Water system
Aqua Ohio - Tiffin
EPA ID OH7400614 · Seneca County · 20,279 people served
Aqua Ohio - Tiffin treats its own water from Sandusky River.
The system's record
- Water bodies
- Sandusky River
- Raw intakes
- Sandusky River
- Active wells
- 5
- Serves
- 20,279 people · Seneca County
- EPA ID
- OH7400614
About this area's water
Did you know
- Tiffin is one of the few Ohio cities of its size whose tap water comes from an investor-owned utility: Aqua Ohio bought the system from Ohio American Water in May 2012, so water rates are set by the Public Utilities…
- Aqua Ohio's report states plainly that the company does not hold regular public meetings on drinking water quality - customers with concerns are pointed to a call center, the PUCO, or the Ohio Consumers' Counsel.
- Individual trihalomethane samples in 2025 reached 101.2 ppb, above the 80 ppb standard, even though the running average that determines compliance came in at 70.2 ppb.
- The Sandusky River both supplies Tiffin's intake and receives the city's combined sewer overflows - the wastewater plant's $27 million high-rate filtration project is aimed at cutting those overflows to four a year by…
- In a rate case where a 'Seneca' service area appears on the state consumer advocate's chart, that line is Lake Seneca in Williams County, not Tiffin in Seneca County; Tiffin bills under the former Ohio American Water…
History6
- 1913The Great Flood of 1913 on the Sandusky River devastated Tiffin - the same river that supplies the city's drinking water intake.
- 2003Ohio EPA completed the source water assessment for the Tiffin system; the source is rated highly susceptible to contamination, with the single rating driven by the surface water intake rather than…
- 2012Aqua Ohio purchased the Tiffin water system from Ohio American Water in May 2012, as part of Aqua America's acquisition of all of American Water's regulated Ohio operations (about 50,730 water…
- 2023Aqua replaced 90-year-old cast iron mains on Grand Avenue, Fifth Avenue and Huss Street with ductile iron - a $1,324,000 contract, part of roughly $3.1 million invested in Tiffin that year.
- 2025Aqua Ohio filed PUCO case 25-0594-WW-AIR (June 30, 2025) seeking $13.4 million, or 16.4%, more annual water revenue across its rate-regulated Ohio systems.
- 2026PUCO issued its order June 10, 2026, authorizing about $9.5 million rather than the $13.4 million requested and rejecting Aqua's proposed increase to the fixed monthly customer charge; the resulting…
Treatment & pressure
How it is treated
Aqua Ohio treats Sandusky River water at its Tiffin plant, with five groundwater wells supplementing or backing up the river supply. The 2025 CCR documents conventional surface-water treatment: filtration monitored by turbidity (limit 0.3 NTU in 95% of daily samples; Tiffin's highest 2025 reading…
What it costs
$15.67 per 1,000 gallons
Typical household bill about $77 a month for water.
Tiffin falls in Aqua Ohio's PUCO Tariff No. 2 Rate Group 3 (systems formerly served by Ohio American Water, which Aqua bought in May 2012). Effective July 22, 2026 under the…
Water quality & impurities10
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| Total Trihalomethanes (TTHM) Range of individual detections 20.2-101.2 ppb - individual samples exceeded the MCL value even though the compliance… | 70.2 ppb | 80 ppb MCL | 2025 |
| Haloacetic Acids (HAA5) Range 18.6-51.2 ppb. | 36.4 ppb | 60 ppb MCL | 2025 |
| Nitrate Range 0.14-6.8 ppm; the CCR carries the infant blue-baby-syndrome advisory and warns that levels can rise quickly after… | 6.8 ppm | 10 ppm MCL | 2025 |
| Atrazine Range ND-0.3 ppb; row-crop herbicide runoff. | 0.3 ppb | 3 ppb MCL | 2025 |
| Barium Erosion of natural deposits. | 0.05 ppm | 2 ppm MCL | 2025 |
| Fluoride Range 0.8-1.0 ppm. | 0.9 ppm | 4 ppm MCL | 2025 |
| Total Chlorine Range 1.1-1.3 ppm. | 1.3 ppm | 4 ppm MRDL | 2025 |
| Turbidity Range 0.02-0.15 NTU; 100% of samples met the standard. | 0.15 NTU | Treatment… | 2025 |
| Lead (90th percentile) 0 of 30 samples over the action level. | 5.4 ppb | 15 ppb action… | 2025 |
| Copper (90th percentile) 1 of 30 samples exceeded the action level, at 1.4 ppm; the 90th percentile stayed well below it. | 0.16 ppm | 1.3 ppm action… | 2025 |
Source: prod.aquawater.com
EPA compliance record
Lead at the tap: 90th-percentile result 5.4 ppb in 2025 (action level 15 ppb).
EPA record: no health-based violations since 2015.
