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Drinking Water Data Management Overview
Data management plays a critical role in helping states and EPA protect public health. The Safe Drinking Water Information System (SDWIS) federal and state databases contain information submitted by states, EPA regions, and public water systems in conformance with reporting requirements established by the Safe Drinking Water Act (SDWA) and related regulations and guidance.
States supervise the drinking water systems within their jurisdictions to ensure that each public water system meets state and EPA standards for safe drinking water. SDWA requires states to report drinking water information periodically to EPA; this information is maintained in the federal database, SDWIS/FED.
A state database, SDWIS/STATE, helps states and EPA regions manage their drinking water programs and fulfill EPA reporting requirements. While a state drinking water program may use any data system they choose, the vast majority of states use SDWIS/STATE as their data management tool.
What information is included in SDWIS/FED?
States report the following information to EPA:
- Basic information on each water system, including: name, ID number, city county, and number of people served, type of system (residential, transient, non-transient), whether they operate year-round or seasonal, and characteristics of their sources of water
- Violation information for each water system: whether it has followed established monitoring and reporting schedules, complied with mandated treatment techniques, violated any Maximum Contaminant Levels (MCLs), or communicated vital information to their customers
- Enforcement information: what actions states have taken to ensure that drinking water systems return to compliance if they are in violation of a drinking water regulation
- Sampling results for unregulated contaminants and for regulated contaminants when the monitoring results exceed the MCL
EPA uses this information to determine if and when it needs address non-compliant systems, oversee state drinking water programs, track contaminant levels, respond to public inquiries, and prepare national reports. EPA also uses this information to evaluate the effectiveness of its programs and regulations, and to determine whether new regulations are needed to further protect public health.
What information is included in SDWIS/STATE?
SDWIS/STATE houses four major categories of information: inventory, sampling, monitoring, and enforcement. Inventory data include information on individual drinking water systems such as the system location, size, and population served. Sampling data include lab results for chemical, microbiological, and radiological contaminants regulated by EPA and the state. Monitoring information contains the schedule for sampling required under each EPA rule. By comparing the sampling data to the monitoring schedules and health-based contaminant levels set by EPA and the state, SDWIS/STATE can make automated non-compliance determinations for all EPA rules. Additionally, it has the flexibility to perform the same determinations for state-specific rules. The enforcement component of SDWIS/STATE allows states to track rule violations and the associated enforcement actions they take against the water systems to address the rule violations.
Through its reporting capabilities, SDWIS/STATE can help states report to consumers important information about their drinking water. In many cases, states have made this information available on the internet. SDWIS/STATE can also help states meet EPA quarterly reporting requirements to EPA for all their public drinking water systems. Note that other than the data required to be reported to EPA, data contained within a state’s SDWIS/STATE database is not available to EPA. Each drinking water primacy agency is the steward of its own data.