Rock Hill, Fort Mill and Tega Cay water: one plant, five reports

One treatment plant, several water systems

The City of Rock Hill draws water from intakes on Lake Wylie and the Catawba River and treats it at its Cherry Road plant.^[source] The Town of Fort Mill buys its water from Rock Hill.^[source] Tega Cay buys from Fort Mill, so its water also comes from Rock Hill.^[source] York County's East and West distribution systems buy from Rock Hill too, and the West report says that system is supplemented by Charlotte Water.^{[source][source]}

Each of those systems runs its own pipes, takes its own lead and byproduct samples, and publishes its own annual report. So the source water is shared, but some results differ by system. Which report is yours depends on who sends your water bill; our water lookup tool can help, and EPA's service-area boundaries place the Lake Wylie community in York County's West system.^[source]

Disinfectant: chlorine dioxide plus chlorine

Rock Hill's 2025 report lists both chlorine and chlorine dioxide in its data table, and chloramine isn't listed.^[source] The downstream reports describe their own residuals differently: Fort Mill, Tega Cay and both York County reports list only a chlorine residual measured in their own pipes.^{[source][source][source]}

Either way, if your water tastes or smells of chlorine, that's the disinfectant doing its job. If it bothers you, carbon filtration for chlorine taste is the usual fix, and it's a preference, not a necessity.

Hardness: soft, so skip the softener pitch

The U.S. Geological Survey calls water under 60 mg/L soft.^[source] At 35 ppm at most, Rock Hill water is comfortably soft, and Tega Cay and both York County reports show the same figure from Rock Hill's data.^{[source][source]} If someone recommends a water softener for this water without testing it, that's a red flag. We cover it on what we won't sell you and in do I need a water softener?

Lead and disinfection byproducts

Rock Hill's lead 90th percentile was 2 ppb in its 2023 sampling round, with no sites above the 15 ppb action level.^[source] Fort Mill's 2024 round had a 90th percentile of 0 ppb, with one sample above the action level.^[source] That pattern is common: a system can look clean overall while an individual home with older plumbing tests high. If your home is older or you're simply curious, a home lead test answers it for your faucet.

For trihalomethanes, Rock Hill's highest running annual average in 2025 was 52 ppb against the 80 ppb federal limit.^[source] Fort Mill's report shows individual samples up to 93.2 ppb, but compliance is based on running averages and the report marks no violation.^[source]

PFAS

Rock Hill's 2025 report lists two unregulated PFAS from federal UCMR5 sampling in 2024: PFHxA at an average of 4.0 ppt and PFPeA at 4.6 ppt.^[source] PFOA and PFOS aren't listed in the table. The report says non-detects from that sampling were left out of the table, but it doesn't name PFOA or PFOS specifically, so we don't treat that as a confirmed result. EPA's enforceable limits for PFOA and PFOS are 4.0 parts per trillion; other proposed PFAS limits are under review.^[source] See PFAS in Charlotte-area tap water for the regional picture.

Violations, as each report lists them

• Rock Hill: the report states that no violations occurred during the reporting period.^[source]
• Fort Mill: the report states its 2025 water met all state and federal water quality standards.^[source]
• Tega Cay: the report lists a Lead and Copper Rule monitoring violation for 10/01/2025 to 03/23/2026. It explains that a laboratory processing error meant 29 of the 30 required samples were analyzed, and that there were no lead or copper exceedances.^[source]
• York County East: the report lists three monitoring violations for November 2025, covering disinfection byproduct, coliform and filter monitoring, each described as a failure to test for the period indicated.^[source]
• York County West: the report lists a notification violation for 05/14/2025 to 06/10/2025, for failing to notify regulators of positive E. coli sample results, and its coliform table lists 2 positive samples.^[source]

Monitoring and notification violations are about testing and paperwork deadlines, and the reports explain them in their own words. Parts of the York County reports don't fully agree with each other (for example, tables marked "no violation" next to listed violations), so if any of this matters to you, call York County Utilities and ask directly. You can also see each town's details on the Rock Hill, Fort Mill, Tega Cay and York County pages.