Roughly 20 million gallons of water are pumped from the Lake each day to supply drinking water to about 145,000 people (or about 20% of the Basin’s population). Almost all of these people obtain their water from the 100 public water supplies that are monitored and regulated by the states and Province of Québec. About thirty-five of these are community water systems; the rest include motels, trailer parks, restaurants, and other businesses. The Federal Safe Drinking Water Act (SDWA) requires public water systems to monitor 84 potential contaminants in drinking water.
Vermont has 73 water supply systems, New York 26, and Quebec has one. The City of Burlington, VT and the Champlain Water District, which serve many cities and towns within Chittenden County, VT, are among the largest water suppliers in the Basin. Most of the Plattsburgh area uses ground water and a reservoir outside the City for drinking water (the Clinton County database of Public Water Supply Contacts includes information about Plattsburgh). The US EPA’s Safe Drinking Water Information System contains information about public water systems around the country and their violations of EPA’s drinking water regulations
Public water suppliers in areas affected by cyanobacteria (blue-green algae) have become increasingly effective in treating water. As cyanobacteria blooms increase in frequency and intensity around the Lake, municipal water suppliers have begun testing for cyanotoxins in raw and finished water when blooms are present. Cyanobacteria cells are typically removed during routine treatment by water suppliers, although the water treatment plant in Philipsburgh, Québec has found cyanotoxins present in their finished water during substantial blooms occurring over extended periods in Missisquoi Bay.
Little is known about the quality of water withdrawn from the Lake by individual homeowners. These unregulated water supplies likely have minimal or no treatment. Because they draw from the same sources as the public water systems that periodically experience water quality issues, they likely have similar levels of contamination. Untreated surface waters, including those of Lake Champlain, should never be consumed without treatment. Residents who do draw their water from the lake are advised to contact their local health department to be sure they are sufficiently treating their drinking water.
The boiling and filtering methods used by many private cottages and camps do not remove cyanobacteria toxins. Homeowners are advised to contact the state Health Department to determine how to identify cyanobacteria, how to test their drinking water for cyanobacteria toxins and if present, steps to take to prevent toxin exposure.