Please read the following excerpt from The Economics of Public Issues, R.L. Miller, D.K. Benjamin and D.C. North, 16E (attached):

Chapter 5. Sex, Booze and Drugs Chapter 8. Are We Running Out of Water?

Water is a rare resource, which is one reason why states might distribute it without charging a price. Water is also frequently regarded as a public good, making it non-excludable and non-rivalrous. Many governments provide water subsidies to lower-income households in order to make it more affordable.