Drinking water within the county is derived from private and public water distribution companies or private and public wells. Communities located in rural areas of the county are often dependent on wells for their drinking water source. The Mercer County Division of Public Health County Environmental Health Act Agency is responsible for public non-community water sources located within the county and regulations as per N.J.A.C. 7:10 et seq. These systems are required to conduct levels of water quality analysis periodically to ensure the quality of their drinking water supply. If a system does not test or the maximum contaminant levels are exceeded, the Agency takes immediate action to bring the system back into compliance to ensure the safety of the potable water source.

Testing violations and complaints are received directly from the New Jersey Department of Environmental Protection Emergency Notification Hotline, well system operators, and citizen referrals. In addition, municipal health departments, as part of their Certificate of Occupancy procedures, notify the County when they receive a request to install, modify, or change usage of these permitted public well water systems.

Additional information regarding water supply may be found at the New Jersey Department of Environmental Protection, Division of Water Supply and Geoscience.