EPA Topics > Water > Drinking Water > Drinking Water System > Drinking_Water_System_sites.htm > Public Drinking Water Systems Programs > Water System Facts and Figures, 2001 (www.epa.gov/safewater/pws/factoids.html)

There are approximately 170,000 public water systems in the United States.  EPA classifies these water systems according to the number of people they serve, the source of their water, and whether they serve the same customers year-round or on an occasional basis.  The following statistics are based on information in theSafe Drinking Water Information System(SDWIS), for the fiscal year ended September 2000, as reported to EPA by the states. 

For more detailed statisticson public drinking water systems and violations of drinking water rules, readFactoids: Drinking Water & Ground Water Statistics for 2000(PDF file, EPA 816-K-01-004)[help with PDF files]or investigategetting access to drinking water data.


Public water systemsprovide water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days a year. EPA has defined three types of public water systems:

EPA also classifies water systems according to the number of people they serve: Number of Systems and Population Served for 2000:
(note:  populations are not summed because some people are served by multiple systems and counted more than once)Community Water System (CWS) :

Source of water:

System size:Non-Transient Non-Community Water System (NTNCWS) :

Source of water:

System size:Transient Non-Community Water Systems (TNCWS) : 

Source of water:

System size:

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