Columbus tap water is safe to drink and consistently meets or exceeds all federal and state regulatory standards set by the Environmental Protection Agency (EPA) and the Ohio EPA. The city’s public utility system employs a multi-barrier approach to treat water from various sources before it is delivered to over one million residents. While the municipal water is high-quality upon leaving the treatment plant, localized risks, primarily from aging infrastructure on private property, can impact water safety at the tap. Understanding the source, treatment, and potential vulnerabilities allows residents to make informed decisions about their home water use.
Water Sources and Treatment Systems
Columbus draws its water from a mix of surface water and groundwater sources. The majority comes from surface sources, including the Scioto River (feeding Griggs and O’Shaughnessy Reservoirs) and Big Walnut Creek (supplying the Hoover Reservoir). The city can also draw from Alum Creek Reservoir during drought. These reservoirs provide approximately 90% of the daily water demand.
This surface water undergoes a multi-step treatment at the Dublin Road and Hap Cremean Water Plants. The process begins with coagulation and sedimentation to remove suspended solids, followed by softening using lime to reduce hardness. The water is then treated with ozone and passed through granular activated carbon (GAC) filters, which remove organic compounds, taste, and odor-causing substances. Final steps involve ultraviolet (UV) light disinfection and the addition of chlorine to prevent microbial growth, along with a corrosion inhibitor to protect pipes. A smaller portion of the supply comes from groundwater wells, treated at the Parsons Avenue Water Plant.
Current Safety Status and Regulatory Compliance
The quality of Columbus’s drinking water is affirmed by its adherence to federal and state guidelines. The EPA establishes Maximum Contaminant Levels (MCLs), and the Ohio EPA enforces these standards locally. Columbus Public Utilities operates to meet and often surpass these regulated health standards, reporting monitoring results to state and federal agencies.
Official monitoring data shows the municipal water supply is in full compliance with federal health-based drinking water standards. This compliance is documented in the annual Consumer Confidence Report (CCR), a publicly available document summarizing the previous year’s testing results. The CCR details all regulated contaminants detected and their levels compared to the established MCLs. Residents can access the most recent CCR on the Columbus Public Utilities website to review the official metrics.
Managing Specific Contaminant Risks
While the treated water leaving the plants is safe, risks can arise from the city’s aging distribution network and private plumbing. The primary concern in older homes is Lead Service Lines (LSLs), which can leach lead into the water after it leaves the treatment plant. Lead is not in the source water, and the city maintains a corrosion control program that coats the inside of pipes to prevent leaching.
Despite the corrosion control, the city is addressing this structural risk, with a goal of replacing all lead and galvanized service lines by 2037. Columbus is also monitoring for emerging contaminants, such as Per- and Polyfluoroalkyl Substances (PFAS), which are human-made chemicals. The city’s results indicate the water currently meets the proposed federal drinking water standards for these compounds, though testing is ongoing to anticipate future regulations.
Personal Measures for Enhanced Safety
For residents in older homes or those desiring extra protection, several personal steps can enhance water quality at the tap. If water has been sitting for several hours (such as overnight), flush your cold water tap for at least 30 seconds before using it for drinking or cooking. This action clears water that may have picked up trace contaminants from internal plumbing.
Another option is to install a certified home filtration system, ranging from simple pitcher filters to complex under-sink reverse osmosis units. Ensure the filter is certified by an independent body, such as NSF International, to remove specific contaminants of concern, particularly lead. Residents who wish to know the quality of the water entering their home can also obtain a private testing kit from a state-certified laboratory.