Oral Health Data Glossary
What is the difference between Public Water System and Community Water System?
The vast majority of Public Water Systems in the US are Community Water Systems. The water systems tracked in WFRS are Community Water Systems as reported by the states. In a WFRS data set, the terms PWS and CWS can be used interchangeably.
Why is the state or county population reported by WFRS greater than the corresponding US Census population for the area?
Information in WFRS and MWF is reported by states to the CDC. PWS do not know the number of people they service, only the number of customers (i.e. water meters) that are connected to their system. Most PWS populations reported to WFRS are estimated based on the typical number of people served by each connection. As a result, these service populations may at times over-report an estimated population.
Why don’t indicators stratified by fluoridation status always add up exactly?
Most Fluoridated water systems in WFRS are Adjusted, Natural, or Consecutive. Other fluoridation status’ are possible, as reported in this Glossary under Fluoridation Status. For conciseness, these systems are not reported.
A public water system with fluoride adjusted to the recommended level. An Adjusted system is always designated as Fluoridated. See also Fluoridation Status.
Community Water System
A public water system that serves the same people each day
A water system that purchases water from another water system. EPA SDWIS reports all Consecutive relationships between PWS. CDC WFRS reports Consecutive relationships between systems that have a Fluoridated status as reported by the states.
Laboratory precision comparison between split sample results
A water system that has high natural fluoride levels and actively reduces the fluoride level in the water delivered to consumers. Defluoridated systems are always Fluoridated.
A water system that has fluoride at or above the recommended fluoride level which is 0.7 mg/L. The Fluoridation Status of the system can be Adjusted, Natural, Consecutive, Defluoridated, or even Variable.
The adjustment of fluoride to a level beneficial for oral health
The designation of a water system as Adjusted, Consecutive, Defluoridated, Multi-source, Natural, Non-adjusted, or Variable.
The source of fluoride in water: natural geological sources, sodium fluoride, sodium fluorosilicate, or fluorosilicic acid
Water that comes from a well, spring or other subsurface extraction of water
A sufficient number of samples reported to the CDC Water Fluoridation Reporting System were within the operating control range specified by the state
A water system that may have different sources of supply. See also Fluoridation Status.
A water system that has natural fluoride equal to or greater than the recommended level. A Natural system is always designated as Fluoridated. See also Fluoridation Status.
A public water system with insufficient fluoride for good oral health. A Non-Adjusted system is designated as Non-Fluoridated. See also Fluoridation Status.
A water system that adjusts fluoride but the PWS either did not stay within the stated operating control range or the state has not reported operational records to CDC Water Fluoridation Reporting System.
A water system that adjusts fluoride to the recommended level and has documented operating within the states operational control range.
Denotes a point-of-supply separate from other discrete sources. A point can be a well, a river or lake intake, a connection to another adjacent water system or any discrete supply of water. If a water system has two wells, it would have two points.
Public Water System
Defined by the U.S. Environmental Protection Agency as a water system that serves 25 or more persons in a day for at least 2 months of the year, or has 15 or more connections
See Split Sample
A source of water is a surface source such as a lake, river, reservoir, or groundwater sources such as a well or spring, or purchased water from an adjacent water system
Some states require periodic split sampling in which a water system will split a sample, test one part and report to the state, and the state tests the other part and compares the results to verify the accuracy of their testing method.
See Split Sample
The water system has reported a sufficient number of samples to the CDC Water Fluoridation Reporting System.
A surface source of water is a river, lake, or reservoir
Water systems that have multiple wells with different fluoride levels. May result in some neighborhoods having sufficient fluoride for oral health and other neighborhoods having insufficient fluoride for oral health. See also Fluoridation Status.
Water Source – Ground
Water extracted from groundwater sources through a well or spring
Water Source – Mixed
A public water system that obtains water from more than a single source such as groundwater, surface water, or purchasing water from other water systems
Water Source – Surface
Water withdrawn from surface sources such as a river, lake, or reservoir
Water System ID
Unique seven-digit ID assigned through the Environmental Protection Agency Safe Drinking Water Information System