Water Conservation in Commercial Restrooms

By Michael Funari, Director of Engineering / R&D

Zurn Industries Commercial Brass

Why is there so much hype about water conservation in commercial restrooms? The short answer is: Our supply of fresh water throughout the world is becoming more limited every day. Water is the foundation of life. Access to fresh water is critical for the survival of many species including humans. The human body is an amazing machine. It can survive weeks without food by pulling energy from fat storage cells, but take away water and a typical human is unlikely to survive beyond 3 or 4 days. Accessibility to fresh water on a daily basis is critical to our mere existence. Although nearly 71% of our planet is covered with water, surprisingly, only 3% of that is considered fresh water. Furthermore, two-thirds of that is locked away in glaciers and polar ice caps. Bottom line, only about 1% of the water found on Earth is considered fresh water, available for daily consumption. As the Earth's population continues to grow, we need to find ways to meet the fresh water needs.

In the U.S. alone, the population has grown by 90% over the last 50 years. During that same period, the use of water in the U.S. has risen 209%. In 2000, Americans used 408 billion gallons of water each day. With a population of 280 million, that equates to a usage of approximately 145 gallons each day per person. As that daily usage of water increases, so do the costs associated to process and deliver. Cost of water and sewer charges within the U.S. vary greatly from $3 per 1,000 gallons to nearly $15 per 1,000 gallons. So, take a median cost of $7 per 1,000 gallons. Calculate that more than 408 billion gallons per day; we spend almost $3 billion per day for water. Hit consumers in the wallet and you can usually get their attention! If we reduce our water consumption nationally by 20%, we can save about $600 million dollars per day as a nation.

Have we made a case for water conservation yet? Well, let's try another angle -- availability. EPA reports that recent surveys indicate 36 states throughout the U.S. anticipate non-drought related water shortages by the year 2013. Major cities throughout the U.S. such as Seattle have "Water Shortage Contingency Plans" in place to address the anticipated shortage issues. It's not only about availability --  it's also about the ability to deliver. Water infrastructures throughout the country are unable to keep up with demand. Further, many cities have systems that are 100 years old and exceeding their life expectancies. EPA estimates for infrastructure costs over the first 20 years of the 21st century are between $745 billion and $1 trillion. This does not include the relatively new challenges brought on with recent homeland security concerns. These hidden infrastructure costs add another $140 million per day to the daily estimates above. The California Urban Water Conservation Council has performed in depth studies that show water use efficiency programs produce a level of benefit that far exceeds the costs of the program given the alternative of investment in infrastructure. A simple review of our local newspapers and nightly news, tells us water usage restrictions are already routine occurrence for many of us. Facing the issues now will prevent today's water scarcity issues from becoming worse in the future.

This article discusses water conservation in commercial restrooms. This concept is not new, but it has taken on new life in recent years. The need for further conservation, green building movements and LEED (Leadership in Energy and Environmental Design) have been driving forces to push the water conservation envelop to new levels. The last major move regarding water conservation within the U.S. was in 1992 when the U.S. Energy Policy Act was developed. This act ensures water efficiency standards throughout the U.S. for all toilets, urinals and showerheads manufactured after 1994 (Table 1).

Today, the next generation of water conservation products are reducing water usage even further. High-efficiency toilets and urinals can be classified as follows:

High-Efficiency Toilets (HET)

• 1.28 gpf flushometer type toilets
• 1.0 gpf pressure assist toilets
• Dual-flush capability

High-Efficiency Urinals (HEU)

• 0.5 gpf flushometer type urinals
• 0.125 gpf urinals
• Waterless urinals

Many cities and municipalities are pushing legislation to mandate high-efficiency systems as the new norm. Although relatively new to the U.S. market, these fixtures are today's answer to higher levels of water conservation within our commercial restrooms.

