Lexington, KY Water Quality 2026: Kentucky River Hardness, Chloramine, and PFAS Data

Kentucky American Water serves Lexington and surrounding Fayette County from Kentucky River surface water, treating and distributing to approximately 299,501 residents. The utility uses chloramine disinfection, a common approach for large systems because chloramine produces lower trihalomethane levels than free chlorine at the tap. Water hardness in Lexington averages 120 parts per million, or about 7 grains per gallon, placing it in the moderately hard category by USGS classification. That is substantially softer than the 16 to 22 GPG water in Indianapolis, Fishers, and Fort Wayne, but hard enough to leave noticeable scale on fixtures and reduce appliance efficiency over time. EPA UCMR5 monitoring conducted in 2023 detected five PFAS compounds in Lexington's distribution system, all below the federal maximum contaminant levels that take effect by 2029. This article synthesizes data from the Kentucky American Water Consumer Confidence Report, EPA UCMR5 public records, and USGS source-water assessments. (Sources: Kentucky-American Water CCR; EPA UCMR5 data at epa.gov/dwucmr; waterhardness.org.)

How we compiled this data

This overview draws from four primary public sources. First, the Kentucky American Water Consumer Confidence Report (CCR), published annually under Safe Drinking Water Act section 1414(c)(4) and available at amwater.com/kyaw. Second, EPA UCMR5 monitoring data (2023), the fifth Unregulated Contaminant Monitoring Rule cycle, which required large utilities to test for PFAS and other emerging contaminants, published at epa.gov/dwucmr. Third, the USGS National Water Quality Assessment program hardness classifications for the Kentucky River basin. Fourth, EPA Safe Drinking Water Information System (SDWIS) records at EPA SDWIS (PWSID KY0340250).

Numbers in this article represent typical or reported ranges from those sources. Water quality varies by season and by location within the distribution system. Always verify current-year numbers against your utility's most recent CCR before making treatment decisions. For a broader comparison of PFAS monitoring across Indiana, see our article on Indiana PFAS drinking water under UCMR5.

The Kentucky River: Lexington's water source

The Kentucky River rises in the eastern Kentucky coalfields and flows northwest for roughly 259 miles before joining the Ohio River near Carrollton. Kentucky American Water withdraws from the river upstream of Lexington, treating the water at its Lexington water treatment plant before distribution across Fayette County.

The Kentucky River basin drains a mix of terrain: limestone-rich Bluegrass Region geology in the central part of the state, and the sedimentary rock formations of eastern Kentucky upstream. That limestone and dolomite geology contributes the dissolved calcium and magnesium that produces Lexington's moderate hardness. Unlike the deep glacial-drift aquifers that supply many Indiana cities with very high hardness, surface water from the Kentucky River is softened somewhat by treatment and naturally by the river's dilution capacity, producing the 7 GPG reading at the tap.

Kentucky American Water's source water assessment, required under the Source Water Protection Program, rates the Kentucky River at Lexington's intake as having moderate susceptibility to contamination. Agricultural runoff (pesticides and nitrates), combined sewer overflows, and industrial discharges upstream are the primary documented risks. The utility publishes an annual source water assessment summary as part of its CCR. (Source: Kentucky American Water CCR, available at amwater.com/kyaw.)

Water hardness in Lexington: numbers and market comparison

The USGS uses calcium carbonate concentration to classify water hardness: soft is below 60 mg/L (3.5 GPG), moderately hard is 61 to 120 mg/L (3.6 to 7 GPG), hard is 121 to 180 mg/L (7 to 10.5 GPG), and very hard is above 180 mg/L. Lexington's reported 120 mg/L sits at the upper boundary of moderately hard, which in practical terms means:

• Visible white deposits on faucet aerators and showerheads within months of installation
• Reduced efficiency in water heaters as calcium carbonate scale builds on heating elements
• Shortened appliance lifespan for dishwashers and washing machines
• Soap that requires more product to lather effectively

The table below compares Lexington to the other markets Aqua Otter serves in Kentucky and surrounding states, using each city's most recent publicly available CCR or USGS data.

Sources: Individual utility Consumer Confidence Reports; EPA UCMR5 public data (epa.gov/dwucmr); waterhardness.org; USGS National Water Quality Assessment. CCR data reflects most recent published year per utility.

For homeowners comparing Lexington to Indianapolis or Fort Wayne: the hardness difference is significant. At 7 GPG versus 18 to 22 GPG, Lexington water will scale fixtures noticeably more slowly and is easier on appliances without treatment. Many Lexington households find a smaller softener or no-salt conditioner adequate where Indiana households need full-sized ion-exchange equipment. See our comparison of water softeners versus no-salt conditioners to understand which approach fits moderate-hardness situations.

Chloramine disinfection: what it means at your tap

Kentucky American Water uses chloramine rather than free chlorine as its secondary disinfectant. Chloramine is formed by combining chlorine with a small amount of ammonia. Kentucky American Water's CCR confirms: "Chloramines are a Kentucky and federally approved alternative to free chlorine for water disinfection." (Source: Kentucky American Water CCR, amwater.com.)

