There are ten reservoirs and three aquifers utilized for tap water in all of Connecticut, although over 80% of the water in New Haven comes from four local reservoirs according to Jim Hill, the project manager of Regional Water Authority. Each plant has a slightly different treatment process, but in general the same principles apply. Water is passes through several barriers designed to prevent large items, such as logs, fish, turtles, etc... from passing through. Alum is added to the water to expedite the coagulation and sedimentation of organic particles and turbidity. This solution is given time to settle. After this stage, the water from the top of the collection chamber passes through a filtration system. Next, the filtered water is disinfected with chlorine, and fluoride and phosphate (for corrosion control) is added to the water. The water is then ready for distribution through a network of over 1,700 miles of piping. Over 110,000 tests are done on more than 10,000 water samples each year to insure high quality water is delivered to every residence and business.