What a Certified Laboratory Test for This Constituent Reports and How to Read It

Lead 90th Percentile Reports Indicate Distribution System Levels

The EPA sampling in Lancaster’s public water system measures lead concentrations at the 90th percentile, reflecting lead in tap water after water leaves the treatment plant and passes through pipes and fixtures. This is not a source-water test but a snapshot of typical lead levels where people use water.

Distribution Sampling Reflects Plumbing, Not Source Water

Since lead can enter water through plumbing, a lab test showing 0.007 mg/L at the 90th percentile means most homes tested had lead concentrations at or below this value on that date. Individual homes may vary significantly, so personal testing is needed for specific conditions.

What 'Detected', 'Median' and 'Range' Mean in the Sampling Record on This Page

'Detected' Means Measured Presence, Not Exceedance

The EPA record notes the presence of lead as detected at measurable levels but does not classify this as a violation or health threat on its own. Detection signifies the measurement capability of instruments, not a safety hazard.

Median and Range Describe Typical and Variable Levels

The 90th percentile is a statistical marker used here instead of median, highlighting the upper end of lead concentrations found during testing. Range information can illustrate variability in the system but is not detailed in this record.

What the Measured Range Means Against the Relevant Federal Standard, and What It Does Not Mean

EPA Has No Health-Based Violations Recorded for Lancaster

The public water system serving Lancaster has zero EPA health-based violations on record, which means monitored lead concentrations have stayed within federally acceptable levels. This status reflects regulatory compliance, not individual home water quality.

Below Regulatory Action Level Does Not Guarantee Absence of Lead

Even with no violations, some detection is possible, and only a home-specific test can confirm lead presence or absence. The data do not imply safety or risk for any individual residence, only regulatory status for the system.

How to Compare This Area’s Record with a Neighboring County’s Without Overreading It

Sampling Scope and Population Affect Comparisons

Lancaster’s system serves about 120,000 people across nearly 50,000 connections, drawing from surface water sources. Neighboring counties may have different source types, system sizes, and sampling frequencies, which influence reported results.

Avoid Assuming Uniform Conditions Across Regions

Variations between public water systems can exist due to geology, infrastructure, and treatment methods. Government records provide system-level data and should not be used to infer conditions in a specific home or generalize without considering source and system differences.

How the Constituent Enters Groundwater or the Distribution System in This Region

Lead Enters Through Plumbing Materials, Not Source Water

Lead detected in Lancaster’s distribution system typically results from corrosion of plumbing components such as pipes, solder, and fixtures rather than the surface water source itself. Water treatment plants remove many contaminants but cannot eliminate lead leaching in-home plumbing.

Corrosion Control Is a Key Focus of Treatment

Water utilities often add corrosion inhibitors to reduce lead solubility, helping maintain lead concentrations below action levels. Understanding this process is critical when selecting treatment equipment for residential use.

Choosing Equipment to Meet Your Demand

For homes in Lancaster seeking comprehensive water conditioning that addresses typical city water characteristics, the Fleck City Whole-Home Protection System ships ready to configure with a capacity of 32,000 grains. This equipment class offers broad protection suitable for residential demand, helping manage municipal water traits effectively.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2025-09-30. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA SDWIS record for CITY OF LANCASTER (PA7360058), surface water supply, serving 120000 people: 0 health-based violations of 0 total; lead 90th percentile 0.007 mg/L