You've heard the chatter before: New York City has some of the best drinking water in the country. Bottled water is unnecessary here, some say.

Whether you agree that the tap water tastes great, (because let's admit it, taste is subjective!), there are still some basic facts, gleaned from the 2013 NYC Environmental Protection report on water supply and quality, to know about water in NYC. And what better time than for World Water Day.

Some of these may surprise you...

1. One billion gallons of drinking water are delivered to NYC every day by the New York City Water Supply System.

2. 110 million additional gallons are delivered each day to one million people living in Westchester, Putnam, Ulster and Orange Counties.

3. NYC's surface water comes from a network of 19 reservoirs and three "controlled" lakes in a nearly 2,000 square-mile watershed, about the same size as Delaware.

4. The NYC Water Supply System is made up of three individual water supplies: the Catskill/Delaware supply,  the Croton supply and a groundwater supply system in southeastern Queens.

5. The Department of Environmental Protection disinfects its water with chlorine and ultraviolet (UV) light.

6. DEP also treats the water with food grade phosphoric acid and sodium hydroxide.

Phosphoric acid is added to create a protective film on pipes that reduces the release of metals, such as lead, from household plumbing.

Sodium hydroxide is added to raise the pH and reduce corrosivity, which also leads to a reduction in potential exposure to lead.

7. DEP has been treating its water with flouride since 1966, for "consumer dental health protection." On Feb. 14, 2012, after receiving authorization from the New York City Department of Health and Mental Hygiene, DEP reduced the target dosage.

8. Water demand is down 30% since the 1990s, despite population growth.

9. The average single-family household in NYC uses approximately 80,000 gallons of water each year.

10. Some living organisms can be found in the NYC water supply, including copepods, a crustacean that's a distant relative of the lobster.