Oregon has 2,500 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 55 largest municipal water systems serve 80% of the population, yet 85% 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 nine 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 (OHA) to analyze their drinking water samples, and the water supplier must report the results of their required samples to OHA. Oregon water systems submit 150,000 or more compliance sample results to OHA each year.
The 2022 Oregon ACR summary table shown below presents violation data for key contaminant groups that have MCLs. "Water Quality Violation" means that the drinking water at a water system exceeded the MCL or did not properly treat the water (Treatment Technique) 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, 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 MCLs. We continue to work with all water suppliers to ensure that drinking water quality problems are identified and corrected to protect people's health.
Oregon Drinking Water Services 2022 Annual Compliance Report
Key
Contaminant
Group
| Water Quality Violations
| Monitoring Violations |
|---|
Number of
Violations | Number of
Water Systems
with Violations | Number of
Violations | Number of
Water Systems
with Violations |
|---|
Arsenic, Nitrate and Inorganic Contaminants: These combined are 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 every nine years.
Radioactive Contaminants: The three contaminants of this group, gross alpha, combined radium and uranium, are usually naturally occurring due to geology. Water systems must monitor from quarterly to every nine years.
Synthetic Organic Chemicals: This is a group of 30 chemicals, such as pesticides. Water systems must monitor from quarterly to every nine years.
Volatile Organic Chemicals: This is a group of 21 chemicals, such as degreasers and solvents. Water systems must monitor from quarterly to every six years.
Disinfection By-Products: Disinfection of drinking water, usually with chlorine, is the key means to ensure that water is safe from microbes. Disinfection of drinking water can produce by-products that must be limited to protect health. Water systems monitor from quarterly to every three years.
Groundwater Rule: This rule ensures monitoring and proper disinfection (due to source water contamination) of groundwater. When disinfection is required, daily monitoring and recordkeeping must be submitted monthly. If disinfection is applied but contamination is not present, monitoring of the groundwater source is required monthly or yearly.
Lead and Copper: EPA has established an action value for lead and copper in drinking water. Excess lead in drinking water poses adverse health effects, especially to infants and children. The most common source of lead in drinking water is from leaching household plumbing. Community and Non-Transient Non-Community water systems must monitor every six months, every year, or every three years for lead and copper. System that have installed treatment must also report monthly to demonstrate compliance with adjusting the corrosiveness of the water.
Public Notice: Water systems with water quality violations must inform consumers served and provide a copy of the notice to OHA. Due dates for issuing notices are either one day or 30 days depending on the severity of the violation. Violations occur when OHA is not given a copy of the notice by the due date.
Coliform Bacteria: Frequent monitoring is required of every water system as 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.
Surface Water Treatment Rules: These rules ensure proper filtration and disinfection of surface water and groundwater under direct influence of surface water. Daily monitoring and recordkeeping must be submitted monthly.
|
Arsenic
| 21
| 8
| 31
| 25
|
Inorganic Contaminants
| 0 | 0 | 177
| 15
|
Nitrates
| 5
| 3
| 169
| 145
|
Radioactive Contaminants
| 0
| 0
| 82
| 38
|
Synthetic Organic Contaminants
| 2
| 1
| 2552
| 107
|
Volatile Organic Contaminants
| 0
| 0
| 1355
| 63
|
Disinfection By-Products
| 20
| 8
| 123
| 53
|
Groundwater Rule
| 12
| 9
| 331
| 215
|
| Lead and Copper Rule | 22
| 19
| 375
| 212
|
Public Notice
| 0
| 0
| 57
| 43
|
Coliform Bacteria
| 49
| 47
| 1153
| 576
|
Surface Water Treatment Rules
| 65
| 24
| 626
| 78
|
Total
| 196 |
| 7031 |
|