The Water Cocktail
Do you know the difference between tap and bottled water?
Amidst rising concerns for water quality, I wanted to take the opportunity to debunk some water myths and shed some light on concerns in and around piping systems. In doing this, I had a chance to research the similarities and dissimilarities in the “tap” water industry versus the bottled water industry to find out what is really in our drinking water.
Although water is freely given by nature, water purveyors maintain and use the natural resources available in a given area. Infrastructure is in place and is continuously being improved by governmental agencies to provide facilities, which cleanse water and redistribute it for use in households and businesses. I chose the word “redistribute” because we all know of the water cycle the process of cleaning, delivering and recycling the water is an extension of the naturally occurring sequence.
The equipment and energy used to manually provide water to individual households and businesses costs money. Therefore, each establishment is charged for its usage of these services. There are precautions also required to be put in place by building owners for protection of the public water supply. Fair enough, but much to my surprise, I was having a drink of water at my desk the other day when something on the bottle caught my eye: “Source: City of Dallas.” A common misconception is that the purity of bottled water is superior. Such as in times of disaster and need, bottled water is in great demand.
What would we consider the ideal purity of water? Well, at its simplest form, H2O. Where do we find truly pure water for consumption? We don’t. Earlier I mentioned the term ‘source,’ which can be a river, lake, aquifer, spring, etc. These are all naturally occurring sources of water. The natural filtration occurs when the liquid permeates layers of earth and makes its way to aquifers or bodies of water where it is collected. The chemicals present in this source water include minerals, salts and metals. These water-soluble vitamins are commonly found in human body tissue. In the drinking water industry the broad term “dissolved solids” is used to describe the existence of these solids in the water. This is said in terms of parts per million.
In the U.S., standards and regulations are in place that govern the characteristics of water and identify safe levels of dissolved solid compounds within the drinking water. The EPA strictly governs contaminants in drinking water delivered by public water supply districts under the Safe Drinking Water Act. The Food and Drug Administration (FDA) regulates the bottled drinking water industry and manufacturers of packaged food products.
Since the source of the bottled water I was drinking began with the local municipal water supply, let’s begin with the standards regarding “tap” water. The EPA specifically monitors disinfectants used in the treatment of drinking water, as well as byproducts of the disinfection process. Many solids must be physically removed from the water using processes we will later identify. The agency also tracks organic chemicals, inorganics, microorganisms such as Legionella, E. coli and radioactive isotopes. These categories address baseline levels of dissolved solids, which are known to cause health effects.
The EPA works with municipal water purveyors to determine treatment methods dependent upon the properties of the incoming water. These levels are constantly monitored as water comes in contact with prescription medications, foods, grease and many other elements discharged into the sanitary system. Allowable limitations pass through within the customary treatment process, but constituents are required to be notified under the Safe Drinking Water Act if there are any concerns with the supplier meeting necessary water quality standards. References to current technology, current guidelines and ongoing improvements that affect greater than 154,000 districts throughout the country can be found by contacting the EPA.
It is the source itself, and also the type of water, that expresses the purity grade of a bottle of water. Since the top-selling manufacturers of bottled water in the U.S. obtain their water straight from the tap, I am using the city water supply as our example source. In the bottled water industry, the term “purified” on the label merely means the water has undergone some additional form of treatment within the bottling facility before being rationed out and labeled for individual sale. The types of treatment can fall into these categories: distilled, demineralized, deionized and reverse osmosis.
Additionally, the FDA recognizes four other types of water, including: mineral water, spring water, sparkling bottled and artesian water. Therefore, not all water is created equal. Specifically Code of Federal Regulations 21 CFR 165.110(b) establishes allowable levels of chemical, physical, microbial and radiological contaminants in bottled water, which are less stringent than current public water regulations. The agency’s purpose is to identify the water source, inspect treatment procedures and determine whether or not the bottling company analyzes their source water.
A statement on the U.S. FDA website by Joshua Sharfstein, MD, the principal deputy commissioner of the FDA states current challenges within the agency regarding regulation of bottled water contaminants include the inability to require testing results conducted by bottled water manufacturers, as the use of certified laboratories is not mandated. An interesting item to note is that many manufacturers remove dissolved solids via reverse osmosis or other processes and use additives within the final water product in order to gauge and maintain specific levels of select nutrients. The Department of Health and Human Services is currently striving to address these concerns.
Why is this information relevant? We are in the industry of designing and building these systems that distribute and purify water, which is the heartbeat of civilization. Take into consideration there is no universal standard for drinking water requirements. As recently as 1991, the European Drinking Water Directive was similarly adopted legislation in the United Kingdom under the World Health Organization, in which member states must publish drinking water reports every three years. In America, these reports are required annually. This source testing occurs at the water treatment facility and does not capture residential and commercial piping infrastructure. As we know all too well, poor infrastructure in turn affects quality of water and vice versa. On the opposite side of the tipping point, if water lacks these dissolved solids it will leach or obtain them from somewhere, i.e. metal plumbing components and pipes.
One of the most important facts to consider in plumbing engineering is the fundamental property of the water that is to be distributed. This must be inclusively engineered of the downstream discharge and pre-treatment of wastewater, as well as the requisite treatment of incoming supply water based on the system parameters. Identifying those requirements early on in a project will mitigate design issues in the future.
Lyric Lain is the first certified plumbing designer at the employee-owned, design-build company Burns & McDonnell, which is located in Fort Worth, Texas. Lain has served on the Dallas-Fort Worth American Society of Plumbing Engineers (ASPE) Board of Directors as corresponding secretary and newsletter editor. With more than eight years in the plumbing-design industry, she is currently seeking her mechanical engineering degree.