Protecting Public Health and the Environment.

Idaho Environmental Guide for Local Governments: Drinking Water

DEQ's Drinking Water Program protects public health by requiring that drinking water from public water systems meet all health-based water quality standards and requirements of the Safe Drinking Water Act (SDWA). About 1,960 regulated public drinking water systems operate in Idaho. Public drinking water systems (publicly or privately owned) serve at least 25 people 60 days out of the year or have at least 15 service connections. Many other Idaho citizens get their drinking water from private wells. These private wells are not regulated under the SDWA; well owners are personally responsible for ensuring their water is safe.

Why Communties Should Care

If a city, district, or other entity owns and operates a public drinking water system, it is responsible for producing safe drinking water, thereby protecting the health of its citizens and fulfilling the requirements of the SDWA and other state and federal rules and requirements.

Drinking water supplies are often vulnerable to contamination from land use practices (such as farming and urban development) and potential contaminant sources (such as gas stations) within the vicinity of drinking water wells and intakes, particularly surface water intakes.

What Communities Can Do

Drinking water systems must be designed, constructed, and operated in a manner protective of public health. The information below covers the following four categories of projects related to design and construction of public drinking water systems:

All Projects

  • Local governments have authority to help protect drinking water beyond requirements of state and federal laws and regulations. Determine what is best for the health and welfare of your community.
  • Plan ahead by developing and using a comprehensive land use management plan that includes the impacts of present and future water management (for example, well construction, current and future water availability for an area, fire protection water) and addresses present and future needs of an area for adequate, safe, and sustainable drinking water. Meet with DEQ to discuss recommendations for plan development and implementation.
  • A county or city may want to understand the type of drinking water system needed for a project prior to project approval. The project will generally fall into one of the following three categories:
    • Projects that use an existing public water system
    • Projects that propose a new public water system
    • Projects that use individual wells
  • DEQ recommends that all projects first consider connecting to an existing approved public drinking water system whenever possible. If not possible, DEQ recommends developing a new public drinking water system rather than using of individual wells.
  • Prior to project approval, the applicant proposing to construct a new public drinking water system or expand an existing system must demonstrate an adequate water source for both quantity and quality.
  • For owners (city, district, or other entity) of an existing drinking water system, the following information applies when constructing new facilities or constructing improvements to existing facilities:
    • Understand the responsibilities. A city, district, or other entity that owns or operates a public water system (PWS) is responsible for protecting the health of its drinking water customers by monitoring the quality and available quantity of drinking water and fulfilling the requirements of Idaho rules.
    • Understand the rules. Different rules apply to different types of PWSs in Idaho. Determine which type of PWS you operate. Under Idaho's Rules for Public Drinking Water Systems, four basic categories of requirements apply to PWSs:
      • Construction and engineering
      • Ongoing monitoring
      • Reporting
      • Operation and maintenance
  • Understand the system by taking these steps:
    • Talk to the operator of the PWS to determine the status of the system.
    • Understand the certification requirements needed by an operator.
    • Consider having a city and county elected official attend on-site inspections. While not required, it is a good idea to participate to understand the requirements and be aware of deficiencies.
    • If correspondence from state or federal agencies such as DEQ or EPA is received, contact the agency directly for questions.
    • Meet with regulating agencies, such as the DEQ regional office, to determine operating responsibilities, accountable parties, and issues affecting the PWS.
    • Consider developing a facility plan for all drinking water systems, regardless of plans for growth. Doing so can help identify deficiencies in a system in advance of new projects so ample time is available to address problems or issues. Public drinking water systems are responsible for continually ensuring adequate capacity.
  • Identify and implement pollution prevention measures.

Projects that Use an Existing Public Drinking Water System

  • DEQ requires verification that adequate water is available to serve projects. Prior to project approval, the city and county may want to contact the water provider for three items:
    • A capacity statement or declining balance report
    • The system's willingness to serve the project
    • The system's ability to serve the project

Note: These items are required by DEQ for project review/approval.

