--- title: "U.S. Water Quality by State (2026) - Data & Filtration Hub" description: "State-by-state water-quality hub. EPA, EWG and USGS figures plus the right whole-house filtration for each region." lang: en json-ld: | [ { "@context": "https://schema.org", "@type": "Organization", "name": "Whole House Water Treatment", "url": "https://wholehousewatertreatment.com", "description": "Independent U.S. reviews of whole-house water filters, softeners and reverse osmosis systems, plus state and city water-quality guides." }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://wholehousewatertreatment.com/" }, { "@type": "ListItem", "position": 2, "name": "Water quality", "item": "https://wholehousewatertreatment.com/water-quality" } ] } ] --- [![Whole House Water Treatment logo](/assets/logo-Cd_iTZFZ.png)Whole House Water Treatment WHWT ](/) [Find Your System](/find-your-system)[Best Filters](/best-whole-house-water-filters)[Best Softeners](/best-water-softeners)[Well Water](/best-well-water-filtration-systems)[Water Quality](/water-quality)[Guides](/buying-guides)[Learn](/learn)[About](/about) 1. [Home](/) 2. Water quality # U.S. water quality by state ![Clear water flowing from a polished chrome kitchen faucet into a glass](/assets/hero-water-quality-COGzm6w_.jpg) State hubs collect the headline water-quality figures for major utilities, link out to city-level guides, and suggest the type of whole-house treatment that fits the local water profile. U.S. water quality is not uniform. The Mountain West and Southwest run hard and high in chromium-6 and arsenic from the underlying geology. The Gulf Coast and Florida deal with sulfur, color, and disinfection byproducts. The Great Lakes region is comparatively soft but still flags lead service lines in older housing stock. The Northeast and Mid-Atlantic have aging infrastructure and growing PFAS detections. Every utility on these pages meets the federal EPA legal limits. The flagged contaminants are values sitting above EWG's stricter, non-enforceable health guideline, which is the benchmark most home-treatment decisions are made against. Start with your state, then drill down to your city. If your city is not yet listed, the nearest metro inside the same state is usually a reasonable proxy because regional source water and treatment plants tend to be shared. How to read the numbers on this page Every U.S. utility we cover meets the federal EPA legal limits for drinking water. Figures flagged as _"above the health guideline"_ refer to the stricter, non-enforceable benchmark published by the Environmental Working Group (EWG), **not** a legal violation. We share these figures so households can decide whether they want extra filtration - they are not a statement that the water is unsafe or illegal to drink. Always check your utility's annual Consumer Confidence Report (CCR) and the [EWG Tap Water Database](https://www.ewg.org/tapwater/) for the most current data on your zip code. - [AZ Arizona An estimated 6M+ residents affected by contamination. Up to 670 utilities reported elevated nitrate, arsenic and chromium-6. ](/water-quality/az) - [CA California Mixed surface and groundwater across regions; chromium-6, nitrate and arsenic are recurring concerns, particularly in Central Valley agricultural areas. ](/water-quality/ca) - [FL Florida Hard water and disinfection byproducts are widespread; aquifer-fed utilities commonly test for elevated hardness and TTHM. ](/water-quality/fl) - [IL Illinois Lake Michigan supplies most of northern Illinois with soft–moderate water; lead service lines remain a concern in older Chicago-area homes. ](/water-quality/il) - [IN Indiana Limestone aquifers produce some of the hardest water in the Midwest; many utilities serve water at 12+ gpg. ](/water-quality/in) - [MN Minnesota Surface and groundwater are typically very hard; Mississippi-fed utilities also test for nitrate. ](/water-quality/mn) - [MO Missouri Mixed surface and limestone-aquifer sources; hardness is the main issue for most households. ](/water-quality/mo) - [NE Nebraska Agricultural runoff drives nitrate concerns in many Nebraska utilities; some surface systems also see elevated TTHM. ](/water-quality/ne) - [NV Nevada Most population served by Colorado River water via Lake Mead. Arsenic and chromium-6 are recurring concerns in groundwater-served communities. ](/water-quality/nv) - [NY New York Catskill / Delaware surface water serves NYC; older buildings statewide still have legacy lead service lines. ](/water-quality/ny) - [PA Pennsylvania Ranks among the most contaminated states. About 19% of tested systems had PFAS above the EPA standard; USGS found PFAS in 76% of sampled PA rivers and streams. ](/water-quality/pa) - [TX Texas Up to 207 contaminants detected statewide. Over 700 water systems reported TTHM above the EPA legal limit of 80 ppb, reaching an estimated 8.6M people. ](/water-quality/tx) - [UT Utah Mountain snowmelt and groundwater produce hard water in most Wasatch Front communities. ](/water-quality/ut) Whole House Water Treatment Independent, U.S.-focused reviews and water-quality guides for whole-house filters, softeners and reverse osmosis systems. Informational only - not medical or safety advice. 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