As part of the regulatory process, the US Environmental Protection Agency (USEPA) compares the benefits of regulatory alternatives to the treatment, monitoring, and reporting costs of each alternative. The Office of Drinking Water has analyzed the combined effects of all the Safe Drinking Water Act rules to gain a national perspective and a system-level perspective. This paper presents total national, state, and system-level impacts of regulations based on a study conducted in 1988-1989. Regulations covered include fluoride, VOCs, surface water treatment rule, total coliform monitoring, Phase 2 SOCs, Phase 2 IOCs, lead and copper rule, Phase V SOCs/IOCs, arsenic, radionuclides, and groundwater disinfection. The total national cost and the timing of expenditures (which depends on compliance deadlines for various rules) are estimated. Compliance cost data are grouped by size of system. Costs to state programs in terms of staffing and funding are also discussed. Benefits of safe drinking water, including avoided adverse health effects, are discussed. Intangible benefits, such as a margin of safety, are also discussed.