Is Columbus, OH Tap Water Safe to Drink?

Where Does Columbus Get Its Water?

Columbus, OH is served by several public water systems drawing from surface water sources in central Ohio. The largest is Columbus Public Water System, which supplies most of the city. Other providers serving parts of the broader area include Aqua Ohio (Blacklick and Lake Darby systems), Bexley City Public Water System, Del-Co Water Company, Jefferson Water and Sewer District, and Sanitary District No. 4.

Columbus Public Water System operates multiple recognized treatment plants: Alum Creek Water Treatment Plant, Dublin Road Water Treatment Plant, Hap Cremean Water Treatment Plant, Olentangy Water Treatment Plant, and Parsons Avenue Water Treatment Plant. These facilities collectively handle the water supply for the city and surrounding communities.

Smaller providers like Del-Co Water Company and Aqua Ohio serve outlying portions of the Columbus metropolitan area and draw from their own sources and well-based systems, supplementing the primary surface water infrastructure.

How Is Columbus Tap Water Treated?

Columbus-area water treatment plants use a multi-step process that includes coagulation, biological treatment, filtration (including membrane filtration), adsorption, and ion exchange. Some facilities also apply powdered activated carbon and other adsorption steps to remove dissolved contaminants before water reaches the distribution system.

Disinfection at these plants includes ozone treatment, free chlorine, and ultraviolet light, used in combination to neutralize bacteria, viruses, and other pathogens. A residual disinfectant is maintained through the pipes to keep water safe as it travels to your tap.

The variety of treatment technologies across Columbus-area utilities reflects differences in source water quality and local infrastructure. Not every plant uses every method, but together the system represents a layered approach to water safety.

What's in Columbus Tap Water?

The most significant finding from recent EPA testing is PFPeA, a PFAS compound (a type of synthetic chemical sometimes called 'forever chemical'). The highest detected level was 0.017 µg/L, against EPA's limit of 0.003 µg/L. PFPeA was detected across all 35 ZIP codes sampled, and 31 of those ZIPs had levels above EPA's limit. This is the primary water quality concern for Columbus.

Several other PFAS compounds were also detected: PFHxA at a peak of 0.0182 µg/L, PFBA at 0.017 µg/L, and PFBS at 0.0111 µg/L. None of these three exceeded their respective EPA benchmarks in the sampled ZIPs, though their presence indicates a broader PFAS pattern in the water. Lithium was detected at a peak of 12.9 µg/L, above a non-regulatory health reference level of 10 µg/L, in 4 of the 39 ZIPs where it was found.

PFAS compounds are industrial and consumer chemicals that persist in the environment and can accumulate in water sources. Lithium occurs naturally in some groundwater and surface water at low levels. The sources of these specific detections in Columbus-area water have not been identified in the available data.

Health Risk Profile for Columbus

PFPeA is subject to an EPA enforceable drinking water standard of 0.003 µg/L. The peak measured level in Columbus-area water was 0.017 µg/L, nearly six times that limit. Long-term exposure to PFAS above EPA limits is associated with effects on the immune system, thyroid, liver, and kidney function, and may affect reproductive health. The other PFAS detected (PFHxA, PFBA, PFBS) were below their respective benchmarks in the sampled data.

Lithium's 10 µg/L reference level is a non-regulatory health reference benchmark, not a federal enforceable maximum. No federal MCL (maximum contaminant level) for lithium in drinking water currently exists. The peak detected level of 12.9 µg/L was found in a small number of areas. Infants, pregnant individuals, and people with kidney conditions may be more sensitive to elevated lithium exposure.

For PFAS, the most effective home filtration options are certified to NSF/ANSI 58 (reverse osmosis) or NSF/ANSI P473 (for PFAS specifically on activated carbon filters). NSF/ANSI is an independent third-party certification program, so look for that label on the filter packaging. Because Columbus water also uses chlorine-based disinfection, a filter with NSF/ANSI 42 certification can also help with taste and odor. Point-of-use filters at the kitchen tap are the practical choice for most households.

The EPA's PFAS limits are newly established and science on some shorter-chain PFAS compounds continues to develop. For the compounds without current enforceable limits, EPA is still evaluating health effects. If you are in a sensitive group, a point-of-use reverse osmosis or certified PFAS-reduction filter is a reasonable precaution given the current data.