Projects & plans4
Recent and current work
- Grand Avenue / Fifth Avenue / Huss Street water main replacement · $1.3 million · 2023 · completed
Replaced 90-year-old 6- and 10-inch cast iron with 2,550 feet of 8- and 12-inch ductile iron on Grand Ave, a 12-inch on Fifth Ave, and 2,355 feet of 12-inch on… - Tiffin Water Pollution Control Center capacity upgrade (city project, not Aqua) · 2021 · completed
Raised treatable flow from 4 MGD to 13 MGD with a new 80-foot secondary clarifier and a 13-million-gallon equalization basin, under the 2017 long-term control…
Source: tiffinohio.govtiffinohio.gov
Planned or needed
- AquaStorm high-rate cloth-media filtration at the city's Water Pollution Control Center · $27 million · 2026-2028 · planned
Bid awarded to Adena; construction expected to start within months of the mid-2026 council briefing and the system online by July 2028. Treats up to 32 MGD… - Ongoing Aqua Ohio system investment · 2026 · planned
Aqua's 2025 CCR states the company invested nearly $559 million in Ohio water systems from 2015-2025 and plans roughly $61 million statewide in 2026; no…
Source: tiffinohio.netprod.aquawater.com
Supply stress
A single river intake on the Sandusky, backed by five wells, in an agricultural watershed that Ohio EPA rates highly susceptible to contamination - the listed threats include agricultural runoff, construction runoff, oil and gas production, unsewered areas, wastewater discharges, landfills and commercial sources. The pressure shows up in…
Source: prod.aquawater.comtiffinohio.gov
Sewers
Sanitary
Sanitary sewer and treatment are run by the City of Tiffin's Water Pollution Control Center at 961 N. Water St. - a separate utility from Aqua's water system. Tiffin discharged raw sewage to the Sandusky River until a primary plant was built in 1955; secondary treatment and sludge filtration followed in 1964, a third digester and…
Storm
Tiffin has a combined sewer system: stormwater and sanitary flow share pipes, and overflows discharge to the Sandusky River. The long-term control plan targets no more than four combined sewer overflow activations per year, and the city publishes an annual…
Source: tiffinohio.govtiffinohio.net
Sourcesverified
Compiled from the utility's own reports and public records, then independently re-checked against primary sources.
Main supplier in 1 ZIP code
Serves
Main water supplier in 1 ZIP code
- 44883 · Tiffin64% of residents
Population-weighted resident shares; a ZIP code can have more than one system on record. Recomputed from each ZIP's own system list, not from the map's cached footprint.
Buys from · Sells to
Aqua Ohio - Tiffin does not buy water from another system on record; it treats its own source water.
No other system is on record buying water from Aqua Ohio - Tiffin.
What the records show about Aqua Ohio - Tiffin
Who runs it
EPA's record says Aqua Ohio - Tiffin has 8,311 service connections and serves 20,279 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 2018. Its office telephone on EPA's record is 740-383-0939.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
EPA's treatment table registers these steps for Aqua Ohio - Tiffin: aeration, corrosion control, coagulation and settling, chlorine disinfection, fluoridation, granular activated carbon, and powdered activated carbon.
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's record shows no health-based violations for Aqua Ohio - Tiffin since 2015.
EPA logs no violations of any kind for Aqua Ohio - Tiffin since 2020.
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 Aqua Ohio - Tiffin was 5.4 ppb, under both the current 15 ppb action level and the 10 ppb level that applies from 2027.
The highest result on file is 13 ppb, in the period ending December 2020.
EPA has 9 sampling periods on file for Aqua Ohio - Tiffin since 2016, the first ending in 2016; 1 of the 9 periods went above 10 ppb.
Every water system has to inventory its service lines, the pipes from the main to each building. In the inventory Aqua Ohio - Tiffin sent EPA, 8,525 lines are counted.
| Material | Lines |
|---|---|
| Lead | 2,012 |
| Galvanized, needing replacement | 152 |
| Unknown material | 4,065 |
| Not lead | 2,296 |
| All lines | 8,525 |
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 4 samples of the water entering the pipes of Aqua Ohio - Tiffin in 2023 to 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 Aqua Ohio - Tiffin (latest sample September 2020). Not one of the six PFAS tested (PFOA, PFOS, PFHxS, PFNA, GenX and PFBS) was detected.
Ohio EPA's current sampling status map lists 1 plant of Aqua Ohio - Tiffin as sampled, most recently July 2024.
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 Aqua Ohio - Tiffin's samples in 2019, the last year it was sampled, was 60.6 µg/L. The worst yearly average was 60.6 µg/L and the highest single sample was 97.6 µg/L, from 132 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 34.2 µg/L. The worst yearly average was 35.2 µg/L and the highest single sample was 76.8 µg/L, from 132 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 60.6 µg/L (2019) | 60.6 µg/L | 97.6 µg/L | 132 |
| HAA5 | 60 µg/L | 34.2 µg/L | 35.2 µg/L | 76.8 µg/L | 132 |
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: the highest of 113 samples was 11.1 mg/L (as nitrogen) in 2014; in 2019, the last year sampled, the highest was 4.42 mg/L. 1 of the samples went over the limit of 10 mg/L. Nitrate above 10 is unsafe for infants.
