Wilmette

The Illinois EPA considers surface water supplies particularly vulnerable to contamination issues. Unlike groundwater, surface water lacks natural filtration, relying solely on dilution to reduce contaminant concentrations. This vulnerability necessitates mandatory treatment for all surface water sources throughout Illinois.

A specialized Great Lakes States workgroup developed protocols for evaluating water quality in these unique ecosystems. Their approach balances consistency with flexibility, accounting for the variable nature of these massive freshwater resources when determining source sensitivity and contamination susceptibility.

For Wilmette's water supply, sensitivity analysis shows the intake locations are positioned sufficiently offshore to minimize direct shoreline impacts. However, seasonal risks exist when wet-weather discharges from the North Shore Channel flow northerly, potentially compromising water quality. Data correlation between Evanston rainfall measurements, channel discharge timing, and Wilmette's coliform testing demonstrates this relationship clearly.

The proximity to major shipping lanes presents additional contamination risks should spills occur near intake points. Wilmette water officials actively participate in the West Shore Water Producers Association, where coordination regarding water quality incidents (spills, tanker leaks, invasive species) occurs during quarterly meetings.

To ensure tap water safety, EPA regulations limit contaminant levels in public water systems, similar to FDA requirements for bottled water. Water sources (both tap and bottled) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over land or underground, it dissolves naturally occurring minerals and, in some cases, radioactive materials, while also potentially collecting substances from animal presence or human activity.

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