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Ohio State University Extension


Drinking Water Regulations

Karen Mancl, Professor Food, Agricultural and Biological Engineering

Providing high quality drinking water to homes and businesses is a priority in Ohio and the nation. To accomplish this, the United States Congress first passed the Safe Drinking Water Act in 1974. The act charged the U.S. Environmental Protection Agency (US EPA) to develop national drinking water standards and establish requirements for treatment, monitoring and reporting by public water systems. The federal and Ohio regulations are constantly being updated and revised.

Public Water Systems

A public water system provides piped water for human consumption. Public water systems, by definition, serve at least 15 connections or regularly serve an average of at least 25 people at least 60 days per year. Public water systems fall into three categories:

  1. Where people live—community water systems, like municipal systems, rural water districts and mobile home parks.
  2. Where people work—non-transient, non-community water systems, such as schools, factories and office buildings.
  3. Where people visit—transient, non-community water systems, for example, parks, motels, restaurants and churches.
Very small Less than 250 people
Small 250–3,299 people
Medium 3,300–50,000 people
Large More than 50,000 people

Public water systems are also classified into four size categories. The large systems must be monitored more frequently. The smaller systems have more lenient monitoring requirements.

Public Water System Responsibilities

The owners and operators of public water systems are responsible to both the public and the state of Ohio. Local governments or private organizations that provide water to the public have several responsibilities.

  1. Obtain a drinking water license and plan approval from Ohio EPA.
  2. Hire a qualified operator. The operator must be Ohio EPA certified to operate systems serving more than 250 people.
  3. Test drinking water and report results to Ohio EPA and the customers.
  4. Notify Ohio EPA and the customers of any violations.
  5. Correct any compliance problems.

Water systems hire certified operators to test and treat water. However, the system owner is ultimately responsible for providing safe water and complying with the regulations.

Drinking Water Standards

The Safe Drinking Water Act sets requirements for treatment, monitoring and reporting by public water systems. The Act also directs US EPA to identify contaminants and set maximum acceptable levels in drinking water. The US EPA is charged with setting the national primary (enforceable) drinking water regulations to protect the public health. They also established secondary (recommended) standards for taste, odor and appearance to protect the public welfare. Figure 1 shows the number of drinking water standards and how the number has grown since 1975.  

To learn more and view and up-to-date list of drinking water standards go to

Figure 1. The number of drinking water standards public water systems must meet starting in 1975.  

Originally posted May 27, 2016.