Assessing US Water Quality by State (Best to Worst)

US Water Quality Statistics

As the Earth becomes more industrialized, ensuring the purity of our drinking water becomes an ever-pressing issue. The quality of water consumed directly impacts human health and well-being. And it’s not just about hydration; what we drink must be clean, free from contaminants and pollutants like heavy metals and pesticides. So we wondered, how does each U.S. state fare when it comes to providing safe drinking water?

Drawing on data from the U.S. Environmental Protection Agency (EPA), this report provides insights into water quality across the country. The data concerning drinking water violations was sourced from the EPA’s ECHO report, while information on PFAS comes from their Unregulated Contaminant Monitoring Rule. We’ll highlight the best and worst locations through detailed maps and analyses, providing a clear picture of where water quality stands nationwide in 2023.

Water Sources in the United States

Water is the lifeblood of any nation, and in our vast and diverse country, the array of watersheds, wetlands, and other bodies of water plays a pivotal role in shaping our landscape, economy, and way of life. These aquatic ecosystems, from the smallest wetland to the largest body of water, are integral to our environment. This section offers an overview of the primary water sources, including their significance and their role in providing Americans with water.

Types of Water Sources

Groundwater: Beneath our feet, vast reservoirs of water, known as aquifers, provide a significant portion of the drinking water for the U.S. population. Wells are tapped into these aquifers and are a primary water source for many communities, especially in regions where surface water is scarce.

Surface Water: This source includes rivers, lakes, and reservoirs. These water bodies not only offer drinking water but also support agriculture, industry, and recreation. They shape the landscapes and ecosystems of entire regions.

Desalination: In areas with limited freshwater, technologies that convert seawater to drinkable water are gaining traction. Desalination plants are essential for supplementing water supplies, typically in coastal regions.

Water Challenges in the U.S.

While the U.S. has abundant water sources, challenges like pollution, over-extraction, and the impacts of climate change threaten their sustainability. Ensuring clean and sufficient water for future generations requires proactive conservation, sustainable practices, and continuous monitoring.

Water Pollution by State

Water pollution remains a significant concern across the U.S., with various states grappling with diverse challenges. To grasp the extent of this pressing issue, we’ve sourced data from the EPA through their Enforcement and Compliance History Online (ECHO) report. This data provides a comprehensive view of pollutant loadings across different states, categorized under two primary designations: major and non-major facilities.

Understanding Majors and Non-Majors

Knowing the difference between major and non-major facilities is key to comprehending the scale of pollution present. Major facilities are classified based on several criteria, including:

  • Toxic pollutant potential
  • Discharge flow/stream flow volume ratio
  • Conventional pollutant loading
  • Public health impact
  • Water quality factors
  • Proximity to coastal waters

Major facilities have a more pronounced potential to impact water quality adversely. On the other hand, if a facility doesn’t fall under the “major” designation in the ECHO database, it’s automatically considered non-major.

Major Facilities

Facilities with major designations are often more significant sources of pollutant discharges into groundwater and various bodies of water. Common water pollutants include chemicals, heavy metals, sewage, and agricultural runoff. Water pollution can harm aquatic life, contaminate drinking water sources, and degrade ecosystems.

Our maps showcase the total calculated pollutant loadings, in pounds per year, for individual NPDES permits with major designations. Here, you’ll notice a range of states that are top contributors to polluted water and some that have managed to curtail contaminated discharges effectively.

The following states have recorded the highest pollutant discharges. If left unchecked, these discharges can profoundly affect water quality and ecosystems.

States With the Highest Pollutant Pounds per Year for Majors

  1. Texas
  2. Louisiana
  3. Ohio
  4. California
  5. Indiana
  6. Alabama
  7. Oklahoma
  8. Pennsylvania
  9. Minnesota
  10. Missouri

Fortunately, not all major water areas have extreme amounts of pollution. Here are the states with the least amount of pollutant pounds per year.

States With the Lowest Pollutant Pounds per Year for Majors

  1. Washington
  2. Vermont
  3. Delaware
  4. Rhode Island
  5. Wyoming
  6. South Dakota
  7. Connecticut
  8. Hawaii
  9. Maryland
  10. Mississippi

Non-Major Facilities

While non-major facilities might seem less impactful at first glance, their collective contributions to pollutant loadings can’t be underestimated. Our data on non-majors offers insights into the cumulative pollutant loadings from these facilities.

These states had the most pollution in their smaller water sources.

States With the Highest Pollutant Pounds per Year for Non-Majors

  1. Alabama
  2. Nevada
  3. West Virginia
  4. Missouri
  5. North Carolina
  6. Pennsylvania
  7. Nebraska
  8. Ohio
  9. South Carolina
  10. Louisiana

On the brighter side, several states have effectively managed and reduced pollutant discharges, setting examples for best practices in water management.

