Water system
Monroe City
EPA ID OH0902012 · Butler County · 15,600 people served · owned by a local government
Monroe City buys its water from Butler Co. Water District 2.
The system's record
Also connected to Cincinnati Public Water System (Ohio River (Miller Plant, ~88%) plus Great Miami Buried Valley Aquifer wells (~12%)), used as a secondary or emergency supply.
- Aquifer
- Great Miami Buried Valley Aquifer
- Active wells
- 21
- Serves
- 62,447 people · Butler County
- EPA ID
- OH0904012
About this area's water
Did you know
- Monroe's tap water is a blend of two very different sources that meet before they reach the city: Ohio River surface water from Greater Cincinnati Water Works and Great Miami Buried Valley Aquifer groundwater from…
- Monroe holds emergency interconnections with the City of Middletown and with Warren County Water, and used no water from either during 2025.
- The Great Miami Buried Valley Aquifer is watched over by the Hamilton to New Baltimore Groundwater Consortium, which the county utility credits with an award-winning groundwater protection program.
- Greater Cincinnati Water Works' granular activated carbon treatment on Ohio River water lets it use substantially less chlorine than a conventional plant would need.
- A 29% wholesale increase from Butler County, which the city absorbed for a year before passing it on, pushed Monroe's inside-city water rate from $8.23 to $10.61 per 1,000 gallons on January 1, 2026.
History5
- 2020Radiological sampling at the City of Hamilton groundwater source behind Monroe's supply: alpha emitters at 2.8 pCi/L and radium-228 at 0.673 pCi/L, both well under their MCLs and still the current…
- 2023UCMR5 PFAS sampling at the Butler County interties finds PFBS at 3.3 ppt and PFHxS at 2.4 ppt (range ND-4.7) at the Hamilton Intertie-Liberty Fairfield; nothing detected at the Cincinnati…
- 2024Monroe more than doubles its stormwater fee on February 23, from $3.00 to $5.00 a month for residences, with commercial and industrial fees doubling at the same time, after concluding that rates set…
- 2025Monroe holds an unconditional Ohio EPA license to operate its water system; the city completes UCMR5 with every result below the minimum reporting level.
- 2026Monroe's inside-city water rate jumps from $8.23 to $10.61 per 1,000 gallons on January 1 - about 29% - after Butler County sharply raised the wholesale price it charges the city; Monroe had deferred…
Treatment & pressure
How it is treated
Monroe treats no water of its own. It buys finished water from Butler County Water & Sewer - Butler County Water District 2 - and distributes it. BCWS in turn buys surface water from the City of Cincinnati (Greater Cincinnati Water Works), drawn from the Ohio River and treated with granular…
Source: monroeohio.orgmonroeohio.org
Water pressure
Not published. Neither Monroe's 2025 CCR nor its water service, water quality or public works pages give a system pressure in psi, and no pressure-zone or storage description is…
What it costs
$10.61 per 1,000 gallons
Typical household bill about $50 a month for water.
Effective January 1, 2026, inside city limits: $10.61 per 1,000 gallons up to 20,000 gallons and $12.28 above 20,000 (up from $8.23 and $9.52 in 2025). Outside city limits: $17.50…
Source: monroeohio.orgmonroeohio.org
Water quality & impurities10
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| Total Trihalomethanes (City of Monroe… Range 6.90-47.1 ppb in Monroe's own distribution system; chlorination byproduct. The Butler County Water District 2… | 27.93 ppb | 80 | 2025 |
| Haloacetic Acids HAA5 (City of Monroe… Range 0-10.5 ppb. Butler County Water District 2 reported 9.425 ppb (range 0-9.5). | 7.73 ppb | 60 | 2025 |
| Lead, 90th percentile (City of Monroe… Zero of 31 samples over the action level. | 1.6 ppb | 15 (action… | 2025 |
| Copper, 90th percentile (City of Monroe… Zero of 31 samples over the action level - an unusually low copper 90th percentile. | 0.0181 ppm | 1.3 (action… | 2025 |
| Total Chlorine (City of Monroe PWS) Range 0.66-0.84 ppm. | 0.743 ppm | 4 (MRDL) | 2025 |
| Turbidity (Butler County Water District… Highest recorded result, range 0.04-0.16; 100% of samples met the turbidity limit. | 0.16 NTU | TT: <0.3 NTU in… | 2025 |
| Nitrate (Greater Cincinnati Water Works… Range 0.48-1.25 ppm. The City of Hamilton groundwater source measured 0.64 ppm (range ND-0.64). Both well below the… | 1.25 ppm | 10 | 2025 |
| Fluoride Greater Cincinnati Water Works 0.88 ppm (range 0.30-1.06); City of Hamilton 0.87 ppm (range 0.7-0.95). | 0.88 ppm | 4 | 2025 |
| Chlorine Dioxide (City of Hamilton… Range 100-660 ppb; disinfectant used on the Hamilton groundwater supply, and the highest reading relative to its limit… | 660 ppb | 800 (MRDL) | 2025 |
| Chlorite (City of Hamilton source) Range 0.41-0.70 ppm; byproduct of chlorine dioxide disinfection. | 0.68 ppm | 1.0 | 2025 |
Source: monroeohio.org
EPA compliance record
Lead at the tap: 90th-percentile result 1.6 ppb in 2025 (action level 15 ppb).
