Is Peoria, IL Tap Water Safe to Drink?

Where Does Peoria Get Its Water?

Peoria's tap water comes from a mix of surface water and groundwater sources. The primary surface water source is the Illinois River, which feeds the region's major treatment plants. Groundwater wells also supply portions of the service area, particularly for smaller utilities operating in and around the city.

The main surface water treatment facilities include the Illinois River Treatment Plant and the San Koty Treatment Plant, both operated by Illinois American Water. The Griswold Street Treatment Plant and the Dodge Street Wells serve additional parts of the community. Peoria Heights operates its own separate water system with several well-based treatment plants.

A smaller district, Pleasant Valley Public Water District, also serves residents in parts of the broader Peoria area. Each utility draws from its own source and maintains independent treatment and monitoring programs, though all are regulated under Illinois and federal EPA rules.

How Is Peoria Tap Water Treated?

The surface water plants use conventional treatment steps: coagulation to remove particles, followed by filtration to clarify the water before disinfection. Powdered activated carbon is used to address taste, odor, and certain organic contaminants that can come from river water. This multi-step process is standard for large utilities drawing from the Illinois River.

Disinfection at Peoria's plants uses free chlorine, which kills bacteria and viruses and keeps water safe through the distribution pipes to your tap. Some facilities in the area supplement with additional disinfection approaches as part of their treatment programs. A residual level of disinfectant is maintained in the pipes as required by federal rules.

The groundwater-sourced systems, including the Peoria Heights wells and Pleasant Valley's well plants, rely on disinfection and well-water-specific treatment. Because groundwater is generally more protected from surface contamination, these systems typically require less treatment for particles and organics, though they still monitor for a full range of contaminants.

What's in Peoria Tap Water?

The most notable finding in recent EPA testing is lithium. It was detected in all 29 ZIP codes mapped to Peoria, with a peak measured value of 20.8 µg/L. EPA has established a non-enforceable health reference level of 10 µg/L for lithium in drinking water, meaning the peak reading is more than double that benchmark. The most recent samples were collected in October 2024.

Several PFAS compounds were also detected. PFHxS reached a maximum of 0.014 µg/L, PFBA reached 0.0086 µg/L, and PFOS reached 0.0065 µg/L. None of these individual compounds exceeded their respective EPA regulatory limits in these samples, but their presence across all 29 ZIP codes means PFAS monitoring is ongoing and relevant to Peoria residents.

Lithium in drinking water typically enters from natural geological sources in the watershed or groundwater, not from human industrial activity in most cases. PFAS compounds, sometimes called forever chemicals, can originate from industrial discharges, firefighting foam use, or agricultural runoff upstream along the Illinois River and its tributaries.

Health Risk Profile for Peoria

Lithium is the primary concern here. EPA's health reference level for lithium is 10 µg/L, and this is not an enforceable federal maximum contaminant level; no federal legal limit for lithium in drinking water currently exists. Still, the peak detection of 20.8 µg/L in Peoria's water is more than twice that reference benchmark, which is the level EPA considers a starting point for potential health concern.

Developing fetuses, infants, and pregnant individuals face the greatest potential sensitivity to elevated lithium in drinking water, as lithium can affect thyroid function and fetal neurological development at higher exposures. People with kidney conditions may also be more sensitive. For these groups in particular, using a certified filter or an alternative water source for drinking and formula preparation is a reasonable precaution.

For lithium and PFAS together, a filter certified to NSF/ANSI 58 (reverse osmosis) is the most effective option for home use. NSF/ANSI is an independent third-party certification standard, so look for that label on the box or the manufacturer's product page. Reverse osmosis systems certified under NSF/ANSI 58 reduce a broad range of dissolved contaminants including lithium and most PFAS compounds. Pitcher-style filters certified to NSF/ANSI P473 can reduce some PFAS but are generally less effective against lithium.

For the PFAS detected, none of the individual compounds exceeded EPA regulatory limits in these samples. The science on combined low-level PFAS exposure is still developing, and EPA continues to update its guidance. For most healthy adults, the PFAS levels measured here are below current federal action thresholds, but continued monitoring is warranted.