• The 1.28 gpf toilet is a direct response to LEEDS, where 20% reduction in water consumption is important to obtain overall LEEDS certification credits.
• Recent developments within the pressures assist technology, allows us to use an air charge over water to evacuate closet fixtures with as little as 1.0 gallons of water.
• The dual-flush concept has migrated from the European and Australian markets. It gives the end user an option of full (1.6 gpf) flush for solids removal or a reduced (1.2 gpf) flush for liquids evacuation.
• 0.5 gpf urinals have been offered in the U.S. market for a few years. They allow 50% reduction in water usage from the standard.
• The 0.125 gpf urinal is fairly new to the market. It offers conventional performance at 87% reduction in water usage from the standard.
• Water free urinals have been available for a number of years. They use no water, but offer a mechanical or chemical barrier (oil for example) to allow urine to pass through but prevent sewer gasses from entering the restroom. These nontraditional fixtures have received much attention recently within the plumbing community. Careful consideration should be taken before selecting water free urinals for traditional applications.

Today, as in the early 1990s, performance is a major concern. Our industry struggled for years with the concept of acceptable water closet performance given the mandates of lower water consumption. It was quickly evident that lower water consumption with inadequate performance was simply unacceptable. It was our industry that had to deal with the customer complaints. We certainly want to avoid these issues as we push for further water conservation with today's advanced systems. So, what is performance? We all expect clean and sanitary fixtures when we enter the restroom. Simply put, the plumbing systems must work. Manufacturers focus their efforts on designing and producing fixtures that accomplish this goal. Holding the dimensional allowances from part to part and maintaining tight consistency throughout the production process is paramount. As the amount of water per flush decreases, the function of each ounce of water becomes more and more specific for proper evacuation.

To accomplish superior performance with less water, a few manufacturers have gone to a "designed system" approach. They have taken ownership of both fixture and flush valve production (Paired Performance TM). This approach ensures that the combination of fixture and flush valve are designed and developed as a system. The two work in conjunction with each other. In the past, fixtures and flush valves were manufactured by separate companies. Often, each manufacturer would focus on meeting industry test standards for performance. It was rare that communication between the two teams of engineers would occur. In many cases, the result was valves and fixtures matched in the field with less than optimal performance.

Performance, the key to further water conservation, means that plumbing fixtures perform in the real world. They must operate over a range of water pressures. Static pressure is important and in general, acceptable ranges are between 25 and 80 psi. Of more importance, is the dynamic or running water pressure. This is the water pressure within the flush valve as the valve progresses through the flush cycle. This pressure is not as easy to ensure. The configuration of the supply piping plays a big part in what running pressure is available to a given bathroom. Ensuring HET performance requires a paired performance system approach that will operate over the entire pressure range spectrum.

For a manufacturer, performance testing is imperative to bringing high quality and superior performing fixtures to the market. Two of the recognized criteria for performance testing within the U.S. are ANSI/ASME A112.19.9 Hydraulic Performance Requirements for Water Closets and Maximum Performance Testing (MaP Testing). These tests were developed to allow fixture designers and others (cities and municipalities) a way to standardize and benchmark performance. All fixtures must pass these test criteria. Constant and vigilant testing is critical to the HET/HEU success and market acceptance.

ANSI performance tests include:

• Water consumption: The amount of water consumed per flush.
• Ink-line: Test is designed to ensure proper bowl rinse.
• Dye test: Test is designed to evaluate bowl water exchange.
• Trap seal: Test to ensure the fixture fills and has proper seal.
• Ball removal: Tests evacuation.
• Granule removal: Tests evacuation.
• Line carry: Test determines how well solids are carried through the drain line.
• Splash test: Test ensures that excess splash does not occur during flush cycle.

MaP Performance Tests are designed to evaluate the evacuation properties of a given water closet or system. The test media is formulated to better resemble real world media.

As the industry progresses into the next phase of water conservation, performance and sustainability will prove to be key issues. Delivering energy and water conservation plumbing design solutions will require manufacturers to focus more attention toward the paired performance aspects of HET and HEU designs.

Illustrative example of HET / HEU savings:

The plumbing industry is providing measurable impact on water usage and conservation. For example, a typical men's restroom has four water closets and four urinals with an annual fixture usage of 25,000. The use of the 1.28 gpf HET water closets and 0.125 gpf (Pint) HEU urinals saves 119,500 gallons of water each year when compared to traditional 1.6 gpf water closets and 1.0 gpf urinals. 87,500 gallons of this water savings is realized through the urinals.