EPA record: no health-based violations since 2015.
6 violations of any kind logged since 2020: 4 for required testing that was missed or reported late; 2 for a report, record or notice that was missing, late or incomplete (the yearly water quality report, a public notice, lead line records).
EPA compliance record · Hamilton Public Water System (treats the water)
Lead at the tap: 90th-percentile result 2 ppb in 2024 (action level 15 ppb).
EPA record: no health-based violations since 2015.
2 violations of any kind logged since 2020: 1 for required testing that was missed or reported late; 1 for a report, record or notice that was missing, late or incomplete (the yearly water quality report, a public notice, lead line records).
Projects & plans4
Recent and current work
- Brittany Heights catch basin rehabilitation and N. Sands Ave. / Deneen Ave.-Britton Ln. storm pipe replacement · 2023 · completed
Three stormwater jobs let as a combined bid, replacing rusted corrugated metal pipe and rehabilitating catch basins. Monroe does not publish costs for its… - Old Street storm rehabilitation · 2022 · completed
New storm sewer, catch basins and 140 linear feet of 12-inch pipe, plus repair or replacement of 19 catch basins and cleaning and re-grading of 2,300 feet of… - Rosemont Park detention pond · 2021 · completed
Built in autumn 2021 specifically to address flooding issues. Delivered alongside a Lawton Avenue box culvert for stream capacity and ditch cleaning and… - Hamilton Lebanon Rd / Heritage Green Drive ditch realignment and Overbrook Drive / N. Main Street underdrain · 2020 · completed
Included about 900 feet of perforated pipe installation. No cost published.
Source: monroeohio.org
Supply stress
Both of Monroe's upstream sources are rated highly susceptible to contamination by Ohio EPA, for opposite reasons. The Great Miami Buried Valley Aquifer feeding Hamilton's North and South Wellfields is an unconfined sand and gravel aquifer with depth to water less than 30 feet, flat topography and very sandy soils that let a large share…
Source: monroeohio.orgmonroeohio.org
Sewers
Sanitary
Butler County Water & Sewer owns and maintains the sanitary sewer system serving Monroe and sets the sewer rates; the city bills customers, charging sewage on metered water use. Residential rates effective January 1, 2023 are $3.36 per 1,000 gallons where no lift station is involved and $3.70 per 1,000 gallons where one is, up from $3.27…
Storm
Unlike the sanitary system, the storm sewer is Monroe's own utility. The residential fee doubled from $3.00 to $5.00 a month effective February 23, 2024, with commercial and industrial fees - scaled by impervious surface area, starting at $10.00 a month for…
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
- 45050 · Monroe99% of residents
Also present in 2 more ZIP codes
- 45044 · Middletown6% of residents
- 45036 · Lebanon0% 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
Monroe City buys its water from Butler Co. Water District 2, which buys from Hamilton Public Water System.
No other system is on record buying water from Monroe City.
What the records show about Monroe City
Who runs it
EPA's record describes Monroe City as owned by a local government. It has 4,536 service connections and serves 15,600 people.
EPA classes it as a community water system, one that serves the same residents all year.
Its office telephone on EPA's record is 513-500-9181.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
Monroe City buys water that Hamilton Public Water System treats first, so the steps that count are the seller's. EPA's treatment table registers these steps for Hamilton Public Water System: aeration, chlorine dioxide, coagulation and settling, fluoridation, lime softening, and sand or media filtration.
Monroe City adds nothing of its own on that table.
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 Monroe City since 2015.
EPA logs 6 violations of any kind since 2020: 4 for required testing that was missed or reported late; 2 for a report, record or notice that was missing, late or incomplete (the yearly water quality report, a public notice, lead line records).
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 Monroe City was 1.6 ppb, under both the current 15 ppb action level and the 10 ppb level that applies from 2027.
The highest result on file is 7.5 ppb, in the period ending December 2019.
EPA has 9 sampling periods on file for Monroe City since 2016, the first ending in 2016; 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 Monroe City sent EPA, 4,582 lines are counted.
| Material | Lines |
|---|---|
| Lead | 0 |
| Galvanized, needing replacement | 2 |
| Unknown material | 2,170 |
| Not lead | 2,410 |
| All lines | 4,582 |
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 Monroe City in 2023 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 2 plants of Hamilton Public Water System (latest sample July 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 2 plants of Hamilton Public Water System as sampled, most recently February 2026.
