
• In 1997, purple pipes were adopted by the American Water Works Association (AWWA) California-Nevada Section.

2000’s: A new standard

More utility companies in urban areas began bringing recycled water directly to homes and businesses through purple PVC pipe systems. New applications such as landscape irrigation, toilet flushing, and industrial cooling began conserving thousands of gallons of potable water annually.

• In 2000, the San Antonio Water System completed the construction of over 80 miles of pipelines to provide reclaimed water to users in the city.
• In 2003, the purple pipe was adopted as the Uniform Color Standard of the American Public Works Association (APWA). Since then, plumbing codes have been updated to include more guidance specific to water reuse activities.
• Starting in 2004, Denver Water’s 68-mile purple pipe system began delivering reclaimed water for non-potable use to 34 parks, 9 schools, 5 golf courses, and the Denver Zoo in Colorado.
• The SB 283 Senate Bill was successfully sponsored by IRWD in 2009, paving the way for the adoption of California Plumbing Code provisions setting forth design standards for the safe plumbing of approved buildings with both potable and recycled water systems.

2010’s: Nationwide growth

• In 2012, Article 12C of the San Francisco Health Code went into effect, requiring new developments and major renovations of 250,000 square feet or more to evaluate and install onsite water reuse systems. This mandate was updated in 2021 to require onsite reuse in new construction buildings 100,000 square feet or more.
• In 2016, Florida’s Governor Rick Scott officially named May 15-21 as Florida Water Reuse Week, putting purple pipes in the spotlight. 
• In 2018, Washington State implemented regulations for purple pipes, signifying reclaimed water, with the adoption of the “Reclaimed Water Rule” (Chapter 173-219 WAC).
• In January 2017, the San Francisco Public Utilities Commission introduced the Non-potable Water Ordinance Excess Use Charge Program through Resolution No. 17-0019. 
• In April of 2024, Austin Water implemented its new GoPurple program, aimed at expanding the use of reclaimed water throughout the Austin area to promote more sustainable water practices—all while honoring the iconic purple pipes that make it possible.

San Francisco leads in water reuse policy. Spearheaded by Paula Kehoe and the San Francisco Public Utilities Commission, Article 12C requires onsite reuse systems in new buildings over 100,000 square feet. The city now has 48 operational systems, with over 1.3 million gallons of water per day expected to be reused by 2040.

Today: A global icon of sustainability

The purple pipe has become a globally recognized symbol of recycled water, often referred to as “Irvine Purple” in honor of its origins. With its bold hue and clear “Recycled Water – Do Not Drink” label, it’s a practical reminder that creativity can solve even our driest challenges.

Once a niche solution, the purple pipe now symbolizes the power of simple ideas to spark widespread change. By standardizing its use, communities have created a universal language for water reuse. As the world faces mounting water pressures, the purple pipe proves that sometimes, the answer to big problems really is hiding in plain (purple) sight.

Want to learn more about water reuse regulations across the United States? Read more here. 

Want to learn more about how onsite water reuse systems can transform your project? Read more here.

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