States With the Lowest Pollutant Pounds per Year for Non-Majors

  1. Delaware
  2. New Hampshire
  3. Hawaii
  4. Washington
  5. Vermont
  6. Maine
  7. Alaska
  8. Massachusetts
  9. New Mexico
  10. North Dakota

While some states have managed to maintain relatively low pollutant discharges, others face significant challenges in mitigating them. It’s essential for communities, policymakers, and industries in high-pollutant states to prioritize water quality improvement initiatives.

Sources of Water Pollution

Water resources can become contaminated with a myriad of toxic substances due to many factors. Human activities, like discharging wastewater (effluent) without the right sewage treatment, are a leading cause of water pollution. Often, wastewater treatment or septic systems don’t remove all contaminants, allowing nitrates, phosphates, and other harmful chemicals to end up in our waterways.

Meanwhile, the excessive use of fertilizers and herbicides in agriculture contributes to algal blooms, while stormwater runoff carries sediment, microplastics, and other pollutants into our aquatic ecosystems. These can subsequently enter the food chain, worsening the issue of plastic pollution.

Industrial waste, which usually contains toxic chemicals, further reduces our water quality. Oil spills from tankers are another big issue, and so are air pollution emissions, which also pollute water sources. Nonpoint source pollution — runoff from urban areas carrying herbicides, phosphorus, and other contaminants — also contributes to it. These all represent severe environmental challenges.

Effects of Water Pollution

Drinking contaminated water, which can contain harmful pathogens, microorganisms, and other unwanted substances, can create health problems and waterborne diseases in our communities. A primary consequence of nutrient-rich pollutants, eutrophication causes algae to grow abundantly, depleting the water’s oxygen and harms aquatic life. These are just some of the main reasons why we need extensive clean-up efforts to ensure water quality and safety.

Safe Drinking Water Act

The Safe Drinking Water Act (SDWA) is a landmark legislation that seeks to ensure the quality of Americans’ drinking water. The EPA established the SDWA to protect public health, regulating the nation’s public drinking water supply and sources.

  • Protection Scope: The SDWA covers all public water systems in the U.S., ensuring that they meet the minimum federal health standards. It doesn’t regulate private wells serving fewer than 25 individuals.
  • Setting Standards: Under the SDWA, the EPA sets health-based standards, known as Maximum Contaminant Levels (MCLs), for contaminants in drinking water. These MCLs strive to strike a balance: they aim to be protective of human health while also considering the cost of treatment borne by water treatment facilities. These standards undergo periodic reviews and can be updated based on the latest scientific findings. It’s worth noting that organizations like the Environmental Working Group (EWG) advocate for even stricter standards that prioritize human health above all else.
  • Monitoring and Compliance: Water providers are required to monitor their supplies regularly for contaminants. If they fail to meet the standards, they must notify the public and take corrective actions.
  • Public Right to Know: One of the core principles of the SDWA is transparency. Water suppliers must annually provide consumers with a Consumer Confidence Report that offers information about the source of their water, the contaminants found in it, and the potential health effects.

While the SDWA is pivotal in ensuring drinking water quality, the Clean Water Act (CWA) offers a broader perspective on the health of U.S. waters, addressing not only sources designated for drinking but also those impacted by various pollutants. The CWA’s mandate to monitor and maintain the nation’s waterways is crucial, as it underscores the collective responsibility to safeguard our natural resources.

The recent findings from the 2022 CWA report shed light on the current state of these waterways:

U.S. Waters Designated as Impaired for Drinking Water Use

  • Rivers and Streams 29%
  • Lakes and Reservoirs 12%

U.S. Waters Classified as “Impaired” Because of Pollution Levels

  • Rivers, Streams, and Creeks 51%
  • Lakes, Ponds, and Reservoires 55%
  • Bays, Estuaries, and Harbors 26%

These statistics highlight the urgency and challenges various regions face in maintaining water quality. They also provide a framework for understanding the measures individual states take to address these issues.

States With the Best Tap Water in the US

Water quality standards can ensure the safety and well-being of the population. Yet, as our analysis reveals, not all states meet these standards with equal rigor.

When we discuss violations, we’re referring to instances where water facilities don’t comply with established health-based standards. Their noncompliance could be due to various factors, ranging from outdated infrastructure to poor management or unforeseen contamination issues.

Our map illustrates the percentage of water facilities in each state with current violations. This metric provides an essential perspective on the widespread water quality issues within each state.

While most states strive to provide clean water to their residents, a few face significant challenges in this domain. The following states had more facilities with reported violations than other states.

