WQD | Public Water System

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Safe Drinking Water Section

Public Water Systems

Revised On: Sep. 9th, 2024 - 02:17 pm

Revised On: Aug.27, 2024 - 6:00 p.m.

The term public water system (PWS) refers to any water system that has 15 or more service connections (hook-ups) or serves 25 or more people. Water systems that serve less than 15 service connections or 25 people are considered private water systems and are not regulated by ADEQ. However, there are resources available to owners of private wells and these non-regulated systems.

Public water systems can be run by cities or towns, by federal or state agencies, by other political subdivisions like water districts and co-ops, or by private, for-profit companies. Regardless of the ownership, these systems must comply with all requirements of the Safe Drinking Water Act.

Categories of Public Water Systems

A "community water system" is one that serves 15 or more service connections used by year-round residents or that serves 25 or more year-round residents who use water for drinking, cooking, bathing and cleaning. Community water systems may also serve all the businesses and other water users within their boundaries.

A "non-transient, non-community water system" is one that serves 15 or more service connections that are used by the same persons for at least six months per year, or serves the same 25 or more persons for at least six months per year. These water systems supply businesses where people may spend a large percentage of time, but these typically aren't a consumer's primary water source. Examples include schools and hospitals.

A "transient, non-community water system" is one that serves 15 or more service connections, but does not serve 15 or more service connections that are used by the same persons for more than six months per year; or one that serves an average of at least 25 persons per day for at least 60 days per year, but does not serve the same 25 persons for more than six months per year. Examples include businesses where the average person will not be drinking the water for long periods of time, such as truck stops, restaurants or campgrounds. Because of the short exposure times involved, typically these systems only monitor for acute contaminants such as nitrates or bacteria.

Revised On: Sep. 9th, 2024 - 02:17 pm

Community and non-transient, non-community water systems make up the majority of the water systems in Arizona.

Although ADEQ does not regulate private wells, the department encourages well owners to educate themselves about water quality and drinking water health issues. Well owners should investigate adjacent land uses and local geology to determine if any contaminants could be affecting their well. Private well owners are strongly encouraged to collect periodic water samples to test for bacteria and other contaminants. The Arizona Department of Health Services Environmental Laboratory Licensure Program provides information about laboratories certified to perform drinking water analysis and their procedures.

Information About Your Drinking Water

There are several tools available to help you understand the quality of your drinking water if it is provided by a regulated public water system:

An interactive map is provided by the Arizona Department of Water Resources, which can help you identify if your water comes from a regulated community public water system. Note that you may receive your drinking water from a non-community water system or an unregulated water system, which would not appear on this map | Access Map >

ADEQ also maintains the Safe Drinking Water Information System (SDWIS) database, which provides contact details, water quality results, and violations for all regulated public water systems in Arizona | Access Database >

Questions, comments, concerns and/or edits regarding SDWIS?

Contact a Compliance Assistance Coordinator (CAC) | View CAC List >

Community water systems are also required to provide annual consumer confidence reports to their customers. Consumer confidence reports contain information about water sources, water quality testing, and other issues. Please contact your public water system to obtain a copy of the most recent report. 

Revised On: Sep. 9th, 2024 - 02:17 pm

Concerns About Your Drinking Water

If you are experiencing any issues with your drinking water, please first contact your public water system directly. ADEQ provides a listing of current water issues that require public notice | Learn More > 

You may also submit a complaint to ADEQ about issues you are experiencing with your drinking water using our online form | Access Form >

If your drinking water does not come from a regulated public water system but instead comes from a shared or private well with less than 15 service connections or serving less than 25 people and you have questions, please contact the Office of Environmental Health at the Arizona Department of Health Services (AZDHS). For more about private wells, visit the AZDHS website | Visit Site > 

Public Water System Requirements

Regardless of the ownership, public water systems must comply with all requirements of the Safe Drinking Water Act (SDWA) and applicable Arizona laws. ADEQ is the primary agency within Arizona for regulating public water systems | SDWA Laws > | Arizona Laws >

Regulation of Drinking Water 

ADEQ oversees all aspects of the state’s safe drinking water programs with the exception of tribal lands, which are regulated by the U.S. Environmental Protection Agency (EPA). ADEQ works closely with two of Arizona’s most populous counties to administer the provisions of the Safe Drinking Water Act and Arizona’s drinking water rules. Maricopa County’s Drinking Water Program and the Pima County Health Department manage inspections, engineering plan reviews, and compliance and enforcement activities for all public water systems in their respective counties with ADEQ’s supervision | Learn More > 

Laura Carusona
Ph: 480-612-5686
Email >