Sources and plants
Columbus uses surface water from the Scioto River and Big Walnut Creek, plus groundwater from sand and gravel in the Scioto River valley at Parsons Avenue. Dublin Road serves the northwest and southwest from Griggs and O'Shaughnessy. Hap Cremean serves the OSU area and the north from Hoover Reservoir. Parsons Avenue serves the southeast from wells.
Treatment includes lime softening, filtration, and disinfection. The surface-water plants also use UV. Iron in the finished-water discussion is not a reason to buy a well-style iron filter for a Columbus tap.
Nitrate, sodium, and sulfate in 2025
Nitrate MCL is 10 ppm. Dublin Road reached 6.3 ppm (range ND–6.3). Hap Cremean was 1.4 ppm. Parsons Avenue was non-detect. The report ties elevated Scioto nitrate to agricultural runoff. Columbus added anion-exchange nitrate removal at Dublin Road.
Sodium averages: Dublin Road 69.2 ppm, Hap Cremean 19.2 ppm, Parsons Avenue 86.7 ppm. Sulfate averages: 129.3, 54.5, and 207.8 ppm. The sulfate secondary standard is 250. These are drinking-water details for reverse osmosis conversations, not proof the water fails a standard.
Lead and PFAS
Lead, 2023 sampling: 90th percentile 1.3 ppb, action level 15. Zero of 50 sites were over the action level. Water leaving the plants is below detection. Columbus offers free drinking-water lead testing and, in 2024, a lead service line program to remove public and private lead and galvanized lines by 2040.
PFAS: tested since 2019, with some results near detection limits. The city says the plants would meet the federal standards described in its materials. Monitoring and compliance dates in the 2025 report were 2027 and 2029. A home softener does not remove PFAS. Certified reverse osmosis or carbon is the equipment topic, as an option, not a requirement.
Disinfection byproducts and the filter question
2025 plant-average TTHM was 58.4, 64.1, and 27.6 ppb (MCL 80). HAA5 was 22.4, 37, and 4.7 ppb (MCL 60). Atrazine showed up at Dublin Road and Hap Cremean well under the 3 ppb MCL. Cryptosporidium was detected in 2 of 12 raw Scioto source samples in 2025, before treatment.
Asked whether customers need a home filter, Columbus says no, and points people who still want one toward NSF/ANSI or WQA certified equipment. That is the line this site follows.
Questions people ask
Is Columbus tap water safe to drink?
The city’s report is the document that answers that, and the city says a home filter is not required for safety. This page quotes the 2025 figures and links the PDF.
Where is the Columbus water quality report?
The 2025 consumer confidence report is published by Columbus Water & Power. The source list on this page links the PDF.