Our drinking water is drawn from two watersheds: the Raritan and the Millstone. The Raritan River extends north almost to interstate 80, while the Millstone extends south nearly to interstate 195. That means that a raindrop falling anywhere in that vast expanse of real estate could flow downstream and eventually end up in our drinking water.
All of Princeton's stormwater runoff--from streets and rooftops--as well as its treated sewage, ends up in the Millstone River, which flows north to the Raritan. Most of the Raritan's water then flows east to the Atlantic, but some is drawn out, treated to drinking water specifications, and piped the 20 miles or so back to Princeton, where it emerges from our faucets. Water treatment consists of filtration, followed by disinfection with ozone, which kills any bacteria. Ozone is an excellent disinfectant, but because it breaks down rapidly, the water is then given a small dose of chlorine, which remains in the water during its journey to our taps.
About 5% of our water comes from wells rather than a river. The wells are located in Rogers Wildlife Refuge in Princeton, down along the Stonybrook. Every now and then, I am told, the water that flows from Princeton's taps is particularly cold and good tasting. At those times, we are receiving local well water rather than the surface water from the Raritan.
At Communiversity this year, the student organization WaterWatch had a water tasting table, where two brands of bottled water and Princeton's tap water were available for comparison in unidentified containers. Though I'm no gourmet, I found the tap water to taste as good as either of the bottled varieties.