Water Quality Testing: Key Insights for Municipalities


Maintaining Public Health & Transparency

Municipal and local government leaders have a great responsibility to help provide clean, safe water for residents. They must work collaboratively with utility managers and other professionals in order to make sound decisions regarding the treatment of public drinking water supplies. Regular water quality testing provides important data to help inform these decisions.

The Safe Drinking Water Act (SDWA) requires community water systems to meet federal regulations set by the U.S. Environmental Protection Agency (EPA). Currently, systems must meet regulations for the presence and levels of over 90 contaminants in public drinking water, including microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals, and radionuclides. The EPA manages and updates these regulations periodically to reflect the levels that protect human health and are attainable using the best available technology. For example, recent scientific advancements have brought PFAS drinking water contaminants to the attention of the EPA, and national maximum contaminant levels (MCLs) are expected to be finalized by early 2024 as a result. In addition to the EPA drinking water standards, many states have also enacted their own regulations. In order to maintain compliance, drinking water systems must ensure that the contaminant levels detected do not exceed the MCLs allowed for each substance. This requires careful adherence to required testing schedules and methods.

This blog will explain the importance of water quality testing and its role in maintaining healthy communities and public trust. We will also describe the water testing process and provide insight on potential upcoming changes to water quality testing requirements for emerging contaminants.

Sources of Water Contamination

Even though U.S. tap water supplies are considered among the safest in the world, water contamination can still occur. There are many possible sources of contamination, including but not limited to:

  • Sewage releases
  • Naturally occurring chemicals and minerals such as arsenic, radon, and uranium
  • Local land use practices (for example, fertilizers, pesticides, or livestock)
  • Manufacturing processes utilizing heavy metals or cyanide
  • Malfunctioning on-site wastewater treatment systems or septic systems

When contaminants are released into the environment, they may leach into the soil and surrounding water sources. This can result in surface water contamination, groundwater contamination, or compromised drinking water wells. Water systems and local governments are required to carefully follow all water quality testing guidelines and regulations to ensure that any contaminants are detected in a timely manner before they result in a public health emergency.

Water Quality Testing Process

Water quality testing procedures can be complex and often vary depending on the contaminant being tested. In general, the process involves a series of steps designed to monitor and analyze various physical, chemical, and biological parameters of the water to identify any potential contaminants that might compromise public health and safety. Water utility personnel must follow a systematic procedure to collect samples, transport them safely to an approved laboratory, and interpret and publish results. Sampling frequency and locations are determined based on regulations, guidelines, and the specific needs of the municipality. Critical points within the distribution system are often prioritized for testing, including those closer to potential contamination sources.

The typical steps of the water testing process are as follows:


The process begins with collecting water samples from different points within the municipal water distribution system. These points may include sources like reservoirs, treatment plants, pumping stations, storage tanks, and distribution networks. The samples are collected in sterilized containers following strict protocols to prevent any contamination during the collection process.

Transport and Preservation:

Collected samples are transported to the laboratory for analysis following proper preservation techniques to maintain the integrity of the samples. This might involve chilling, adding preservatives, or avoiding exposure to light, depending on the parameters being tested.

Laboratory Analysis:

  • Physical and Chemical Analysis: Physical analysis includes visual inspections for color, clarity, and odor. Turbidity (cloudiness) is measured using a turbidimeter, and temperature is also recorded. Various chemical constituents are tested to ensure compliance with regulations and guidelines. Common parameters include pH (acidity/alkalinity), dissolved oxygen, total dissolved solids (TDS), hardness, alkalinity, chlorides, nitrates, and heavy metals such as lead, copper, and arsenic. Specialized instruments and techniques are used to measure the various physical and chemical parameters. Spectrophotometers, ion-selective electrodes, and titration methods are common tools for chemical analysis.

  • Microbiological Analysis: Microbiological testing involves culturing bacteria in a controlled environment to detect their presence. This may take time as cultures need to grow. Alternatively, rapid tests like polymerase chain reaction (PCR) can be used to identify genetic material from microorganisms. These tests detect the presence of harmful microorganisms like bacteria, viruses, and protozoa. Coliform bacteria are often used as indicators of potential fecal contamination. Other pathogens such as E. coli and Cryptosporidium might also be tested for.

  • Disinfection Byproduct Analysis: Chlorine and other disinfectants used in water treatment can react with organic matter to form disinfection byproducts. Testing for these compounds is important to ensure they are within acceptable limits.

Data Interpretation:

The results from the laboratory are compared against drinking water standards set by relevant regulatory agencies such as the Environmental Protection Agency (EPA) or state agencies. These standards dictate the permissible levels of contaminants in drinking water.

Reporting and Action:

If any parameters exceed the acceptable limits, the municipality takes appropriate actions. These actions could include adjusting treatment processes, implementing corrective measures, issuing advisories or boil-water notices, and informing regulatory agencies and the public about the situation.

Continuous Monitoring:

Regular monitoring and testing are essential to ensure the consistent quality and safety of municipal drinking water. The data collected over time helps identify trends and potential long-term issues.

Public Transparency:

Municipalities are required to publish water quality reports, often called Consumer Confidence Reports, which provide residents with information about the quality of their drinking water. These reports typically include test results, information about the water source, treatment processes, and any detected contaminants.

