a very small share of public water supply is used for drinking. According to one 2002 survey of 1,000 households, an estimated 56% of Americans drank water straight from the tap and an additional 37% drank tap water after filtering it. 74% of Americans said they bought bottled water. According to a non-representative survey conducted among 216 parents (173 Latinos and 43 non-Latinos), 63 (29%) never drank tap water. The share is much higher among Latinos (34%) than among non-Latinos (12%). The study concluded that many Latino families avoid drinking tap water because they fear it causes illness, resulting in greater cost for the purchase of bottled and filtered water. This notion is also repeated among Asians. Institutional overview Service providers EPA defines a public water system (PWS) as one that provides 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. The agency has defined three types of PWS: Community Water System (CWS): a PWS that supplies water to the same population year-round. Non-Transient Non-Community Water System (NTNCWS): a PWS that regularly supplies water to at least 25 of the same people at least six months per year, but not year-round. Some examples are schools, factories, office buildings, and hospitals which have their own water systems. Transient Non-Community Water System (TNCWS): a PWS that provides water in a place such as a gas station or campground where people do not remain for long periods of time. In 2007, there were about 155,000 PWSs in the United States, of which 52,000 CWSs. PWSs are either publicly owned, cooperatives or privately owned, serving a total of about 242 million people in 2000. EPA estimates the number of beneficiaries of community water systems at 288 million in 2007 The United States Geological Survey estimates that "About 242 million people depended on water from public suppliers" in 2000. Four thousand systems provide water in localities with more than 10,000 inhabitants, and the remaining 50,000 systems provide water in localities with less than 10,000 inhabitants. In 2000, 15% of Americans (43.5 million people) relied on their own water source, usually a well, for drinking water. Utilities in charge of public water supply and sanitation systems can be owned, financed, operated and maintained by a public entity, a private company or both can