SUB-PROBLEMS INCLUDING LEADING TO IMPAIRMENT AND BEST PRACTICES FOR PUBLIC DRINKING WATER SUPPLIES
(See endnotes 1, 11)
In the United States, public drinking water systems provide drinking water for about 90% of the citizens. There are approximately 155,000 public water systems in the United States. Community water systems, which serve the same population year-round, utilize either surface water or groundwater as their source. The water, which is for human consumption, is then treated and distributed through pipes to at least 15 service connections, or an average of at least 25 people, for at least 60 days each year. A second type of water system is called non-transient, where 25 of the same people are served for at least 6 months a year, but not year-round, such as in schools, hospitals, and factories which have their own water systems. A third type of water system is a transient noncommunity water system, which provides water for campgrounds, etc. Systems are also classified by their sizes. The community water systems provide water for over 300,000. The other two systems provide for far fewer people.
All the potential pollutants discussed under General and Specific Sources of Contamination and Best Practices for Prevention, Mitigation and Control in the section above potentially apply to the surface water and even possibly the groundwater used in public drinking water supplies as the raw water source. The problems and potential contaminants found in private drinking water supplies are also found in public drinking water supplies.
In addition, there is an impact from increased urban development on water resources. The quantity and quality of the water may be affected by: the hydrologic cycle which may be disrupted; high levels of soil erosion and sediment which may be present; a reduced level of groundwater recharge; an increase in need for water for concentrated populations; and an increase in contamination from higher levels of sewage and waste disposal from these areas. Surface water used as the raw water source may also become easily contaminated by atmospheric deposition, flooding, intentional and unintentional releases of contaminants into the body of water, and municipal, agricultural or industrial wastes which are either treated or not treated, etc.