Editors' Summary: Public water systems that serve residential communities have been subject to the Environmental Protection Agency's comprehensive regulatory program under the Safe Drinking Water Act since the Act was passed in 1974. EPA has recently extended the coverage of its regulatory program to public water systems that do not serve residential communities, such as industrial and commercial facilities and schools. Many corporations that provide water to employees and other members of the public are thus now subject to substantial new liability. The authors examine how the new SDWA regulatory program affects corporate water suppliers. They observe that the new regulatory requirements could also serve as the legal basis for toxic tort suits for damages caused by water supplied in a corporation's facility. The authors conclude that corporations can minimize their liability by monitoring the regulatory developments and determining which requirements apply well ahead of compliance deadlines. Corporations should also evaluate the integrity of their water systems, select a high-quality laboratory to test their drinking water, and develop a compliance plan for each of their facilities.