States With the Highest Percentage of Facilities With Current Violations

  1. Washington (25%)
  2. Alaska (24%)
  3. West Virginia (17%)
  4. Pennsylvania (13%)
  5. Idaho (13%)
  6. Missouri (12%)
  7. Maine (12%)
  8. New Jersey (11%)
  9. Arkansas (11%)
  10. Ohio (10%)

On a brighter note, several states adhered exceptionally to water quality standards. The following had the lowest percentage of facilities with reported violations, so they are the states with the safest tap water.

States With the Lowest Percentage of Facilities With Current Violations

  1. California (1%)
  2. Minnesota (1%)
  3. Utah (1%)
  4. Nevada (2%)
  5. Florida (2%)
  6. Massachusetts (3%)
  7. Rhode Island (3%)
  8. Oklahoma (3%)
  9. Kansas (3%)
  10. South Dakota (3%)

These statistics present a varied landscape of water quality management across different states. While some states appeared to have significant challenges in ensuring compliance with safe drinking water standards, others have managed to maintain a relatively low violation rate.

States With the Worst Tap Water in the US

The EPA also tracks severe safe drinking water violations, which are instances when noncompliance with water quality standards can seriously affect public health. These situations could be due to the presence of harmful drinking water contaminants in higher quantities or repeated violations over time.

The following map outlines the percentage of water facilities in each state with severe violations, offering a more specific view into the areas where water quality issues might be of greater concern.

A higher rate of severe violations is a clear indication that more stringent measures and immediate action are required. The following have shown a consistent pattern of severe violations, deeming them the states with the worst tap water and necessitating a deeper look into their water quality management.

States With the Highest Percentage of Facilities With Severe Violations

  1. Washington (12%)
  2. West Virginia (6%)
  3. Alaska (5%)
  4. Louisiana (5%)
  5. Pennsylvania (4%)
  6. Kentucky (4%)
  7. North Dakota (4%)
  8. Missouri (3%)
  9. Maryland (3%)
  10. Mississippi (3%)

Conversely, some states managed to uphold stringent water quality standards, reflecting strong governance, modern infrastructure, and proactive measures. These states have consistently reported the lowest instances of severe violations.

States With the Lowest Percentage of Facilities With Severe Violations

  1. California (0.19%)
  2. Utah (0.21%)
  3. Minnesota (0.22%)
  4. Georgia (0.29%)
  5. North Carolina (0.35%)
  6. South Dakota (0.42%)
  7. Florida (0.44%)
  8. Hawaii (0.46%)
  9. Kansas (0.55%)
  10. Tennessee (0.58%)

These insights underline the importance of persistent monitoring, infrastructure upgrades, and public awareness campaigns to ensure all states meet the highest water quality standards.

Understanding PFAS: The “Forever Chemicals”

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been used in a variety of industries around the world since the 1940s. A range of products contain PFAS, from nonstick pans to water-repellent clothing and even some cosmetics. The nickname “forever chemicals” stems from their persistent nature, as PFAS do not easily break down. They can build up in the environment and your body over time.

The potential risks associated with PFAS have gained increasing attention in recent years. Studies have indicated that PFAS exposure can lead to adverse health outcomes in humans, including liver damage, thyroid disease, decreased fertility, and increased risk of certain cancers. Unfortunately, PFAS are found in the blood of nearly all Americans and can contaminate drinking water sources.

Given the potential health risks and their persistence, monitoring PFAS in drinking water has become a priority. The following sections will shed light on the presence of PFAS in different U.S. states, highlighting areas of concern and those that have managed to maintain lower levels of these chemicals.

Traceable PFAS in the Water

PFAS contamination has become a topic of concern for many communities across the U.S. The presence of these chemicals, even in trace amounts, can have implications for public health. Monitoring and identifying such sites is the first step in addressing and mitigating the risks associated with PFAS exposure.

The following states have reported a larger number of sites where PFAS are detectable, indicating potential areas of concern.

States With the Most Sites of Traceable PFAS

  1. New Jersey (75)
  2. Texas (75)
  3. California (67)
  4. Florida (63)
  5. Pennsylvania (50)
  6. North Carolina (40)
  7. Arizona (33)
  8. New York (31)
  9. Ohio (26)
  10. Maryland (25)

On the other hand, the next 10 states reported the fewest sites with traceable PFAS, suggesting either effective mitigation strategies, fewer sources of contamination, or both.

States With the Least Sites of Traceable PFAS

  1. Hawaii (0)
  2. Idaho (0)
  3. Mississippi (0)
  4. North Dakota (0)
  5. Virginia (0)
  6. Wyoming (0)
  7. Missouri (1)
  8. Nebraska (1)
  9. Alaska (2)
  10. Maine (2)

It’s important to note that the presence of traceable contamination doesn’t necessarily indicate a health risk, but it warrants further investigation and potential mitigation measures to remove PFAS from water.

