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Annual Compliance Report
The federal Safe Drinking Water Act of 1996 requires that states submit an Annual Compliance Report to EPA by July 1 of each year presenting data on drinking water rule violations for the prior calendar year. States must 1) prepare the annual report, 2) make the annual report available to the general public, 3) publish and distribute summaries of the annual report, and 4) submit the annual report to EPA.

Our summary of the 2011 Oregon ACR is shown below. The summary shows the total number of rule violations reported to EPA and the total number of public water systems that had one or more rule violations during 2011 for key groups of regulated contaminants.

Oregon has 2,600 public water systems statewide that are subject to the federal safe drinking water requirements. These include cities, water districts, manufactured housing communities, schools, parks, and campgrounds. The 54 largest municipal water systems serve 70% of the population, yet 90% of the total number of water systems serve fewer than 500 people each. Federal regulations address 91 different drinking water contaminants. For most regulated contaminants, there is a Maximum Contaminant Level (MCL) established by EPA for that contaminant and an associated monitoring requirement. For a few of the regulated contaminants, EPA established Treatment Technique requirements instead of MCLs. Oregon water systems must monitor for these contaminants on specific schedules or monitoring periods that vary from monthly to every 3-9 years, and must demonstrate that the level of contaminants in the drinking water they supply is lower than the MCLs. The water systems engage private laboratories accredited by the Oregon Health Authority to analyze their drinking water samples, and the water supplier must report the results of their required samples to OHA. Oregon water systems submit a total of about 125,000 compliance sample results to OHA each year.

The 2011 Oregon ACR summary table shown below presents violation data for key contaminant groups that have MCLs. "Maximum Contaminant Level violation" means that the drinking water at a water system exceeded the MCL for a specific monitoring period. "Monitoring violation" means that sample results were not received at all or not received on time from a water supplier as required for a specific monitoring period. For each type of violation, both the total number of individual violations is listed, along with the total number of water systems that committed those violations. For detailed and current information on the drinking water quality at specific public water systems, see Drinking Water Data Online.

Most Oregon public water systems test their drinking water as required, submit the results on time, and demonstrate that their drinking water meets the maximum contaminant levels. We continue to work with all water suppliers to assure that drinking water quality problems are identified and corrected to protect people's health.

Oregon Drinking Water Services
2011 EPA Annual Compliance Report
Maximum Contaminant
Level (MCL) Violations
Monitoring Violations
Number of
Number of
Water Systems
with Violations
Number of
Number of
Water Systems
with Violations
Volatile Organic Chemicals: This is a group of 21 chemicals, such as degreasers and solvents. Water systems must monitor from annually to every 3 years. 31 systems failed to report all or part of these chemicals as required in 2011.
Synthetic Organic Chemicals: This is a group of 30 chemicals, such as pesticides. Water systems must monitor from annually to every 3 years. 22 systems failed to report all or part of these chemicals as required in 2011. Only two systems found one or more SOCs in their water at levels above the MCL.
Inorganic Contaminants: This is a group of 16 contaminants, usually naturally occurring due to geology but also including nitrate from fertilizer use. Water systems must monitor from quarterly to as infrequently as every 9 years. 24 systems found contaminants above MCLS, primarily arsenic and nitrate. 286 systems failed to monitor, primarily for the required annual nitrate sampling required of every water system.
Coliform Bacteria: Frequent bacteria monitoring is required of every water system as ongoing assurance that drinking water is free of microbes that can cause waterborne disease. Monitoring is required from every month to every quarter, with the number of samples based on the number of people served. Over half of all water system sample results statewide are for bacteria. 144 water systems identified the presence of bacteria in their water at some point during 2011, and took action to eliminate them. While 617 systems failed to submit samples at some point during 2011, 95% of all required bacteria samples statewide were submitted during the year.
Disinfection By-Products: Disinfection of drinking water, usually with chlorine, is the key means to assure that water is safe from microbes. Disinfection of drinking water can produce by-products that must be limited to protect health. Four water systems experienced by-product levels above MCLs during 2011, and 41 failed to monitor at some point during 2011.
Volatile Organic Chemicals 0 0 506 31
Synthetic Organic Chemicals 5 2 615 22
Inorganic Contaminants 61 24 366 286
Coliform Bacteria 192 144 941 617
Surface Water Treatment Rule N/A N/A 309 91
Lead and Copper Rule N/A N/A 248 158
Disinfection By-Products 11 4 99 41