A drinking water system provides water for human consumption through pipes or other constructed conveyances. A drinking water system is a Public Water System (PWS) if it has at least 15 service connections or regularly serves an average of 25 or more people for at least 60 days per year.
A PWS can be one of three types:
- Community Water System – Serves at least 15 service connections or 25 people year-round in their primary residences (e.g., cities, towns, apartment complexes, and mobile home parks with their own water supplies).
- Nontransient Non-community Water System (NTNCWS) – Serves at least 25 of the same people over 6 months per year (e.g., schools, churches, factories, and hospitals that have their own water supplies).
- Transient Non-community Water System (TNCWS) – Serves an average of at least 25 people, but not necessarily the same people, over 6 months per year (e.g., campgrounds, rest stops, and gas stations that have their own water supplies).
Additionally, a PWS may be a consecutive system if it receives some or all of its finished water from one or more wholesale systems. Delivery from a wholesale system to a consecutive connection may be through direct connection or through the distribution system of one or more consecutive systems.
Where Does Drinking Water Come From?
Approximately 95% of the state’s drinking water comes from ground water sources. The remaining 5% is supplied through surface water sources.
Safe drinking water is critical to individual and public health, understanding the quality of your drinking water and what actions to take if it is unsafe are important.
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Each year, community water systems in Idaho are required to prepare annual Consumer Confidence Reports for customers. These reports provide consumers with information on where their drinking water comes from and what is in it. Contact your water supplier for information on the latest report.
DEQ posts water quality data for all public water systems on the Drinking Water Watch application. This application will provide a summary of sample results and overall water quality provided by each system.
Public water systems are required to notify consumers if contaminant levels exceed Idaho’s drinking water regulations, if a waterborne disease outbreak or any other situation occurs that may pose a risk to public health, or the water system fails to test its water as required.
For serious issues, notification is required within 24 hours. For less serious issues, notification is required within 3 to 12 months (depending on the violation). Notifications will describe any precautions a consumer needs to take.
Boil water advisories may be issued by the owner or operator of a public water system or by DEQ. The advisory notifies water system users that the water may be contaminated with potentially harmful bacteria and to boil the water prior to use until further notice. The advisory will provide the reason for its issuance and describe the corrective actions being taken by the water system.
Small quantities of water can be disinfected through:
- Boiling: Boil water for 1 minute. To improve taste of boiled water pour it back and forth from one container to another multiple times, allow it to stand for a few hours, or add a small pinch of salt for each quart of water boiled.
Boiling should not be used if water contains elevated levels of nitrate, heavy metals, or other chemical contaminants. Boiling water with elevated level of contaminants will increase the contaminant concentration. If you have an elevated contaminant level, chemical disinfection should be utilized in lieu of boiling or an alternate source of water such as bottled water should be used.
- Chemical Disinfection: If boiling is not practical, chemical disinfection should be used. The two chemicals commonly used are chlorine and iodine. EPA’s Emergency Disinfection Procedures describe the appropriate products and processes for chemical disinfection.
Lead is rarely in drinking water when it leaves the source or treatment plant. Lead is typically introduced to drinking water by leaching into the water from some service lines and plumbing in buildings and homes. This is most prevalent in older structures that still have lead pipes or piping with lead solder. More information on lead in drinking water can be found on EPA’s website.
Community and non-transient non-community public water systems test their water for lead. Contact your water supplier to discuss sampling efforts and results for your system or building.
Bottled water is not necessarily safer than your tap water but is valuable in emergency situations. EPA sets standards for tap water provided by public water systems. The Food and Drug Administration sets bottled water standards based on EPA’s tap water standards. Bottled water and tap water are both safe to drink if they meet these standards. Consumers should carefully read the label to understand what they are buying with a focus on water source and treatment methods.
Most homes served by a public water system do not require additional treatment. If you have a private well, spring, or surface water intake, it is your responsibility to test your drinking water to ensure that it is safe. Consumers who choose to purchase a home water treatment unit should research several options to ensure your treatment needs will be met. No single treatment unit will remove every kind of drinking water contaminant. If purchased, follow the manufacturer-recommended operation and maintenance procedures and frequencies to ensure performance. DEQ recommends that any drinking water treatment unit meets American National Standards Institute/National Science Foundation (ANSI/NSF) standards. NSF provides a webpage to narrow your search based on contaminants of interest.