Water system
Fairfield City
EPA ID OH0900715 · Butler County · 44,907 people served · owned by a local government
Fairfield City treats its own water from Great Miami Buried Valley Aquifer (wells).
The system's record
- Aquifer
- Great Miami Buried Valley Aquifer
- Active wells
- 6
- Serves
- 44,907 people · Butler County
- EPA ID
- OH0900715
About this area's water
Did you know
- The plant pumped and treated over 2 billion gallons in 2025 from just six deep wells tapping sand and gravel that glaciers laid down more than 10,000 years ago.
- Lead is barely an issue here: the city reports no known lead water service lines or mains, and the 2025 90th-percentile result was 2.4 ppb against a 15 ppb action level.
- Fairfield keeps emergency interconnections with Butler County, Cincinnati and Hamilton, and used the Butler County one in 2025 for 1,518,554 gallons.
- The plant's original 1956 ion-exchange softening was retired as two-stage lime softening phased in between 1983 and 2000, lifting lime capacity to 9.1 MGD.
History5
- 1956Original water treatment plant built on Groh Lane with 750,000 gallons-per-day capacity.
- 1963Plant doubled in size, raising production to 1.5 MGD.
- 1983First lime-softening phase added: two solid-contact clarifiers of 2.5 MGD each.
- 1998-2000Second lime-softening phase adds two more 2.5 MGD clarifiers, lime-plant capacity reaches 9.1 MGD, and the ion-exchange train is dismantled.
- 2025City activates an emergency interconnection with Butler County, flowing 1,518,554 gallons into the Fairfield system.
Treatment & pressure
How it is treated
Six deep wells draw the Great Miami Buried Valley Aquifer; water is aerated to strip CO2, lime-softened in solid-contact clarifiers, pH-adjusted by recarbonation, disinfected with sodium hypochlorite, filtered, fluoridated, and held in a clear well.
Water pressure
Not published. No psi figure or zone map found; the city describes about 200 miles of main with storage towers, pump stations and pressure regulators.
What it costs
$5.41 per 1,000 gallons
3/4-inch meter: $17.70/month minimum covers 3,000 gal, then $5.41/1,000 gal. Sewer is $20.67 plus $6.89/1,000 gal; trash $16.13/month.
Water quality & impurities8
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| TTHM (total trihalomethanes) Range 25.0-27.9 ppb, about a third of the limit. | 27.9 ppb | 80 | 2025 |
| HAA5 (haloacetic acids) Range 2.4-3.8 ppb; very low for a chlorinated supply. | 3.8 ppb | 60 | 2025 |
| Lead (90th percentile) 60 homes sampled; 2 individual results over the AL, 90th percentile well under it. | 2.4 ppb | 15 (action… | 2025 |
| Copper (90th percentile) Zero of 60 samples over the action level. | 0.024 ppm | 1.3 (action… | 2025 |
| Nitrate Well under the MCL; background nitrate is one marker of aquifer vulnerability. | 1.28 ppm | 10 | 2025 |
| Fluoride Added to promote strong teeth; range 0.65-1.14 ppm. | 1.14 ppm | 4 | 2025 |
| HFPO-DA (GenX) UCMR5 detection; PFOA and PFOS both under 4 ppt, below the reporting limit. | 5.7 ppt | 10 (EPA MCL) | 2023-202… |
| Nickel Unregulated, no MCL; sits just under EPA's lifetime health advisory level. | 0.091 ppm | 0.1 (lifetime… | 2023 |
EPA compliance record
Lead at the tap: 90th-percentile result 0 ppb in 2026 (action level 15 ppb).
EPA record: no health-based violations since 2015.
Supply stress
Sole source is the Great Miami Buried Valley Aquifer, which Ohio EPA calls highly susceptible: no protective clay cap, shallow water, nearby contaminant sources, low background nitrate. Fairfield activated an emergency Butler County interconnection in 2025, importing 1.5 million gallons.
Sewers
Sanitary
The City of Fairfield provides wastewater service as well as water; sewer is billed at a $20.67 monthly minimum for 3,000 gal plus $6.89/1,000 gal. We found no published plant name, capacity, receiving stream, CSO status or consent decree.
Storm
No separate stormwater utility fee appears on the city's utility rate schedule, which lists only water, sewer and trash charges.
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
- 45014 · Fairfield88% of residents
Also present in 1 more ZIP code
- 45011 · Liberty Township and Hamilton1% 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
Fairfield City does not buy water from another system on record; it treats its own source water.
No other system is on record buying water from Fairfield City.
What the records show about Fairfield City
Who runs it
EPA's record describes Fairfield City as owned by a local government. It has 13,682 service connections and serves 44,907 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 513-858-8348.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
EPA's treatment table registers these steps for Fairfield City: aeration, corrosion control, coagulation and settling, chlorine disinfection, fluoridation, 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's record shows no health-based violations for Fairfield City since 2015.
EPA logs no violations of any kind for Fairfield City 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 June 2026, the 90th-percentile lead result at Fairfield 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 2.4 ppb, in the period ending December 2025.
