St. Marys City

Who runs it

EPA's record describes St. Marys City as owned by a local government. It has 4,096 service connections and serves 9,356 people.

EPA classes it as a community water system, one that serves the same residents all year.

EPA's record says it has substantially implemented source water protection under Ohio's program, dating the program from 2025. Its office telephone on EPA's record is 419-394-4114.

Source: EPA Safe Drinking Water Information System (SDWIS), water system record.

How the water is treated

EPA's treatment table registers these steps for St. Marys City: coagulation and settling, chlorine disinfection, lime softening, and sand or media filtration.

The list is what each system registered with EPA for treatment plants EPA still shows as active, and it can lag a plant upgrade.

Source: EPA Safe Drinking Water Information System (SDWIS) treatment table (EPA Envirofacts, pulled September 2026).

Violations

EPA counts 1 health-based violation for St. Marys City since 2015. Health-based means a contaminant above its legal limit or a required treatment step not carried out. It falls into 1 separate problem (one contaminant or rule in one year); the table lists it.

EPA logs 3 violations of any kind since 2020: 2 for a report, record or notice that was missing, late or incomplete (the yearly water quality report, a public notice, lead line records); 1 health-based.

Source: EPA Safe Drinking Water Information System (SDWIS) violation records: health-based violations with compliance periods beginning in 2015 or later, all violations from 2020 or later (EPA Envirofacts, pulled September 2026).

Lead and copper at the tap

In the sampling period ending December 2025, the 90th-percentile lead result at St. Marys City was 0 ppb, under both the current 15 ppb action level and the 10 ppb level that applies from 2027. A result of 0 means at least nine in ten of the homes sampled had no lead detected.

The highest result on file is 2.3 ppb, in the period ending December 2017.

EPA has 8 sampling periods on file for St. Marys City since 2016, the first ending in 2017; no period was above 10 ppb.

Every water system has to inventory its service lines, the pipes from the main to each building. In the inventory St. Marys City sent EPA, 4,766 lines are counted.

Systems sample taps in the homes most likely to have lead pipes or solder. The 90th-percentile result is the level nine in ten of the sampled homes were at or below. Lead comes mostly from service lines and house plumbing, not the source water, so a low result for the system does not clear an old house.

EPA's dashboard status for this inventory: reported all required service line types.

Source: EPA Safe Drinking Water Information System (SDWIS) lead and copper 90th-percentile results (EPA Envirofacts), sampling periods ending 2016 or later; EPA's service line inventory dashboard, Ohio's 2026 Q2 submission.

PFAS

EPA's fifth national round of testing (UCMR 5) took 2 samples of the water entering the pipes of St. Marys City in 2024 and measured 29 PFAS. No PFAS was detected, PFOA and PFOS (federal limit 4 ng/L each) among them.

Ohio EPA's own statewide sampling tested 1 plant of St. Marys City (latest sample September 2020). Not one of the six PFAS tested (PFOA, PFOS, PFHxS, PFNA, GenX and PFBS) was detected.

PFAS are the 'forever chemicals' from firefighting foam, plating shops and non-stick coatings. Results are for water leaving the plant, not your tap.

Source: EPA UCMR 5 occurrence data (final release, August 2026); Ohio EPA statewide PFAS sampling, 2019 to 2021, and its sampling status map.

Disinfection byproducts

Chlorine that disinfects water also reacts with organic matter to form byproducts. Two groups have federal limits: total trihalomethanes (TTHM, 80 µg/L) and five haloacetic acids (HAA5, 60 µg/L), judged on running yearly averages at each sampling site.

For TTHM, the average of St. Marys City's samples in 2019, the last year it was sampled, was 0 µg/L. The worst yearly average was 0 µg/L and the highest single sample was 0 µg/L, from 36 samples taken from 2013 to 2019.

For HAA5, the average in the last year sampled was 0 µg/L. The worst yearly average was 0.5 µg/L and the highest single sample was 2.5 µg/L, from 36 samples.

A yearly average of 0 means nothing was detected in that year's samples. EPA's file stops at 2019; Ohio EPA's Drinking Water Watch has newer results.

Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, distribution-system samples (non-detects counted as zero).

Nitrate, arsenic and radioactivity

Nitrate was not detected in 8 samples through 2019 (limit 10 mg/L as nitrogen; above 10 is unsafe for infants).

Arsenic was not detected in 2 samples (limit 10 µg/L).

Measured in finished water: at the plant's entry points and in the distribution system; raw well and intake samples are left out. Non-detects count as zero.

Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, finished water.

Solvents and fuels

EPA's file holds results for all six solvent and fuel compounds it checked. Benzene, carbon tetrachloride, 1,2-dichloroethane, trichloroethylene, tetrachloroethylene, and vinyl chloride were not detected in 2 samples each.

"Not detected" means the lab's result was below what its method can measure, not that the compound is absent. Non-detects count as zero in the highest-result column.

Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, finished water.

Farm chemicals and metals

EPA's file holds results for 8 of the nine herbicides and metals it checked. Not detected: atrazine, alachlor, chromium, cadmium, barium, mercury, selenium, and thallium, in 2 samples each.

Non-detects count as zero in the highest-result column.

Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, finished water.

Bacteria in the pipes

From 2012 to 2019, 0 of 1,210 routine total coliform samples taken in the distribution system at St. Marys City tested positive (0%); in 2019, the last year on file, 0 of 138 did. E. coli was never found in the 1,210 samples tested for it.

A positive coliform test is a warning sign, not a violation by itself. E. coli is a sign that human or animal waste may have reached the water. Coliform counts are routine samples only; E. coli counts include repeat samples.

Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, distribution-system presence/absence tests for total coliform and E. coli.

Fluoride

The Ohio Department of Health's report to the CDC (My Water's Fluoride) says St. Marys City has fluoride from natural sources, but at a level below what is recommended for preventing tooth decay, and does not adjust it. The level it reports is 0.53 mg/L.

EPA's treatment table lists no fluoridation step at St. Marys City.

Measured fluoride: 0.37 mg/L on average at the plant's entry points in 2017 (below the 0.7 mg/L target); samples ran from 0.37 to 0.43 mg/L across 2 samples in 2012 to 2019.

The recommended level for preventing tooth decay is 0.7 mg/L; the federal limit is 4 mg/L. The treatment list is what each system registered with EPA and can lag a plant upgrade.

Source: CDC My Water's Fluoride (fluoridation status as reported by the Ohio Department of Health, fetched September 2026); EPA Safe Drinking Water Information System (SDWIS) treatment table; EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, entry-point fluoride samples.

Lithium

Lithium was found in 2 of 2 UCMR 5 samples at St. Marys City, highest 21.2 µg/L; detections averaged 21, last sampled in 2024.

Lithium is not regulated. EPA's draft health reference level is 10 µg/L, and it occurs naturally in deep groundwater, so well systems in the northwest run highest.

Source: EPA UCMR 5 occurrence data (final release, August 2026), samples from 2023 to 2025.

How well the service area is mapped

EPA estimated the service area of St. Marys City with a computer model rather than drawing it from the utility's map, so its edges are approximate.

Counting the people who live in the ZIP codes it overlaps, this atlas estimates 9,065 residents are inside the boundary, 97% of the 9,356 people St. Marys City reports serving.

The resident count is an estimate from 2020 Census ZIP-code populations, not a count of customers.

Source: EPA Service Area Boundaries; resident estimate by this atlas from ZIP-code overlap.