Testing for some contaminants requires additional steps and precautions to ensure accuracy. For example, PFAS testing requires specialized equipment and procedures to minimize the risk of contamination during sampling. PFAS may be present in personal care products used by water testing personnel as well as tools and containers typically used to collect samples. To minimize the risk of error, the EPA created an instruction video to help water systems comply with PFAS water testing requirements.

Water Testing Requirements: A Moving Target

Since the Safe Drinking Water Act was passed by Congress in 1974, there have been significant advances in scientific knowledge of water contaminants, as well as the technology available to detect and remove them from water sources. As such, water quality regulations are updated on a consistent basis through a series of processes managed by the EPA. At times, the EPA adjusts existing MCLs for regulated contaminants because more advanced water testing and treatment technologies become widely available, making it feasible for public water systems to meet stricter standards.

When previously unregulated contaminants are suspected of presenting unreasonable danger to public health, the EPA can also enact new regulations through a process directed by the Unregulated Contaminant Monitoring Rule, or UCMR. The UCMR process requires water systems across the country to test for a list of 30 emerging contaminants of concern every five years, providing essential data to inform future regulatory decisions and ensure that U.S. drinking water supplies remain safe for the public.

UCMR5 PFAS Testing

Currently, public drinking water systems across the country are in the process of testing their water sources for 29 different per- and polyfluoroalkyl substances (PFAS) and lithium as required by the Fifth Unregulated Contaminant Monitoring Rule, or UCMR5. Systems that are subject to the rule must conduct periodic testing according to their type of water source. Surface water, ground water under the direct influence of surface water, or mixed sources systems must monitor 4 times during a consecutive 12-month monitoring period, and sample events must occur 3 months apart. Groundwater systems must monitor 2 times during a consecutive 12-month monitoring period, and sample events must occur 5-7 months apart.

The results of this testing will be made public as they become available. As of August 2023, the EPA has released the first set of data on the presence and levels of these contaminants in water systems. The data, which represent only about 7% of the results expected from all required testing under UCMR5, reveal the presence of at least one PFAS compound in hundreds of community water systems, serving more than 27 million Americans.

The EPA announced the proposed MCLs for several PFAS compounds in March 2023, and they are expected to be finalized by early 2024. Furthermore, public concern over the dangers of PFAS is at an all-time high as contamination concerns continue to make headlines. Considering both the impending regulatory obligations and public trust concerns surrounding PFAS concentrations, water systems should carefully assess their PFAS situations and explore treatment and cost recovery options before issues get out of hand.

Planning Ahead for 1,4-Dioxane Testing

1,4-dioxane is a dangerous chemical that has been discovered as a contaminant in many groundwater and drinking water sources. Research has shown associations between exposure to the chemical through drinking water and increased risks of cancer and adverse organ function effects. Some states have already responded, either by enacting their own maximum contaminant level (MCL) for the chemical or by beginning the process to set an MCL. While 1,4-dioxane has not yet been made subject to enforceable federal drinking water regulations, in July 2023, the EPA released an updated risk evaluation for 1,4-dioxane, determining that the chemical presents an unreasonable risk of injury to human health. This announcement served as an indication that the EPA is continuing on the path towards establishing standards for 1,4-dioxane in drinking water.

The EPA’s next steps may include the development of a roadmap towards federal regulations to protect the environment and public health from the dangerous effects of exposure to this chemical. If standards are created, water systems that have already begun testing and analysis of the 1,4-dioxane concentrations within their water supplies may benefit from taking early action. By evaluating their 1,4-dioxane challenges before regulations take effect, they may even have more time to explore cost recovery solutions that could prevent ratepayers and municipalities from bearing the expense of new or upgraded water treatment facilities.

Take Action to Maintain Water Quality

Leaders and decision-makers within local governments, utilities, and water systems have a duty to provide safe, healthy drinking water to residents and ratepayers. Regular water quality testing can help detect potential contaminants and threats to water quality before they get out of hand. If contaminants have been detected in your system’s water supply, you should begin researching available treatment options and/or alternative water sources immediately. The earlier your water system begins planning its water quality solutions, the more time you will have to evaluate potential cost recovery options to protect your system and ratepayers from the costs of treatment, which can often be millions of dollars or more.

Fortunately, there are several different funding options available to help water systems cover the cost of removing contaminants. Government grants and public infrastructure funding are a great start, but they may not provide enough to cover the full cost of acquiring alternative water sources, building or updating treatment facilities, and operating them for years to come. One other funding option that has been gaining momentum recently is the use of the legal process to recover water treatment costs from the companies responsible for pollution. Many water systems throughout the country have already found success with this method. For example, over the past 20+ years, SL Environmental Law Group has helped hundreds of states, municipalities and water providers successfully recover costs for a variety of contaminants, such as 1,2,3-TCP, perchlorate, MTBE, p-CBSA, PCE and PCBs. The firm also currently represents over 100 clients - including states, municipalities, water suppliers, and airports - in the ongoing PFAS multidistrict litigation (MDL).

If your water system is dealing with contamination issues, or if you are concerned about your system’s water testing results, schedule a free consultation with the team at SL Environmental Law Group to learn more about your options.