States With Unhealthy Levels of PFAS

While the presence of traceable PFAS warrants attention, sites with high levels of these chemicals present a more immediate concern. The EPA has established that PFAS concentrations exceeding 70 parts per trillion (ppt) are considered unsafe for human consumption. Sites with PFAS levels surpassing this threshold could pose significant health risks to those consuming the water.

The following states reported a higher number of sites where PFAS concentrations exceed the EPA’s safety limits.

States With the Most Sites of Unhealthy Levels of PFAS

  1. Arizona (11)
  2. Florida (10)
  3. Minnesota (5)
  4. New Jersey (5)
  5. California (3)
  6. Delaware (3)
  7. Alabama (2)
  8. Pennsylvania (2)
  9. Colorado (1)
  10. Georgia (1)

It’s critical for states with sites showing unhealthy PFAS levels to take immediate action. This could include conducting further tests, informing the public, and implementing measures to mitigate the contamination.

PFAS and the Safe Drinking Water Act

The increasing awareness of PFAS in drinking water has ignited discussions about the role of the SDWA in regulating these chemicals. While the SDWA provides the framework for establishing health-based standards for contaminants, PFAS represent a complex group of chemicals, and research is ongoing to understand their full impact. The EPA’s mention of the 4 parts per trillion (ppt) threshold for PFAS is an example of how the agency uses the SDWA to provide guidance on emerging contaminants.

Finding Your State’s Water Quality Standards

The Clean Water Act (CWA) is another vital piece of legislation that aims to ensure clean and safe water for all Americans. While the SDWA focuses on drinking water, the CWA deals with the broader spectrum of maintaining the integrity of the nation’s waters, including rivers, lakes, and coastal areas.

Each state, under the guidance of the CWA, establishes its own water quality standards, taking local conditions and needs into consideration. If you want to understand your state’s specific water quality standards under the CWA, the EPA has made this process straightforward.

Start by visiting the EPA’s page dedicated to state-specific water quality standards. Here, you’ll find a comprehensive list of states along with links to their specific water quality standards and regulations. Click on your state to view detailed information about its water quality standards, criteria, and other relevant documentation.

By familiarizing yourself with your state’s standards, you can be more informed about the quality of water in your region and the measures in place to protect it. You can also test water quality in your home to identify problematic contaminants and learn how to address them.

Ensuring Clean Water for All

Water quality is not just a matter of infrastructure or compliance; it’s a reflection of our collective commitment to public health and environmental stewardship. As this report has showcased, there are variations across states in terms of water quality, with some areas facing significant challenges related to contaminants like PFAS. Yet, some states have shown exemplary performance, maintaining high water purity standards.

The presence of contaminants, especially persistent ones like PFAS, underscores the importance of ongoing research, monitoring, and public awareness. Legislation like the SDWA and the CWA provide the framework, but it’s the collective action of policymakers, industry stakeholders, and the public that brings about real change.

For readers, staying informed is the first step. Tools and resources like the EPA’s dedicated page on state-specific water quality standards provide invaluable insights. By understanding water quality in our regions, we can advocate for better practices, support necessary infrastructure upgrades, and make informed decisions about our health and the environment.

In a world grappling with climate change, industrialization, and urbanization, ensuring clean water for all remains both a challenge and a priority. Together, through informed choices and collective action, we can pave the way for a future where clean water isn’t a luxury but a given.

What Can I Do If I Live In a State With Bad Drinking Water Quality?

If you live in a city or state that doesn’t offer access to clean city water, you have a number of options.

First, you could pack your bags and move to another city or state. But that’s an expensive option, and not everyone can simply move cities at the drop of a hat.

A more realistic option is to switch to bottled water. There’s no need to drink the water supplied by your city if it contains chemical contaminants or heavy metals. However, while bottled water has a better taste and quality, it’s more expensive than tap water. You’d have to be prepared to spend a few hundred dollars on bottled water per year – and waste a whole lot of single-use plastic while you were at it.

The most effective and money-saving long-term option is to buy an at-home water filter. Water filters come in a variety of builds and designs, and there are options to suit every budget.

Portable water filters, such as countertop or pitcher filters, are the most affordable. You can also buy under-sink and whole-home filters.

Water filters are designed to remove a number of specific contaminants that are commonly found in tap water provided by cities. Whether your city water is high in chemical impurities, heavy metals, fluoride, or microbiological contaminants, there’s a filter to suit your requirements.

The advantage of filtering your water is that you can access clean water at home, without having to spend money on a large number of plastic water bottles per week. You can control exactly which contaminants are removed from your tap water supply, and you’ll have peace of mind from knowing exactly what you’re drinking.

Related: Which countries have the cleanest water in the world?


About is a leading online resource for in-depth insights, reviews, and guidance on water quality and purification. We educate readers on the best water filtration solutions tailored to individual needs and regions to ensure clean drinking water for all.

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