Delaware City

• Delaware pushes its river water through two membrane stages, ultrafiltration then nanofiltration, a far more aggressive filtration train than most Ohio river systems run.
• Well water is treated on a completely separate line - iron and manganese pressure filters, then its own nanofiltration - before the two finished streams meet in one clearwell.
• Backup wells sit both under the plant and in a wellfield on Penry Road two miles north, so a bad day on the Olentangy need not be a bad day at the tap.
• Del-Co Water Company, the big regional nonprofit serving the countryside around Delaware, is a separate utility on entirely different sources - easy to confuse with the city plant.

• 1808Town of Delaware platted; the modern water system comes well over a century later.
• 2024City completes its federally required lead service line inventory in November and begins notifying affected customers.
• 2025Ohio EPA records a Tier 3 monitoring-and-reporting violation for the January 2025 lead service line notification period.
• 2026That violation is resolved in January; the city states it was a notification requirement, not a drinking water quality problem.

How it is treated

River water gets aluminum chlorohydrate coagulation, settling, then ultra- and nanofiltration membranes; well water gets iron/manganese pressure filters plus its own NF membranes. The two streams merge, then chlorine, fluoride and a corrosion inhibitor.

Water pressure

Not published; no psi figure or pressure-zone map found. The city cites 190 miles of water line and 2,000 fire hydrants in its distribution system.

No per-1,000-gallon schedule is published online. Bills combine water, wastewater, stormwater and curbside refuse; delinquent bills draw a 5% penalty.

EPA compliance record

Lead at the tap: 90th-percentile result 0 ppb in 2024 (action level 15 ppb).

EPA record: no health-based violations since 2015.

1 violation of any kind logged since 2020, 1 of them paperwork (monitoring, reporting, public notice or consumer report).

Recent and current work

• Lead service line inventory and customer notification · 2024-2026 · completed
  Nov 2024 inventory and required notices; a Tier 3 monitoring/reporting violation for Jan 2025 was resolved in Jan 2026.

The Olentangy is a developed farm-and-suburb watershed and Ohio EPA rates the city's supply as highly susceptible to contamination; atrazine turns up every year. Deep wells under the plant and a Penry Road wellfield give a groundwater fallback most river-fed Ohio systems lack.

Sanitary

The city's own sewer division collects and treats wastewater and returns it to the Olentangy River, over 175 miles of sewer line, 3,250 manholes and 12 pump stations. Plant name, capacity and any CSOs or consent decree were not confirmed.

Storm

Separate storm sewers, billed as a stormwater charge on the utility bill. The city maintains a stormwater management plan and an illicit discharge detection and elimination plan under federal MS4 rules.

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