Water resources in your region


Tap Water

A public water system is defined by the Environmental Protection Agency (EPA) as “a system for the provision to the public of water for human consumption through pipes or other constructed conveyances, if such system has at least fifteen service connections or regularly serves at least twenty-five individuals.” A public water system can be either publicly or privately owned.



Federal: The United States Environmental Protection Agency (EPA) regulates public water systems with the Safe Water Drinking Act (SWDA).

The SDWA gives the EPA the authority to set national health-based standards for drinking water to protect against contaminants that may be found in drinking water. EPA regulations implementing SWDA are found in Title 40 of the Code of Federal Register.

State: Under the SDWA, states that set regulations which are at least as stringent as US EPA’s, may apply for, and receive primary enforcement authority.



Federal: There are two categories of drinking water regulations containing contaminant standards: the National Primary Drinking Water Regulations and the National Secondary Drinking Water Regulations.

The National Primary Drinking Water Regulations
These are limits for contaminants that can adversely affect human health and are known or anticipated to occur in water. Examples include lead and arsenic. The limits, established as Maximum Contaminant Levels (MCLs) or Treatment Techniques (TT), are legally enforceable standards for public water supplies.

National Secondary Drinking Water Regulations
These are limits for contaminants which can adversely affect the aesthetic quality of water (taste, odor, color) or other non-health related undesirable effect. The limits, established as Secondary Maximum Contaminant Levels (SMCLs), are recommended. While the standards are not enforceable at the federal level, some states have chosen to enforce the SMCL standards for public water supplies in their state.

State: States’ regulations do not have to be identical to that of the EPA, however, the state does have to demonstrate differences are at least as protective of public health. States’ drinking water regulations can, therefore, differ from that the EPA. Some differences of state drinking water regulations from that of the EPA may include:

  • More stringent maximum contaminant levels
  • Standards for contaminants not yet regulated by EPA

Testing Frequencies

Federal: The EPA regulations in 40 CFR 141 and 143 include monitoring schedules for public water systems. The frequency with which a particular public water system is required to test under EPA regulations is based upon the following factors: type of system, system size, source type, detections or known risks, and any monitoring waivers or variances which have been granted. The EPA’s Standardized Monitoring Framework, provides guidance to states on creating a monitoring framework which meets EPA criteria.

The Standardized Monitoring Framework shows how the variables of system size, system type, source type, detections and waivers provide a range of monitoring requirement frequencies and schedules. For example, a public water system obtaining water from a groundwater source may qualify for a waiver for some or all of the contaminants classified as VOC’s. This ability to qualify for a waiver is another difference between the rigorous testing standards for bottled water as contrasted with tap water. If a public water system did not receive a waiver, and have completed the initial round of monitoring for four quarters with no detects, the system qualifies to reduce testing to annually. A system can qualify for further reduced testing requiring just one sample for each three year compliance period, if they continue to receive no detections for these contaminants.

EPA regulations provide guidance regarding where samples are to be collected. Most contaminants (radiologicals, inorganic chemicals, organic chemicals, volatile organic chemicals, are required to be sampled at the point where the water enters the distribution system. However, total coliform, and sometimes disinfectants, disinfection by-products, and asbestos are required to be collected from points in the distribution system. Lead and copper samples and a handful of other water quality parameters are required to be collected from cold water taps in homes/buildings that are at high risk of lead or copper contamination. However, there is no set testing requirement for microbiological contaminants at the cold water tap.

State: Monitoring schedules for individual systems are based upon the EPA regulations or the State Drinking Water Regulations as approved by the EPA if the state has been granted primacy.


Compliance & Enforcement

Federal: The EPA Safe Drinking Water Act requires systems who have received a Notice of Violation of the Safe Drinking Water Act that may have “serious adverse effects” to issue public notice within 24 hours of the violation occurring. The notice must include a description of the violation, what actions are being taken to correct the violation, and what actions should be taken by consumers such as not consuming or a boil order. Along with consumers, the State must be notified of the serious effect violation.

The Safe Drinking Water Act also requires every community water system that serves at least 25 residents year round or that has at least 15 service connections to prepare and distribute a consumer confidence report to all municipal customers by the July 1 of each year.

State: States granted primacy by the EPA are required to establish and enforce state regulations to include EPA SDWA requirements for monitoring, reporting, performing treatment techniques, record keeping, and public notice requirements. States keep data for systems they regulate in the state data system and are required to submit reports of violations of Maximum Contaminant Levels and treatment techniques, as well as monitoring violations, to the U.S. EPA.


Protection Guarantees

Both EPA and states can take enforcement actions against any water system that is not meeting safety standards. Enforcement actions may include administrative orders, legal actions or fines.



United States Environmental Protection Agency. Safe Drinking Water Act. 11 Sept 2008 <http://uscode.house.gov/download/pls/42C6A.txt>

United States Environmental Protection Agency. National Primary Drinking Water Regulations: Consumer Confidence Report 1998. Sept 11 2008 < http://www.gpo.gov/fdsys/pkg/FR-1998-08-19/html/98-22056.htm>

United States Environmental Protection Agency. “Stage 1 Disinfectants and Disinfection Byproducts Rule: A Quick Reference Guide.” May 2001. 12 Sept 2008 http://www.epa.gov/safewater

United States Environmental Protection Agency. “Total Coliform Rule: A Quick Guidance.” November 2001. 12 Sept 2008 <http://www.epa.gov/safewater>

United States Environmental Protection Agency. “The Standardized Monitoring Framework: A Quick References Guide.” March 2004. 12 Sept 2008 http://www.epa.gov/safewater

United States Environmental Protection Agency. “Lead and Copper Rule: A Quick Reference Guide.” March 2004. 12 Sept 2008 http://www.epa.gov/safewater

Drinking Water Research Foundation. Bottled Water and Tap Water – Just the Facts. October 2011, revised March 2014 <http://thefactsaboutwater.org/wp-content/uploads/2017/05/BW-PWS-Just-the-Facts-2011-rev-0314-Enc.pdf>

Stephen C. Edberg (2015). Microbial Health Risks of Regulated Drinking Waters in the United States — A Comparative Microbial Safety Assessment of Public Water Supplies and Bottled Water, Topics in Public Health, Dr. David Claborn (Ed.), InTech, DOI: 10.5772/58879. Available from: https://www.intechopen.com/books/topics-in-public-health/microbial-health-risks-of-regulated-drinking-waters-in-the-united-states-a-comparative-microbial-saf