Public Drinking Water Branch

2004 Annual Compliance Report of Missouri Drinking Water Systems

Tougher standards lead to more violations

The Annual Compliance Report of Missouri Drinking Water Systems for 2004, published by the Missouri Department of Natural Resources (DNR), is now available. The report, compiled by the Water Protection Program, describes the extent of violations by Missouri public water systems during 2004.

The 2004 Annual Compliance Report

This report covers Missouri’s 2,700 public water systems. Overall, the number of violations by Missouri’s public water systems remained fairly constant from 2003 to 2004. The percent of population served by community water systems in compliance with all health-based standards stands at 93 percent, slightly below the U. S. Environmental Protection Agency’s target of 95 percent compliance by 2008. This is the first time since the department began producing Annual Compliance Reports in 1996 that the compliance rate has fallen below the 95 percent target.

The most significant change from 2003 to 2004 was the number of Maximum Contaminant Level (MCL) violations for two groups of chemicals: haloacetic acids and trihalomethanes. These are part of a larger group called disinfection byproducts and are regulated under the Disinfectants/Disinfection Byproducts Rule. In January 2004, surface water systems that serve less than 10,000 people were required to meet new standards for these chemicals. This new requirement resulted in 38 chemical MCL violations, increasing the total number of chemical MCL violations from three in 2003 to 43 in 2004. This does not, however, reflect a reduction in water quality, but is a result of more stringent drinking water standards.

The impact of more sensitive testing methods for coliform bacteria continues to keep the total coliform Maximum Contaminant Level (MCL) violations higher than historical levels. The number of total coliform violators and acute coliform violators increased in 2004. MCL violations for total coliform bacteria increased two percent and acute MCL violations for fecal coliform/E coli increased 29 percent. Major monitoring violations of the Total Coliform Rule, however, has decreased by 12 percent.

Many public water systems perform testing beyond that required by the state. A public water system, by definition, provides water for human consumption to at least 15 service connections or serves an average of 25 people for at least 60 days each year. Water testing for smaller systems serving fewer people is done by county sanitarians and the Missouri Department of Health and Senior Services, rather than the Department of Natural Resources.
There are three basic types of public water systems. The first is a community system, where people live and consume the water on a daily basis. A community system could serve the residents of a large city, rural water district, or a small mobile home park or subdivision. The second is a non-transient, non-community system, such as a school or factory, where people drink the water on a daily basis, but do not reside there. The third is a transient, non-community system, such as a restaurant, resort or campground that would not be a regular source of drinking water for most of its pass-through customers.

The Annual Compliance Report lists all systems with MCL violations and chronic monitoring violators of the Total Coliform Rule. A number of systems missed collecting samples for one or two months; few systems missed sampling for three or more months. Only 170, or 6.3 percent of Missouri systems were listed as Significant Noncompliers for 2004.

For all violations, public water systems are required to notify their customers long before the department issues the Annual Compliance Report and community systems send out their Consumer Confidence Report. The method of notification varies by the violation and system type. Water suppliers must then report back to the department how the public notice was done and provide a copy for the system’s file. When problems are found, the department works closely with public water systems to help them return to compliance in a timely manner. The following table summarizes the violation statistics from the 2004 Annual Compliance Report.

Contaminant Group/Rule Type of Violation Number of Violations Number of Systems with Violations
Organic Chemicals Monitoring 42 2
Organic Chemicals MCL * 1 1
Disinfection By Products Monitoring 0 0
Disinfection By Products MCL * 38 20
Inorganic Contaminants Monitoring 33 3
Inorganic Contaminants MCL * 3 2
Nitrate Monitoring 24 24
Nitrate MCL * 1 1
Radionuclides Monitoring 0 0
Radionuclides MCL * 34 19
Total Coliform Rule Monitoring 846 460
Total Coliform Rule
(acute and non-acute)
MCL * 526 336
Surface Water Treatment Monitoring 0 0
Surface Water Treatment Treatment 14 13
Lead and Copper Monitoring 171 169
Lead and Copper Treatment 1 1
Consumer Confidence Report Reporting 623 328
* MCL = Maximum Contaminant Level

You can receive a copy of the 2004 Annual Compliance Report of Missouri Public Drinking Water Systems by accessing the 2004 Annual Compliance Report or by writing to the address at the bottom of this page, or call 800-361-4827 or 573-751-5331.