The practical effects for Lexington homeowners differ from free-chlorine markets like Indianapolis or Nashville:

• Chloramine does not off-gas. Leaving water to sit in an open pitcher will not reduce chloramine the way it reduces free chlorine. Standard activated carbon filters are only partially effective. Catalytic activated carbon (such as catalytic coconut shell or bituminous coal carbon) is required for effective chloramine reduction in a whole-house filter.
• Chloramine forms different byproducts. Free chlorine primarily forms trihalomethanes (TTHMs) and haloacetic acids (HAAs). Chloramine can form iodoacids and nitrosamines in addition to TTHMs and HAAs, though typically at lower concentrations of the regulated TTHM/HAA compounds. Kentucky American Water reports TTHM and HAA5 levels in its CCR, both required to remain below EPA regulatory limits.
• Dialysis patients require pre-treatment. Chloramine is toxic to patients on dialysis and cannot be used in dialysis machines. Dialysis centers handle this at their facility; home patients receiving dialysis at home should consult their care team about specific water treatment requirements.
• Fish tank owners should not use tap water directly. Chloramine is harmful to fish and does not dissipate with aeration. Water conditioners specifically rated for chloramine removal are required before use in aquariums.

For drinking water treatment, a reverse osmosis system removes chloramine effectively through the membrane plus any activated carbon pre-filter stages. A whole-house catalytic carbon filter addresses chloramine across all taps and appliances. See how our systems work for a comparison of treatment approaches.

PFAS in Lexington water: what the EPA UCMR5 data shows

The EPA's fifth Unregulated Contaminant Monitoring Rule (UCMR5) required public water systems serving more than 3,300 people to test for 29 PFAS compounds between January 2023 and December 2025. Kentucky American Water completed its monitoring rounds in 2023 and reported results to EPA. The table below summarizes the detections from UCMR5 public records.

Source: EPA UCMR5 data, 2023 monitoring round. Via toxinscout.com (PFAS screening, Lexington KY) and waterutilityreport.com/pfas-watchlist/utility/KY0340250, both citing EPA UCMR5 public records. PFOA and PFOS (the two compounds with the tightest new 4 ppt EPA MCLs) were not detected above minimum reporting limits.

Two things stand out from this data. First, PFOA and PFOS, the two most studied and most tightly regulated PFAS compounds under the 2024 EPA rule (4 ppt MCL each), were not detected above minimum reporting limits in Lexington's system. Second, the five compounds that were detected (6:2 FTS, PFBA, PFPeA, PFHxA, PFBS) are shorter-chain or alternative PFAS compounds for which current EPA limits are either nonexistent or very high. PFBS, for instance, has an EPA health advisory at 2,000 ppt, and Lexington's detection of 3.6 ppt is 555 times below that level.

For context on how Lexington's PFAS picture compares to Indiana, see our analysis of Indiana PFAS in drinking water under EPA UCMR5. For homeowners who want precautionary protection regardless of current limits, an NSF/ANSI 58-certified reverse osmosis system reduces PFAS at the kitchen tap. Independent testing by NSF International shows RO systems removing 90 percent or more of many PFAS compounds. (Source: NSF International PFAS treatment guide, nsf.org.)

Lead and older plumbing in Lexington

Kentucky American Water conducts Lead and Copper Rule tap sampling at selected residential sites across its service area and publishes the 90th percentile results in its annual CCR. The utility treats distributed water with corrosion control to minimize lead dissolution from plumbing materials in contact with the water.

For Lexington homeowners, the relevant risk factors mirror those in every other market we serve: homes built before 1986 may contain lead solder in copper plumbing joints, lead service line segments (though Kentucky American Water has undertaken service line replacement programs), and older brass fixtures that contain lead. The water itself, properly treated, is not the source; lead enters the water from plumbing materials it contacts.

If your home was built before 1986, the most reliable approach is a kitchen tap test from a state-certified laboratory. An NSF/ANSI 53-certified filter or an under-sink reverse osmosis system certified for lead reduction handles the concern at the point of use. Our free in-home water test can check for lead indicators and other contaminants specific to your address.

What Lexington homeowners should treat for

Based on the public data above, here is the prioritized treatment stack for a typical Lexington city-water home in 2026:

For Lexington homes on a private well rather than city water, the treatment approach shifts substantially. Kentucky wells in Fayette County and surrounding areas can show elevated iron, manganese, hardness, and bacteria. Our well water testing guide explains what to test for and how to interpret results. Our well water treatment systems are sized for the specific contaminants found in your test, not a generic package.

For a maintenance perspective on keeping treatment equipment running in a moderate-hardness environment like Lexington, see our water softener maintenance schedule for Indiana and Michigan markets (the principles apply equally to Kentucky systems). The softener versus no-salt comparison is also worth reading for 7 GPG situations.

Related water quality data for other Aqua Otter markets

We have published similar originate data pieces for several of the other cities we serve. These are useful if you are comparing water quality across locations or moving between markets:

• Raleigh, NC water quality 2026 (very soft, Falls Lake source, chloramine)
• Columbus, OH water quality 2026 (moderately hard, Scioto River, chloramine)
• Nashville, TN reverse osmosis guide 2026 (soft water, Cumberland River)
• Michigan cities hard water guide (Detroit, Grand Rapids, Ann Arbor, Kalamazoo)
• Michigan water hardness map 2026 (county-by-county GPG data)
• Indiana PFAS in drinking water (UCMR5) (56 Indiana utilities, 19 exceeded the federal MCL)
• Hard water in Indiana (statewide hardness patterns and treatment context)

Frequently asked questions about Lexington, KY water quality