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Water: Source Water Protection

Basic Information

Source water is untreated water from streams, rivers, lakes or underground aquifers that is used to provide public drinking water, as well to supply private wells used for human consumption. Some water treatment is usually necessary, so public utilities treat most of the drinking water before it enters the home. However, the cost of this treatment, as well as the risks to public health, can be reduced by protecting source water from contamination. EPA, other federal agencies, states, local communities, businesses and citizens all play a role in ensuring that drinking water is protected.

Source Water Assessments

To give water utilities and community members the information they need to decide how to protect their drinking water sources, the Safe Drinking Water Act requires that the states develop EPA-approved programs to carry out assessments of all source waters in the state. The source water assessment is a study that defines the land area contributing water to each public water system, identifies the major potential sources of contamination that could affect the drinking water supply, and then determines how susceptible the public water supply is to this potential contamination. Public utilities and citizens can then use the publicly available study results to the take actions to reduce potential sources of contamination and protect drinking water.

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Roles in Source Water Protection

EPA works with state and tribal agencies, non-governmental agencies and citizen groups to encourage partnerships and provide information for carrying out source water protection actions. The Agency identifies federal tools, including those available under the Clean Water Act, other EPA programs, and various agricultural programs, that can be used to help protect drinking water. EPA also works with national non-governmental organizations throughout the country, including the American Water Works Associations, the National Rural Water Association, the Ground Water Foundation and the Trust for Public Land.

State and local governments and water utilities play a critical role in protecting source water because protective actions must be tailored to unique local situations. A variety of programs fund source water protection activities at the local, state, and federal levels. The states have now completed source water assessments for all public water systems and are developing strategies to help local communities use the information obtained from these assessments. States also can provide the resources to help fund local protection activities such as wellhead protection programs for ground water and watershed management programs for surface water. Localities can develop zoning requirements to ensure that businesses using hazardous materials are not located near water supplies and can protect land in the source water area from development through acquisition or conservation easements.

Businesses and individuals can also take actions to protect drinking water sources. Businesses can institute management practices to reduce their use of harmful contaminants or ensure their wastes do not discharge into ground or surface water. Individuals can reduce their use of pesticides and ensure that their septic systems are property maintained. This is particularly important for those individuals who obtain their drinking water from private wells and must rely on ground water free of contamination.

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Local Drinking Water Information

Since passage of the Safe Drinking Water Act, our nation has enjoyed one of the safest and cleanest supplies of drinking water in the world. Protecting water at the source is the first critical step in a multiple-barrier approach that also includes treatment for contaminants, monitoring to ensure that health-based standards are met, and adequate infrastructure maintenance, especially of distribution pipes that carry water from the treatment plant to customers. An informed public with an understanding that everybody plays a role in water protection is critical to protecting our drinking water now and for the future. EPA encourages all to learn more about actions they can take to protect drinking water.


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