Lincolnshire purchases all of its municipal drinking water from the City of Highland Park. Highland Park draws raw surface water from Lake Michigan through a 54-inch intake pipe located approximately one mile offshore and about 30 feet below the surface. Two smaller intake pipes may also supply the treatment plant.

After filtration and treatment in Highland Park, the water travels to Lincolnshire through a 30-inch transmission main. It reaches the Eastside Reservoir, where it is pumped into the Village distribution system. Lincolnshire also operates the Westside Reservoir. Together, the two facilities provide up to 4.6 million gallons of storage capacity.

The Village maintains approximately 76 miles of water main, 958 hydrants, and more than 1,500 valves. During 2025, Lincolnshire supplied more than 424 million gallons to residential and commercial customers. The report does not provide a detailed step-by-step description of Highland Park’s treatment process, so no additional treatment details are inferred here.

Lincolnshire’s 2025 Annual Drinking Water Quality Report states that the Village’s tap water met all applicable U.S. EPA and Illinois EPA drinking-water standards. The report’s violation summary states that no violations occurred during the 2025 reporting year.

The report includes both Highland Park supplier data and Lincolnshire-specific data, with Lincolnshire results marked by an asterisk.

For the Highland Park source-water system, the 2025 lead result was 11 parts per billion at the 90th percentile, below the 15-parts-per-billion action level. Five individual samples exceeded the action level, but the report identifies no violation. The corresponding copper result was 0.13 parts per million, below the 1.3-parts-per-million action level, with no samples exceeding that level.

Lincolnshire’s own most recent lead and copper results shown in the table were from 2023. The Lincolnshire lead result was reported as 0, with no action-level exceedances, and the copper result was 0.199 parts per million, also with no exceedances. The report further states that Lincolnshire has no lead service lines and that the Village is on a triennial lead-and-copper monitoring schedule, with its next sampling planned for June through September 2026.

The 2025 tables also show no violations for turbidity, fluoride, barium, sodium, chloride, magnesium, sulfate, hardness, calcium, alkalinity, total dissolved solids, hexavalent chromium, total trihalomethanes, haloacetic acids, chlorine, chloramines, or total-organic-carbon treatment requirements.

The report specifically addresses occasional taste and odor changes. It explains that during summer and early fall, microscopic organisms such as algae in Lake Michigan can sometimes create an earthy taste or odor. Temperature changes and heavy rainfall may also affect taste. According to the report, these changes do not affect water safety.

The report also notes that brown or yellow water may occasionally occur after water-main installation, hydrant flushing, main breaks, or system repairs. Iron or mineral deposits inside pipes can become dislodged during this work. Household plumbing may also contribute when discoloration occurs frequently or is most noticeable when water is first used in the morning.

Cloudy or milky water is described as commonly resulting from dissolved oxygen coming out of solution as the water warms. The report states that this condition is more common in winter, generally clears within 30 to 60 seconds, and does not affect water quality.

The report lists total hardness at 140 parts per million as calcium carbonate and describes the Highland Park supply as averaging approximately 8 grains per gallon. Hardness is presented as a mineral-content characteristic, not a drinking-water violation.

The Illinois EPA considers all surface-water sources susceptible to potential pollution because contaminants can migrate toward treatment-plant intakes. The report identifies sediment, shoreline erosion, stormwater discharge, and wet-weather sewer overflows as possible influences on Highland Park’s Lake Michigan source water.

The report states that Lincolnshire has no lead service lines. It nevertheless advises residents that lead can enter water through household plumbing components. When water has been standing for several hours, the Village recommends flushing the tap for 30 seconds to two minutes before using it for drinking or cooking. Residents concerned about lead may also choose to have their water tested.

Lincolnshire sampled for unregulated contaminants, but the report does not publish individual results. It explains that these contaminants do not yet have EPA drinking-water standards and directs residents to the Village Utilities Superintendent for access to the data. Because no specific PFAS or other unregulated-contaminant results are provided, no such findings are claimed on this page.

The report also advises that immunocompromised people, some elderly adults, infants, and others who may be more vulnerable to microbial contaminants should consult their healthcare professionals.