  • If a project proposes modifications to an existing public drinking water system, per Idaho Code §39-118 and Idaho's Rules for Public Drinking Water Systems, all components of public drinking water system construction, including wells, must be designed by an Idaho registered professional engineer (An Idaho licensed professional geologist may design wells.) and must be approved by DEQ prior to construction. In some circumstances, a Qualified Licensed PE (QLPE) other than the design engineer may approve a project in place of DEQ. Refer to Idaho Code §39-118 and Section 504 of the Idaho Rules for Public Drinking Water Systems to determine design review authority.
  • DEQ does not review plans for individual service lines; these should be reviewed by the State Plumbing Bureau and/or the local building department, according to the Memorandum of Understanding with DEQ. Contact DEQ to discuss requirements for other service lines that include mechanical components.
  • All projects require preconstruction approval by DEQ unless they meet the provisions of Idaho Code §39-118.2.d. For existing water systems with adequate capacity and pressure, the plans for simple drinking water main extensions may qualify to be reviewed and approved prior to initiation of construction by a QLPE. These simple water main extensions are the only drinking water projects that require no plan review coordination with DEQ prior to approval. Additionally, at the discretion of any city, county, quasi-municipal corporation, or regulated public utility, these types of projects that fall under Idaho Code §39-118.2.d may be referred to DEQ for approval if desired.

Projects that Propose a New Public Drinking Water System

  • If a project will serve 25 or more people for 60 days per year or more, or if it will have 15 or more service connections, it meets the definition of a public drinking water system and is regulated under the Safe Drinking Water Act and Idaho's Rules for Public Drinking Water Systems.
  • Plan ahead by understanding a water system's plans and the community's needs for growth. Doing so can help identify potential future deficiencies in a system in advance of adding more users that could, for instance, cause a system to qualify as a public water system and/or suffer pressure, flow, and supply limitations.
  • Prior to project approval, request that project information specify which requirements under Idaho Code §39-118 and 39-103(12) and the associated Idaho's Rules for Public Drinking Water Systems apply. Generally, the following considerations apply:
    • DEQ recommends that the developer and engineer schedule a pre-design meeting with DEQ early in the conceptual design stage.
    • Projects that propose a new PWS are required to have a general facility plan that covers the system's conceptual design and a specific engineering report approved by DEQ before plans and specifications are submitted to DEQ for review and approval.
    • A project proposing a new PWS is required to demonstrate technical, financial, and managerial capacity. The capacity demonstration must be submitted to and approved by DEQ prior to or concurrent with proceeding or causing to proceed with construction of a new community or nontransient, noncommunity drinking water system. A transient system (one that does not regularly serve the same 25 people, e.g. a restaurant) does not need to demonstrate technical, financial, and managerial capacity.
    • If a PWS project involves a new well or surface water source, the facility plan/preliminary engineering report must include documentation that the appropriate water right approval has been granted by the Idaho Department of Water Resources.
    • If the PWS will be used to provide water for fire suppression, contact local authorities for fire flow requirements. Any fire flow requirements are in addition to domestic requirements.

Projects that Use Individual Wells

Determine if the project will use a new or existing well.

Individual or private wells that serve fewer than 15 connections or do not serve 25 or more people more than 60 days out of the year are not regulated by the state for water quality.

  • Owners of individual wells are responsible for monitoring the quality of their drinking water. In addition, individual well construction in most cases is not equivalent to public drinking water system well construction. Therefore, DEQ recommends that private wells be tested for total coliform bacteria, nitrate, and nitrite prior to use and retested annually thereafter. Nitrate and arsenic are particularly important because they are the most widespread ground water contaminants in Idaho.
  • If the project is using an existing individual well, prior to approval of a project, verify that the change in population size and type (such as employees, children in daycare, or students) does not change the status of the drinking water system. Contact the local Public Health District with the population type information for verification.
  • If a project will use individual wells, it is advisable to evaluate the potential to meet fire flow requirements.
  • If a project proposes the use of individual wells for each residential domestic water supply, the local Public Health District has oversight of the systems.

Staff Contacts

Drinking Water Protection and Finance Division Administrator
Jerri Henry
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0471

Drinking Water Field Services Coordinator
Curtis Stoehr
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0542

Drinking Water Compliance and Enforcement
Bryan Zibbell
DEQ State Office
Water Quality Division
1410 N. Hilton
Boise, ID 83706
(208) 373-0343

DEQ Resources

Search for an Operator

How to Hire an Engineer for Public Water System and Wastewater System Design or Modification

Related Pages

Drinking Water in Idaho

For Engineers and Developers

Pollution Prevention for Public Water Systems

Public Water System Switchboard

Public Water System Planning Grants

Public Water System Construction Loans

Arsenic in Drinking Water

Nitrate in Ground Water