Public Drinking Water Branch

1999 Annual Compliance Report of Missouri Drinking Water Systems


Public Water System: Annual Compliance Report Shows Significant Decrease in Bacteriological Violations

The 1999 Annual Compliance Report of Missouri Drinking Water Systems, published by the Missouri Department of Natural Resources (DNR), is now available. The report, compiled by the Public Drinking Water Program, describes the extent of violations by Missouri public water systems during 1999.

 The 1999 Annual Compliance Report

The 1999 Annual Compliance Report covers Missouri’s 2,734 public water systems. On a population basis, 96.2 percent of the 4.7 million Missourians served by community public drinking water systems received drinking water that met all maximum contaminant level (MCL) standards in 1999. A MCL is the highest level of a specified contaminant that will still be protective of public health.

The vast majority of MCL and monitoring violations were for failure to meet the requirements of the Total Coliform Rule. Total coliform bacteria serve as an indicator that disease-causing organisms may be present and all public water systems in the state must test for this type of bacteria every month they dispense water to the public.

DNR is particularly pleased to report a reduction from 1998 to 1999 in both monitoring and MCL violations of the Total Coliform Rule. Major monitoring violations declined 12 percent (from 1,140 to 1,006). MCL violations for total coliform bacteria decreased 22 percent (from 551 to 430). Acute MCL violations for fecal coliform/ E. coli decreased 48 percent (from 81 to 42). Although weather conditions may have contributed somewhat to the elevated numbers of violations in 1998, ongoing compliance and technical assistance activities by the department have largely been responsible for the reduction in violations from 1998 to 1999.

Many public water systems perform testing beyond that required by the state. A public water system, by definition, provides water for human consumption through pipes, or similar means, to at least 15 service connections or serves an average of 25 people for at least 60 days each year. Water testing at systems serving fewer people than this is facilitated by county sanitarians and the Missouri Department of Health, rather than DNR.

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 regular basis, but in a nonresidential setting.

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 report lists all systems with MCL violations and those systems with monitoring violation problems that have become chronic. Monitoring violations occur much more frequently than MCL violations. A number of systems missed collecting samples for one or two months; few systems missed sampling for three or more months. Only 83, or three percent of Missouri systems were listed on the U.S. Environmental Protection Agency’s (EPA) list of Significant Noncompliers in 1999.

For all violations, public water systems are required to notify their consumers. The method of notification varies by the violation and system type. Systems must then report back to DNR how the public notice was performed. DNR works closely with public water systems to help them remain or return to compliance in a timely manner.

The following table summarizes the violation statistics from the 1999 Annual Compliance Report.

Contaminant Group/Rule Type of Violation Number of Violations Number of Systems with Violations
Organic Chemicals Monitoring 273 13
Organic Chemicals MCL * 5 3
Trihalomethanes Monitoring 0 0
Trihalomethanes MCL * 0 0
Inorganic Contaminants Monitoring 154 14
Inorganic Contaminants MCL * 1 1
Nitrate Monitoring 70 70
Nitrate MCL * 3 3
Radionuclides Monitoring 22 22
Radionuclides MCL * 3 3
Total Coliform Rule Monitoring 1006 587
Total Coliform Rule MCL * 430 313
Surface Water Treatment Monitoring 0 0
Surface Water Treatment Treatment 20 14
Lead and Copper Monitoring 56 56
Lead and Copper Treatment 0 0
* MCL = Maximum Contaminant Level

You can receive a copy of the 1999 Annual Compliance Report of Missouri Public Drinking Water Systems by accessing the 1999 Annual Compliance Report or by writing to the address at the bottom of this page, or call 800-361-4827 or 573-751-5331.