Robert Morgan, PhD, PE
May 5 through 11, 2019 is celebrated by the American Water Works Association (AWWA) as National Drinking Water Week. The AWWA is made up of over 51,000 professionals from the water sector in America. They are considered to be the go-to source for information on drinking water.
Most of us in the United States and Canada, don’t think much about our drinking water. We go to the tap, give it a turn, and safe, healthy water magically comes out. Surprisingly, those of us in the US turn that tap to the tune of about 80 gallons per day. For a family of four, that means 320 gallons or 2,700 lbs. of water are delivered to our door every day. The cost of that service is on average across the U.S. a bit under $2 per day (https://www.statista.com/statistics/720418/average-monthly-cost-of-water-in-the-us/). Where else can you get over a ton of material delivered to your door for less than $2. To fully appreciate our amazing water delivery system, it might be beneficial to look back at the history of water distribution over time.
One of the earliest well documented water systems was on the island of Crete in the Mediterranean Sea. The Minoans developed water collection and distribution systems as early as 2000 BCE. These systems consisted of rainfall harvesting, cisterns, aqueducts, filtering systems and terracotta pipes for distribution of water and fountains (http://worldwatermuseum.com/the-evolution-of-water-supply-technologies-in-ancient-crete-greece/). Water flowed under the force of gravity down from the source into the cisterns and out into the distribution system. The system was very resilient. Remnants of the piping and cisterns can still be seen on the island today. Most of the time, water was not delivered to individual homes, but to central water stations convenient to homes. Filtration and settling provided for clear and relatively odor free water. The Minoans also had common toilets and sewers to carry waste water away from their cities.
Ancient Rome carried water distribution to the next level. Water for Rome was collected in the mountains around the city and delivered to the city in the famous aqueducts. The first aqueduct was the aqua appia built in 312 BCE. The aqua appia was almost entirely underground. Water flowed entirely by gravity from the source to the city. When water arrived at the city, it was deposited in a central tank or castellum. From the castellum water was then delivered through underground pipes to baths, fountains, water basins and even some individual homes (https://www.pbs.org/wgbh/nova/lostempires/roman/watering2.html). Much of the piping in Rome was made of lead. Lead is no longer used in water piping because of the potential public health impact. Some have hypothesized that lead in the drinking water lead to a loss of mental acuity and ultimately to the downfall of the empire. But the evidence does not support this theory. In Rome, the source water had a high hardness and water was constantly flowing. Leaching of lead out of the pipes into the water was not a problem in that situation. Waste water was allowed to overflow into gutters and channels and flow off into the Tiber River and out of town. Luckily the discharge point was downstream of the intakes.
While the Minoans and Romans were concerned about water quality. The Roman Vitruvius (http://www.romanaqueducts.info/picturedictionary/pd_onderwerpen/quality.htm) recommended criteria such as examining the health of local residents before selecting a source of water, looking for stains when a drop is placed in a brass pot and finding how quickly vegetables boiled. However, they did not fully understand the potential for water borne disease. They did know however that clean, healthy water was essential to their well being as well as the resiliency of their society. Primarily they tried to get water that was clear and odor free. Both the Romans and the Minoans used settling tanks in their systems. These tanks provided for settling of solids from the water and resulted in a clearer product. They did nothing for removal of pathogens.
Not much progress was made in water distribution nor treatment between the fall of Rome and the industrial revolution of the 18th and 19th centuries. As a result of the industrial revolution, many people moved into cities for work in the new factories. Imagine a city of several 10’s of thousands, mostly living in wooden structures and mostly using wood or coal fires for heat and energy. Fire was the major public health hazard of the time. City leaders recognized the need for improvement and began developing piping systems to bring water into town to be available to fire fighters. Drinking water came along as a secondary consideration. Many of these water pipes were made of wood. When a fire broke out, the fire company would dig up the pipe, hack a hole in the top and pump water until the fire was under control. Afterward, they made a plug and drove it into the pipe to stop the flow of water. Hence we now have ‘fireplugs’ scattered about our water systems (http://www.firehydrant.org/info/hist-fp.html). Fire fighting is still a major factor in design of water distribution systems.
During the industrial revolution, water quality when it was considered at all was determined by clarity and lack of odor. Some cities did put in slow sand filters to help clarify source water (http://historyofwaterfilters.com/water-filter-technology.html). Paisley, Scotland is generally thought to be the site of the first filtration plant in modern times. The concept of water borne disease was still several decades away. While Typhoid Fever and Cholera were common diseases, but most of the medical profession thought disease was caused by bad air or miasmas not contaminated water.
Dr. John Snow was likely not the first physician to conceive of water borne pathogens, but he was the first to demonstration the potential. During 1853 and 1854, London, England was suffering from an epidemic of Cholera. Dr. Snow suspected a source could be found that was contaminated by the Cholera bacterium. He studiously mapped cases of Cholera across the city along with where the patients got their drinking water. In almost all of the cases, the source was a hand pump on Broad Street. Dr. Snow removed the handle and locked the pump. The Cholera epidemic quickly died out (http://sphweb.bumc.bu.edu/otlt/MPH-Modules/PH/PublicHealthHistory/PublicHealthHistory6.html).
Dr. Snow’s evidence was impressive, but it took a couple more decades before the medical profession was willing to give up their theory of miasmas. Slowly they came around and accepted water borne pathogens as a source of disease such as Typhoid and Cholera. Then in 1908, Jersey City, NJ installed chlorination on its water treatment plant to kill pathogens that might be in the water. Basically, it was less expensive to chlorinate the water than to go out and find a new, less contaminated source. Other utilities in the US quickly followed suit. By the 1950’s, water borne disease was virtually eliminated in the US (https://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm).
Drinking water in the U.S. is now delivered efficiently, economically, clean and disease free to over 90% of all Americans. The Center for Disease Control considers control of infectious disease through provision of clean water and sanitation to be one of the 10 most significant achievements in public health from the 20th. century (https://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm), So we can rest tonight knowing that our water supply will help to keep us healthy. But the job is not yet over. Sources of drinking water are under pressure from many sides. Over use, quality degradation, potential chemical spills, and nonpoint source pollution all can impact water safety. For the Romans, source water protection meant finding a more remote source and posting Legion along the aqueduct incase the Huns invaded. Today, a site more remote from one city is just closer to another. We have to take care of what we have. In South Carolina, the Anderson Regional Joint Water Systems’ Source Water Protection Program has a vision of 220,000 source water protectors in their watershed. The implication is that every resident of the watershed has a role. Arkansas needs to generate a 3 million source water protectors.