Arsenic was not detected in 8 samples (limit 10 µg/L).
| Contaminant | Samples | Highest result | Limit | Samples over limit |
|---|---|---|---|---|
| Nitrate (as nitrogen) | 113 | 11.1 mg/L | 10 mg/L | 1 |
| Arsenic | 8 | not detected | 10 µg/L | 0 |
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 8 samples each.
| Compound | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|
| Benzene | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| Carbon tetrachloride | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| 1,2-dichloroethane | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| Trichloroethylene (TCE) | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| Tetrachloroethylene (PCE) | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| Vinyl chloride | 2 µg/L | 8 | 0 of 8 | not detected | 0 |
"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 all nine herbicides and metals it checked. Detected: atrazine in 24 of 34 samples, highest 5.3 µg/L (limit 3, 2 over); cadmium in 1 of 8 samples, highest 0.8 µg/L (limit 5); barium in 7 of 8 samples, highest 70.5 µg/L (limit 2,000). Not detected: alachlor in 34 samples, 2,4-D in 3 samples, chromium in 8 samples, mercury in 8 samples, selenium in 8 samples, thallium in 8 samples.
| Substance | Kind | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|---|
| Atrazine | Farm chemical | 3 µg/L | 34 | 24 of 34 | 5.3 µg/L | 2 |
| Alachlor | Farm chemical | 2 µg/L | 34 | 0 of 34 | not detected | 0 |
| 2,4-D | Farm chemical | 70 µg/L | 3 | 0 of 3 | not detected | 0 |
| Chromium | Metal | 100 µg/L | 8 | 0 of 8 | not detected | 0 |
| Cadmium | Metal | 5 µg/L | 8 | 1 of 8 | 0.8 µg/L | 0 |
| Barium | Metal | 2,000 µg/L | 8 | 7 of 8 | 70.5 µg/L | 0 |
| Mercury | Metal | 2 µg/L | 8 | 0 of 8 | not detected | 0 |
| Selenium | Metal | 50 µg/L | 8 | 0 of 8 | not detected | 0 |
| Thallium | Metal | 2 µg/L | 8 | 0 of 8 | not detected | 0 |
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, 2 of 2,024 routine total coliform samples taken in the distribution system at Aqua Ohio - Tiffin tested positive (0.1%); in 2019, the last year on file, 1 of 253 did. E. coli was never found in the 2 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 Aqua Ohio - Tiffin adjusts the fluoride level to the recommended level for preventing tooth decay.
EPA's treatment table lists fluoridation among the steps at Aqua Ohio - Tiffin.
Measured fluoride: 0.89 mg/L on average at the plant's entry points in 2019 (in the range dentists aim for); samples ran from 0.87 to 1.01 mg/L across 8 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 4 UCMR 5 samples at Aqua Ohio - Tiffin, highest 14.7 µg/L; detections averaged 12.6, 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.
Algal toxins
Ohio EPA tests for microcystin, a toxin that harmful algal blooms can release, in raw water at the intake and in treated water.
No microcystin was detected in the 200 raw-water samples.
Microcystin was never detected in treated water (78 samples).
In all, 278 samples from 2016 to 2026, the latest on August 25, 2026.
| Water | Samples | Detections | Highest result |
|---|---|---|---|
| Raw water, at the intake | 200 | 0 | not detected |
| Treated water | 78 | 0 | not detected |
The ten-day advisory levels for treated water are 0.3 µg/L for children under six and 1.6 µg/L for everyone else. Any detection at the intake triggers more frequent testing until two clean weeks.
Source: Ohio EPA public water system harmful algal bloom monitoring, 2016 to present (HAB data, fetched September 2026).
How well the service area is mapped
The service area drawn on the map for Aqua Ohio - Tiffin comes from the utility's own map.
Counting the people who live in the ZIP codes it overlaps, this atlas estimates 18,324 residents are inside the boundary, 90% of the 20,279 people Aqua Ohio - Tiffin 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.
Photograph
On the map
Show this system's territory on the map — 1 ZIP code in all.
Sources
U.S. EPA SDWIS and Community Water System Service Area Boundaries (v3, 2026), Ohio EPA primacy data, 2020 census blocks: the system serving most residents, traced through purchases to the treating utility; Ohio EPA 2023 Sewer and Water Rate Survey (Ohio State, May 2025) for household bills; Ohio EPA DEFA loan awards since 2016 for the loans paragraph · EPA SDWIS · EPA service area boundaries · Ohio EPA drinking water · Ohio EPA rate survey
EPA's own record for this system: Enforcement and Compliance History report for OH7400614 (EPA ECHO).
Aqua Ohio - Tiffin's own pages: aquawater.com
Notable facts: prod.aquawater.com, essential.co, occ.ohio.gov, tiffinohio.net
History: prod.aquawater.com, essential.co, tiffinohio.gov, occ.ohio.gov
Water quality: prod.aquawater.com
Planned work: tiffinohio.net, prod.aquawater.com
Capital projects: tiffinohio.gov, tiffinohio.gov
Rates: dam.assets.ohio.gov, occ.ohio.gov, puco.ohio.gov
Sewers: tiffinohio.gov, tiffinohio.net
Treatment: prod.aquawater.com, prod.aquawater.com
Supply stress: prod.aquawater.com, tiffinohio.gov
