Aqua Ohio - Marion

• Marion's 1924 sewage treatment plant, designed by engineer George Gascoigne, was noted at the time as one of the few plants in Ohio achieving complete treatment year-round.
• Aqua Ohio's Marion system traces its corporate lineage to the Consumers Ohio Water Company, which was later renamed Aqua Ohio, Inc.
• In December 2025 a citywide complaint about earthy-tasting tap water led Aqua to shut off its primary river intake entirely and run Marion on primarily well water; the utility never identified the specific compound…
• About 3 million of the 8.5 million gallons Marion's wastewater plant treats each day is stormwater, so on a typical day roughly a third of what the plant handles is rain rather than sewage.

• 1903-1905Marion's first sewage treatment plant opened in 1903 and was operational by 1905; the State Department of Health soon judged it inadequate because it was polluting local waterways.
• 1924A modern replacement sewage plant designed by consulting engineer George Gascoigne went into service, one of the few plants in Ohio achieving complete treatment year-round.
• 2025-12Organic compounds in the water feeding the Marion Water Treatment Plant caused a citywide taste-and-odor complaint; Aqua adjusted intakes and treatment, shifted to primarily well water, and increased…
• 2026-07PUCO approved an Aqua Ohio rate increase of about $9.5 million in additional annual water revenue (down from the $13.4 million requested) plus $1.04 million for wastewater, affecting Marion customers.

How it is treated

Aqua Ohio's Marion plant treats surface water drawn from a river intake on the Scioto/Little Scioto system, supplemented by local groundwater wells. Operators can take the primary river intake out of service and run on primarily well water while adjusting treatment, as they did during the December…

Water pressure

Not published in sources reviewed.

PUCO case 25-0594-WW-AIR: Aqua Ohio requested $13.4M in additional annual water revenue for its roughly 47,000 Ohio customers; PUCO approved about $9.5M (plus $1.04M wastewater)…

EPA compliance record

Lead at the tap: 90th-percentile result 3.7 ppb in 2023 (action level 15 ppb).

EPA record: no health-based violations since 2015.

Recent and current work

• Emergency source switch and enhanced treatment · 2025 · completed
  After the December 2025 odor event, Aqua ceased using the primary river intake, ran on primarily well water, adjusted treatment and increased testing.

Planned or needed

• Aqua Ohio system-wide infrastructure investment tied to PUCO case 25-0594-WW-AIR · 2026 · planned
  The July 2026 rate increase funds infrastructure spending across Aqua Ohio's territories. No Marion-specific project was identified in sources reviewed.

The Marion plant's river intake is exposed to upstream agricultural runoff and treated wastewater effluent, which surfaced in December 2025 when organic compounds forced Aqua off the primary river intake and onto primarily well water for several days. Local reporting also describes historical difficulty controlling disinfection…

Sanitary

The City of Marion, not Aqua, runs the sanitary sewers and wastewater treatment plant, discharging to the Little Scioto River. The plant dates to 1903-1905, was rebuilt in 1924, modified in 1953, and by 1956 ran methane digesters for heating at 5.4 MGD. A 1978 activated sludge project cost $12.5 million and raised capacity to 10.5 MGD; a…

Storm

No separate stormwater utility was identified, but roughly 3 million gallons of stormwater per day reaches the wastewater plant — about a third of its 8.5 MGD average flow — indicating substantial inflow and infiltration into the sanitary system.

Compiled from the utility's own reports and public records, then independently re-checked against primary sources.