EPA has 9 sampling periods on file for Fairfield City since 2016, the first ending in 2018; 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 Fairfield City sent EPA, 13,497 lines are counted.
| Material | Lines |
|---|---|
| Lead | 0 |
| Galvanized, needing replacement | 0 |
| Unknown material | 0 |
| Not lead | 13,497 |
| All lines | 13,497 |
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 Fairfield City in 2023 to 2024 and measured 29 PFAS.
PFOA and PFOS were not detected, against a federal limit of 4 ng/L each.
The highest PFAS results were PFBA 5.7 ng/L, HFPO-DA 5.7 ng/L, and PFPeA 4.3 ng/L.
The system reported potential PFAS sources near its supply.
Ohio EPA's own statewide sampling tested 1 plant of Fairfield City (latest sample June 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 Fairfield City as sampled, most recently March 2026.
| Compound | Highest result | Federal limit |
|---|---|---|
| PFOA | not detected | 4 ng/L |
| PFOS | not detected | 4 ng/L |
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 Fairfield City's samples in 2019, the last year it was sampled, was 33.3 µg/L. The worst yearly average was 33.3 µg/L and the highest single sample was 38.4 µg/L, from 37 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 5 µg/L. The worst yearly average was 6.4 µg/L and the highest single sample was 10.1 µg/L, from 37 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 33.3 µg/L (2019) | 33.3 µg/L | 38.4 µg/L | 37 |
| HAA5 | 60 µg/L | 5 µg/L | 6.4 µg/L | 10.1 µg/L | 37 |
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 8 samples was 3.19 mg/L (as nitrogen) in 2015; in 2019, the last year sampled, the highest was 1.83 mg/L. No sample was over the limit of 10 mg/L. Nitrate above 10 is unsafe for infants.
Arsenic was not detected in 2 samples (limit 10 µg/L).
| Contaminant | Samples | Highest result | Limit | Samples over limit |
|---|---|---|---|---|
| Nitrate (as nitrogen) | 8 | 3.19 mg/L | 10 mg/L | 0 |
| Arsenic | 2 | 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 2 samples each.
| Compound | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|
| Benzene | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| Carbon tetrachloride | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| 1,2-dichloroethane | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| Trichloroethylene (TCE) | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| Tetrachloroethylene (PCE) | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| Vinyl chloride | 2 µg/L | 2 | 0 of 2 | 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: barium in 2 of 2 samples, highest 33 µg/L (limit 2,000). Not detected: atrazine, alachlor, 2,4-D, chromium, cadmium, mercury, selenium, and thallium, in 2 samples each.
| Substance | Kind | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|---|
| Atrazine | Farm chemical | 3 µg/L | 2 | 0 of 2 | not detected | 0 |
| Alachlor | Farm chemical | 2 µg/L | 2 | 0 of 2 | not detected | 0 |
| 2,4-D | Farm chemical | 70 µg/L | 2 | 0 of 2 | not detected | 0 |
| Chromium | Metal | 100 µg/L | 2 | 0 of 2 | not detected | 0 |
| Cadmium | Metal | 5 µg/L | 2 | 0 of 2 | not detected | 0 |
| Barium | Metal | 2,000 µg/L | 2 | 2 of 2 | 33 µg/L | 0 |
| Mercury | Metal | 2 µg/L | 2 | 0 of 2 | not detected | 0 |
| Selenium | Metal | 50 µg/L | 2 | 0 of 2 | not detected | 0 |
| Thallium | Metal | 2 µg/L | 2 | 0 of 2 | 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 4,800 routine total coliform samples taken in the distribution system at Fairfield City tested positive (0.04%); in 2019, the last year on file, 0 of 600 did. E. coli was never found in the 6 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 Fairfield City adjusts the fluoride level to the recommended level for preventing tooth decay.
EPA's treatment table lists fluoridation among the steps at Fairfield City.
Measured fluoride: 0.97 mg/L on average at the plant's entry points in 2017 (in the range dentists aim for); samples ran from 0.97 to 1.03 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 not detected in 2 UCMR 5 samples at Fairfield City, last sampled in 2023 (the method reports from 9 µg/L).
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.
Water and sewer bills
Ohio EPA's 2023 rate survey puts the water bill at Fairfield City for a household using 5,000 gallons a month at $315 a year, about $26 a month.
The sewer bill in the same survey is $374 a year at 5,000 gallons a month.
| Use | Water, per year | Sewer, per year |
|---|---|---|
| 2,500 gallons a month | $195 | $225 |
| 5,000 gallons a month | $315 | $374 |
| 8,000 gallons a month | $494 | $599 |
The survey lists it as “Fairfield”. These are inside-city rates and annual bills at the use shown.
Source: Ohio EPA 2023 Sewer and Water Rate Survey (Ohio State University, May 2025).
How well the service area is mapped
The service area drawn on the map for Fairfield City comes from the utility's own map.
Counting the people who live in the ZIP codes it overlaps, this atlas estimates 41,189 residents are inside the boundary, 92% of the 44,907 people Fairfield 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.
On the map
Show this system's territory on the map — 2 ZIP codes 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 OH0900715 (EPA ECHO).
Fairfield City's own pages: fairfield-city.org, data.epa.gov, hamilton-oh.gov
