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The Value of Tap Water
An MWRA Chemist's Case Study
Massachusetts Water Resources Authority
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MWRA is pleased to present the paper "The Value of Tap Water: a Comparison of Bottled, Filtered and Tap Water Using the MWRA as a Case Study," by Judith Whittier, a Chemist at our Central Laboratory.
This paper is available in PDF and text-only formats and the abstract follows.
ABSTRACT: The tap water versus bottled water debate is active not only amongst those working in the environmental field, but in the media and community at large. With the future of the world’s water at riskcommons shared by all, how water as a limited resource is used and managed is an important issue that no doubt demands serious attention now and in the years to come. Because water quality, in terms of health safety, is a major reason why consumers choose filtered or bottled water over tap water, a more substantive discussion of some of the water quality issues that affect drinking water choice are discussed. A comparison tap water, filtered water and bottled water quality is provided which could also provide information as to how consumer could best spend their water dollars while also meeting the best interest of our environment.
Introduction
The tap water versus bottled water debate has become a popular subject in the public media of late. The cost of water is being discussed not only in monetary terms, but in context of cost to the environment. Thus, this debate supplies the consumer with important information on how best to spend their water dollars, both economically and environmentally. Because the value of this debate should not be lost to media over-marketing and advertising sound bites, which often results in consumer fatigue and trivialization of an issue, a more substantive discussion of the real value of tap water as a broader social value is merited. What we know about water is that it is not a private property.
We know from the fundamentals of hydrology that although water may be a temporary source on one’s private land where it can be accessed, the water did not originate there, nor will it stay there. If we then view water as a common resource, it is in economic terms, rival in consumption; one person’s use of the water reduces the ability of others to use it (1). In a society, this rivalry needs to be mediated and managed by setting public policy on the use of water as a commons to insure that all citizens, regardless of income, have access to water which is fundamental to our existence and well-being.
At the center of our modern economy are the ideas put forth by Adam Smith in 1776 that individuals are motivated by self interest and self gain, but —led by an invisible hand? of markets to unintentionally promote public interest. However, this laissez faire approach is not always successful and can lead to market failure, a situation in which a market fails to allocate resources efficiently. One cause for this failure is an externality, the uncompensated impact of one person’s action on the well-being of a bystander. Externalities can be negative; an adverse impact such as pollution, or positive; a beneficial impact such as research that can be used by others to cure disease (1).
An essay by Garrett Hardin, The Tragedy of the Commons, is a provocative discourse on management which builds on the ideas of William Forster Lloyd, who in 1833 introduced the parable of the commons to dispute Adam Smith’s famous idea of the —invisible hand? and its promotion of public interest. Hardin explains this parable as follows (2):
The tragedy of the commons develops in this way. Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning, that is, the day when the long-desired goal of social stability becomes a reality. At this point, the inherent logic of the commons remorselessly generates tragedy.
As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks, "What is the utility to me of adding one more animal to my herd?" This utility has one negative and one positive component.
1) The positive component is a function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly +1.
2) The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision-making herdsman is only a fraction of -1.
Adding together the component partial utilities, the rational herdsman concludes that the only sensible course for him to pursue is to add another animal to his herd. And another; and another. . . . But this is the conclusion reached by each and every rational herdsman sharing a commons. Therein is the tragedy. Each man is locked into a system that compels him to increase his herd without limit--in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.
With only 1% of the earth’s water available as consumable fresh water, the rivalry for water is not only gaining in intensity between agriculture, industry, and power producers, but between people for clean drinking water. As the World Health Organization reports, the shortage of safe and accessible drinking water is a major challenge in many parts of the world, and every year there are 1.6 million diarrhoeal deaths related to unsafe water, sanitation, and hygiene—the vast majority among children under 5. More than one billion people lack access to an improved water source (43). Therefore the management and use of the commons, this 1% of water, is ever more critical to our welfare as a world society.
In the United States, approximately 84% of the population gets its drinking water from a public water-supply system (PWS) (45), with 81% of these people serviced by 8% of the PWSs (44); this means that the majority of the people in the U.S. receive water from a PWS that supplies water to more than 100,000 people. The Safe Drinking Water Information System (SDWIS) provides data to the public about public water systems and their violations as reported to US Environmental Protection Agency (EPA) by the states. SDWIS data shows that larger PWSs, which supply the majority of drinking water, have far fewer violations than smaller PWSs, which helps support the EPA’s claim that the US has one of the safest water supplies in the world (44). Even with safe water, people in the U.S. still consumed more than 8.25 billion gallons of commercially bottled water in 2006 (40), prompting debate and criticism regarding the merits of both tap and bottled water.
The public water supplier sells service as a product: the delivery and removal of your water from the commons. The PWS believes its water is healthy and at the convenience of just turning your tap to meet all your water needs: drinking, cleaning and flushing. Although this makes public water a far better value at just fractions of a cent for a gallon of drinking water, critics claim there is a cost to this water which does not meet the public interest because of the negative impacts on health associated with treatment and distribution byproducts.
The private company has profit as its motive; it wants to sell as much product as it feasibly can in our consumer driven economy. The advertising and marketing strategy of the bottled water industry appears to be built on convincing the public that bottled water is healthier and convenient, and apparently a lot of the public agrees because it has supported this tremendous growth industry around the world (40). Although the invisible hand supposedly allows this supply and demand to reach equilibrium while the public interest is met, critics claim that the public interest is not met because of such negative externalities as plastic bottle pollution, energy consumption, pollution associated with product transport, and impact on the safe yield of water as a limited resource.