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 Monroe City's samples in 2019, the last year it was sampled, was 26.7 µg/L. The worst yearly average was 26.7 µg/L and the highest single sample was 54.6 µg/L, from 84 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 4.2 µg/L. The worst yearly average was 5.6 µg/L and the highest single sample was 16.8 µg/L, from 82 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 26.7 µg/L (2019) | 26.7 µg/L | 54.6 µg/L | 84 |
| HAA5 | 60 µg/L | 4.2 µg/L | 5.6 µg/L | 16.8 µg/L | 82 |
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
The water Monroe City buys is treated by Hamilton Public Water System, so the results below are Hamilton Public Water System's.
Nitrate: the highest of 15 samples was 1.5 mg/L (as nitrogen), in 2019, the last year sampled. No sample was over the limit of 10 mg/L. Nitrate above 10 is unsafe for infants.
Arsenic was not detected in 4 samples (limit 10 µg/L).
| Contaminant | Samples | Highest result | Limit | Samples over limit |
|---|---|---|---|---|
| Nitrate (as nitrogen) | 15 | 1.5 mg/L | 10 mg/L | 0 |
| Arsenic | 4 | 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.
EPA's file lumps the entry-point samples of all 2 plants of Hamilton Public Water System together, so a result over a limit may come from a plant that serves a different part of town.
Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, finished water of Hamilton Public Water System.
Solvents and fuels
The water Monroe City buys is treated by Hamilton Public Water System, so the results below are Hamilton Public Water System's.
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 4 samples each.
| Compound | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|
| Benzene | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| Carbon tetrachloride | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| 1,2-dichloroethane | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| Trichloroethylene (TCE) | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| Tetrachloroethylene (PCE) | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| Vinyl chloride | 2 µg/L | 4 | 0 of 4 | 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 of Hamilton Public Water System.
Farm chemicals and metals
The water Monroe City buys is treated by Hamilton Public Water System, so the results below are Hamilton Public Water System's.
EPA's file holds results for 8 of the nine herbicides and metals it checked. Detected: barium in 2 of 4 samples, highest 57.2 µg/L (limit 2,000). Not detected: atrazine, alachlor, chromium, cadmium, mercury, selenium, and thallium, in 4 samples each.
| Substance | Kind | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|---|
| Atrazine | Farm chemical | 3 µg/L | 4 | 0 of 4 | not detected | 0 |
| Alachlor | Farm chemical | 2 µg/L | 4 | 0 of 4 | not detected | 0 |
| Chromium | Metal | 100 µg/L | 4 | 0 of 4 | not detected | 0 |
| Cadmium | Metal | 5 µg/L | 4 | 0 of 4 | not detected | 0 |
| Barium | Metal | 2,000 µg/L | 4 | 2 of 4 | 57.2 µg/L | 0 |
| Mercury | Metal | 2 µg/L | 4 | 0 of 4 | not detected | 0 |
| Selenium | Metal | 50 µg/L | 4 | 0 of 4 | not detected | 0 |
| Thallium | Metal | 2 µg/L | 4 | 0 of 4 | not detected | 0 |
Non-detects count as zero in the highest-result column.
EPA's file lumps the entry-point samples of all 2 plants of Hamilton Public Water System together, so a result over a limit may come from a plant that serves a different part of town.
Source: EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, finished water of Hamilton Public Water System.
Bacteria in the pipes
From 2012 to 2019, 10 of 1,187 routine total coliform samples taken in the distribution system at Monroe City tested positive (0.84%); in 2019, the last year on file, 1 of 120 did. E. coli was found in 4 of 1,025 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 Monroe City buys its water from Hamilton Public Water System, a system that adjusts the fluoride level to the recommended level for preventing tooth decay.
EPA's treatment table lists fluoridation among the steps at Hamilton Public Water System, which treats the water Monroe City buys.
Measured fluoride: 0.8 mg/L on average leaving the plants of Hamilton Public Water System, which supplies Monroe City, in 2018 (in the range dentists aim for); samples ran from 0.78 to 1.8 mg/L across 4 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 4 UCMR 5 samples at Monroe 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 Monroe City for a household using 5,000 gallons a month at $554 a year, about $46 a month.
| Use | Water, per year | Sewer, per year |
|---|---|---|
| 2,500 gallons a month | $330 | not on file |
| 5,000 gallons a month | $554 | not on file |
| 8,000 gallons a month | $823 | not on file |
The survey lists it as “Monroe”. 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
EPA estimated the service area of Monroe 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 15,487 residents are inside the boundary, 99% of the 15,600 people Monroe 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 — 3 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 OH0902012 (EPA ECHO).
Monroe City's own pages: journal-news.com, ewg.org
Notable facts: monroeohio.org, monroeohio.org, monroeohio.org, monroeohio.org
History: monroeohio.org, monroeohio.org, monroeohio.org
Water quality: monroeohio.org
Planned work: monroeohio.org, monroeohio.org
Water pressure: monroeohio.org, monroeohio.org, monroeohio.org
Capital projects: monroeohio.org
Rates: monroeohio.org, monroeohio.org
Sewers: monroeohio.org, monroeohio.org, monroeohio.org
Treatment: monroeohio.org, monroeohio.org
Supply stress: monroeohio.org, monroeohio.org
