Turn Off the Tap: Saving H20 One Drop at a Time

It has been frequently stated that regional water shortages are inevitable in the coming years. Better understanding of the complex issues of water supply and demand, and the many choices we make that affect water resources, can help alleviate these shortages. Unlike other natural resources, water supplies are replenished naturally but often not fast enough to keep up with demand. While there is often no substitute for water, there are ample opportunities to use the water we have more efficiently. Doing so will not only help extend water supplies for human use but will also help protect aquatic ecosystems—often providing significant cost savings to homeowners, businesses and taxpayers.

Water scarcity—in your backyard?

The availability of clean, safe water is not a global issue; it is a series of very different local issues spread around the globe. Local conditions—such as rainfall patterns, landforms and plant species along with human demands for agricultural irrigation, industrial and municipal uses—determine whether a watershed is being used sustainably.

Moving water across watersheds has been going on for thousands of years, but people are now starting to understand the true costs and environmental impacts of such diversions.

Transporting water over long distances requires significant investments in infrastructure and ongoing expense for energy and maintenance. A 2009 report from The River Network estimates that 13 percent of all energy used in the United States is for pumping, heating and treating water. As greenhouse gas regulations become law in the coming years, it is clear that reducing the energy demand of water will be a key component of any climate change policy.

In addition, many of the pipes and valves that make up the water infrastructure of the United States are overdue for repair and replacement. The American Water Works Association estimates that up to US$1 trillion needs to be spent to maintain existing infrastructure in the next 20 years. While a portion of the American Recovery and Reinvestment Act 2009 stimulus funds are dedicated to this, it falls short of what is needed. Meanwhile, approximately 15 percent of all municipally supplied water leaks out of pipes before it reaches end users.

The net result of water’s scarcity, energy intensity and leaking infrastructure is that the cost of water is likely to increase significantly in the coming years.

Water efficiency—savings waiting to be tapped

Many cities now consider water efficiency to be equivalent to, but much less costly than, developing new supplies. Until recently, water efficiency projects have lacked the widespread appeal of energy efficiency savings projects because the paybacks have not been as attractive. As water costs rise and water utilities provide incentives for residential and commercial users to invest in water efficiency, these projects are getting a second look.

Water consumption varies widely between different types of buildings. In most cases, a water audit is required to understand how and when water is used in a specific building, thus helping to identify potential savings. For many commercial, industrial and institutional (CII) users, the four main uses of water include landscape irrigation, cooling towers, process equipment and plumbing fixtures. Table 1 lists some of the strategies that can be employed to reduce water consumption in each of these applications. Product manufacturers and consultants provide equipment and design support to help end users implement these projects.

In addition, many water uses in CII applications do not require potable water. Municipally supplied reclaimed wastewater, captured rainwater and graywater are alternative sources of water that can be used (subject to local codes) for landscape irrigation, cooling tower makeup water and for flushing toilets and urinals. Facility managers should check with local water utilities to determine whether non-potable water sources are available or allowed. Use of non-potable water also helps buildings earn water efficiency credits in most green building programs.

Regulating water efficiency

The need for economic growth coupled with the unsustainable use of water in many areas is leading to new regulations that affect water use. In the case of plumbing products, cities and states have already required installation of the most efficient products for new construction and major remodels. Some of these are shown below in Table 2.

Many more of these types of regulations are expected to be enacted in the coming years. Fortunately, plumbing manufacturers have responded with a range of products that meet these requirements without sacrificing performance. However, there is a physical limit to plumbing water efficiency. Sanitary systems need a minimum amount of water to transport solid waste from its source to the wastewater treatment plant. Reducing the amount of water in the system beyond what these regulations call for may degrade performance of sewer systems. At this time, it is unknown whether this will be a widespread or isolated problem, or hopefully, not a problem at all.

It is clear that in many parts of the United States water resources are not being used sustainably. Eventually, all users will be asked to make better use of water in their homes and businesses. Rising energy costs and additional funding for infrastructure repairs will drive water rates higher, while incentives from local water agencies will improve the economics of water efficiency projects.

A final caution

Many parts of the world have immediate water problems as well, both in quantity and quality. Continued growth in demand for food—especially meat—along with rapid economic development, has put an inordinate strain on water supplies throughout Asia, Africa and the Middle East. As populations grow over the next 50 years and economic prosperity drives more people to eat higher on the food chain, the need for water efficiency is going to become acute. Since we participate in a global economy, the social ramifications of this will be felt worldwide. Countries such as the United States and Canada—which overall are relatively water rich—will be expected to meet food needs of other countries, placing added strains on North American water supplies. Finally, the effects of climate change, while somewhat unpredictable locally, are expected to greatly exacerbate water issues everywhere.

About the author

Rob Zimmerman is currently the senior staff engineer for Water Conservation Initiatives at Kohler Co., in Kohler, Wisc. His responsibilities include working with government regulators and water utilities on water conservation program and code development, and supporting and growing Kohler’s line of water-efficient plumbing products.