So who is right? If both suppliers provide a safe product of water, which we all know is fundamental to our health, why should we choose one product over the over? If we had a better understanding of the criticisms around this issue, could we make better decisions on how best to spend our water dollars as individuals while meeting our best interests as a public and that of our environment? It could be argued that to get the best economic and social value for a water dollar, one would have to weigh several important components:
- Water Quality
- Financial cost
- Environmental cost
- Energy cost
- Convenience
- Social welfare
Because water quality, in terms of health and safety, is a major reason why consumers choose filtered or bottled water over tap water (34,35), the focus of this paper is to discuss some of the major issues related to water contaminants as they pertain to tap and bottled water quality.
In the greater Boston metropolitan area, the Massachusetts Water Resource Authority (MWRA) in partnership with the Department of Conservation and Recreation (DCR) and the local municipalities, supplies water to 49 cities and towns (3). The NBC Today television show did a taste test survey of twelve different tap waters across the country and ranked Boston water as second best. Because the MWRA has been actively promoting drinking tap water in the media, essentially promoting a drink local campaign for a mere fraction of the cost of bottled water, it provides framework for a case study of tap water quality and cost.
Bottled water is often marketed as a natural, pure and healthy alternative. However, studies which have tested bottled water for contaminants have shown this marketing to be questionable as it pertains to water quality, and two of these studies will be briefly summarized.
To provide some comparative information on the water quality issues highlighted in this paper, a snapshot study was done on fourteen drinking water samples. Total Chlorine Residual, HPC, TTHM, bromide, bromate and an elements scan were analyzed on the samples which included water from two MWRA taps, MWRA water filtered through two different home filtration devices, and eight bottled waters. These results are discussed within this paper.
Water Quality and the MWRA
Approximately 2.5 million people in the Commonwealth of Massachusetts, or roughly 44% of the state’s population, have an average of 220 million gallons of water per day piped into their homes and industries that has originated from watersheds in western and central Massachusetts. The entire water system is, in a word, enormous. It is made up of very large water supply sources, water treatment facilities, pumping and storage facilities, over 400 miles of deep rock transmission tunnels and distribution mains, which in turn feed another 6,700 miles of locally owned water distribution pipes throughout the MWRA communities. Just in the eastern portion of this system alone, called the Metropolitan System that begins in Weston, there are approximately 4700 valves (3). That’s a lot of a lot! Boston, as one of the oldest cities in the United States, has one of the oldest public water supply systems. In 1652, the Water Works Company built a cistern and conduit to increase water supply to the growing city. The system has obviously grown! Expanding incrementally, the water supply system developed to become one of the first multi-municipality systems in 1895, first called the Metropolitan Water District, and later renamed as the Water Division of the Metropolitan District Commission (28). The MWRA, created in 1984 by the State Legislature, now assumes responsibility for this ever expanding water system (3). A fascinating part of Boston’s water history is the creation of one of the world’s largest reservoirs, the Quabbin Reservoir. The Quabbin, as it is commonly referred to, required a whole lot of taking; the acquisition of 80,443 acres by eminent domain, the relocation of six town boundaries, the obliteration of four towns (Enfield, Dana, Greenwich and Prescott), the relocation of 2500 people, and the relocation of more than 7500 bodies in cemeteries. On April 28, 1938, the state declared the four towns officially discontinued and the arduous task of removing structures began (27). The sound of woodpeckers, the nickname given to the men hired to cut down every tree with ax and saw, resounded throughout the 39 square mile area which was to become the reservoir. Capable of holding more than 400 billion gallons of water, the Quabbin took seven years to fill before finally spilling over the Winsor Dam Spillway (27), signaling the reservoir was full to capacity.
The quality of endpoint tap water is dependent upon several key factors, which pose many challenges to a PWS. They are discussed in this section as elements that contribute to the highly rated MWRA tap water:
1. Watershed protection
2. Source water quality
3. Treatment processes
4. Pipe quality of main and local distribution lines
Watershed Protection
Water in the MWRA system is derived from the Quabbin, Ware and Wachusett watersheds which feed the Quabbin Reservoir, Ware River and Wachusett Reservoir respectively. The watersheds are protected, monitored and managed by DCR. Controlling the use of land in a watershed is vital to contaminant control and one of EPA’s yardsticks for measuring the effectiveness of a watershed protection plan (3). The Quabbin Ware and Wachusett watershed have a combined DCR ownership of 43%. If lands protected by other local, state and non-profit groups are included, approximately 64% is protected. If the areas where development is regulated by the Watershed Protection Act are included, the total rises to about 75 % (3). The Quabbin Reservoir watershed alone covers 187.5 square miles, 55% of which is owned by DCR. More than 90% of the Quabbin watershed land is forested, and the non-DCR owned lands are sparsely populated and have limited agricultural sites. Such limited use contributes to the excellent water quality of the Quabbin (47). Continued watershed land acquisition is necessary to avoid longer term degradation of reservoir source water. As part of its Capital Improvement Program, the MWRA continuously provides financial assistance to DCR for the acquisition of real estate critical to the protection of the watershed throughout the three watersheds as a commitment to source water quality (3).
Source Water Quality
The Wachusett Reservoir is the last water storage site in the MWRA system before treatment and distribution. It is fed water from the Quabbin Reservoir, and indirectly from the Ware River by way of the Quabbin.
Updated January 22, 2008