Best Tap Water in the US by State

Last updated: February 2026

How We Rank States

Water quality varies enormously — not just state to state, but city to city and even neighborhood to neighborhood. Our state rankings aggregate multiple data sources:

• EPA Safe Drinking Water Information System (SDWIS): Health-based violations and monitoring compliance rates for all public water systems
• EWG Tap Water Database: Contaminant levels compared against health guidelines (not just legal limits)
• USGS Water Quality Monitoring: Source water quality data for rivers, lakes, and aquifers
• American Society of Civil Engineers Infrastructure Report: Age and condition of water infrastructure
• State-level health data: Compliance rates and enforcement actions

Top 10 States for Tap Water Quality

These states consistently demonstrate high EPA compliance rates, lower contamination levels relative to health guidelines, and better-maintained water infrastructure:

Why Hawaii Ranks #1

Hawaii's water quality advantage is largely geological. The islands' volcanic basalt acts as a natural filter for rainwater as it percolates into deep aquifers. These isolated groundwater sources are protected from many continental contaminants — no agricultural runoff from Iowa, no legacy industrial pollution from the Rust Belt.

That said, Hawaii has faced documented PFAS contamination near military installations, particularly in Oahu where the Red Hill fuel leak contaminated drinking water for thousands of military families in 2021–2022. This serves as a reminder that even the best natural water systems can be compromised by human activity.

Why New York Ranks #9 Despite the NYC Hype

New York City's water is genuinely excellent — a watershed management program in the Catskill Mountains is internationally recognized as a model for source water protection. NYC is one of only five large cities in the U.S. exempt from required filtration due to the quality of its source water.

But New York State contains thousands of smaller water systems outside the city, many with aging infrastructure, lead service lines, and documented PFAS contamination (particularly near Hoosick Falls and other upstate communities). The state average brings the ranking down from where the city alone would place. Read our full New York water quality guide →

States With the Most Water Quality Challenges

These states face systemic water quality challenges — whether from agricultural contamination, aging infrastructure, industrial legacy pollution, or inadequate regulatory enforcement:

The Jackson, Mississippi Case Study

Jackson's water crisis became national news in 2022 when the city of 150,000 people lost water pressure for weeks after flooding overwhelmed a crumbling treatment plant. The system had documented violations going back years. Residents went months without safe drinking water. The crisis was the culmination of decades of infrastructure neglect, inadequate funding, and regulatory failures.

Jackson's story isn't unique — it's an extreme version of what many mid-sized American cities with aging infrastructure face. The American Society of Civil Engineers gives the U.S. drinking water infrastructure a grade of C–, with an estimated $1 trillion funding gap needed over the next 25 years.

All 50 States at a Glance

Below is a summary of primary water quality concerns for each state. Remember: these are generalizations. Your specific utility may perform significantly better or worse than the state average.

Best Cities for Tap Water

These cities are consistently praised for tap water quality — a combination of clean source water, modern infrastructure, and rigorous treatment:

• New York City, NY: The Catskill-Delaware watershed system is one of the largest unfiltered water supplies in the world. NYC water has won multiple national taste tests and is a model for source water protection.
• Des Moines, IA: Despite Iowa's agricultural challenges, Des Moines Waterworks has invested heavily in advanced treatment — including a landmark nitrate removal facility.
• Boulder, CO: Rocky Mountain source water, excellent infrastructure, and a commitment to transparency. Boulder regularly tests well above EPA requirements.
• Louisville, KY: Louisville Water Company has won "Best Tasting Water" awards at national competitions and maintains rigorous quality monitoring.
• Memphis, TN: Draws from a deep, naturally filtered aquifer (the Memphis Sand Aquifer) that provides some of the cleanest groundwater in the country.
• Silverdale, WA: Small-town Washington state draws from pristine Cascade mountain sources with minimal treatment needed.

Worst Cities for Tap Water

Several major cities have documented water quality challenges that require ongoing attention:

• Flint, MI: The Flint water crisis (2014–2019) exposed 100,000 people to lead. Infrastructure improvements are ongoing, but trust remains low.
• Pittsburgh, PA: Lead levels exceeded federal action levels in 2016. The city has replaced thousands of lead service lines but work continues.
• Newark, NJ: Lead contamination crisis in 2019 led to a massive filter distribution program. Infrastructure upgrades are ongoing.
• Jackson, MS: Water system failures in 2022 left residents without safe water for extended periods. Ongoing infrastructure crisis.
• Willowbrook, IL: Made national news for chromium-6 contamination from a former Sterigenics facility.
• Hoosick Falls, NY: One of the first U.S. communities to identify PFAS contamination in drinking water, leading to national awareness.

Regional Contamination Patterns

Water quality concerns aren't random — they follow geographic and economic patterns:

Midwest / Corn Belt: Nitrates & Pesticides

States like Iowa, Illinois, Indiana, and Nebraska face pervasive agricultural runoff. Nitrates from fertilizers and pesticides like atrazine contaminate both surface water and groundwater. Des Moines Water Works famously sued Iowa drainage districts over nitrate levels in the Des Moines and Raccoon Rivers — the lawsuit was dismissed, but highlighted the collision between agriculture and clean water.

Industrial Rust Belt: Lead & PFAS

Pennsylvania, Michigan, Ohio, and New York (upstate) carry the legacy of heavy manufacturing. Lead service lines installed in the early 20th century still serve millions of homes. PFAS contamination from industrial use and firefighting foam (AFFF) at airports and military bases is widespread.

Southeast: Disinfection Byproducts & Agricultural Chemicals

Warm temperatures and high organic matter in source water (rivers, swamps, wetlands) create conditions for elevated disinfection byproducts. Florida, Louisiana, and Mississippi struggle with DBPs alongside agricultural chemical runoff from sugar cane, cotton, and poultry operations.

Southwest: Arsenic, Uranium & Water Scarcity

Natural geology in Arizona, New Mexico, Nevada, and Utah concentrates arsenic and uranium in groundwater. Compounding this is the water scarcity crisis — as the Colorado River shrinks and aquifers are overdrawn, communities face pressure to use lower-quality water sources with less dilution.

Pacific Northwest: Generally Clean, with PFAS Concerns

Oregon and Washington benefit from relatively pristine Pacific sources, but PFAS contamination from military bases and some industrial sites has been detected. Wildfire events have raised concerns about ash contamination of source water in recent years.

How to Check Your Specific Water

State rankings are useful context but they don't tell you about your specific tap. Here's how to check your actual water quality:

Frequently Asked Questions