Water system
Wilmington City
EPA ID OH1401211 · Clinton County · 12,401 people served · owned by a local government
Wilmington City treats its own water from Caesar Creek Lake (with Burtonville reservoirs/Cowan Creek as backup).
The system's record
- Water bodies
- Caesar Creek Lake, Burtonville Reservoirs (Cowan Creek)
- Raw intakes
- Wilmington Caesar Lake Inta
Wilmington Reservoir
Wilmington Cowan Creek Inta - Serves
- 12,401 people · Clinton County
- EPA ID
- OH1401211
About this area's water
Did you know
- Wilmington's backup reservoirs became the contaminated ones: the Burtonville pair, built in 1945 and 1962 as the city's safety net, hold PFOS and PFHxS from firefighting foam the military required at the adjacent Wilmington Air Park, while the 'distant' Army Corps lake 14 miles away is the clean primary source.
- The city sued 3M, maker of the PFAS-containing firefighting foam, in federal court to recover contamination costs.
- Caesar Creek Lake, the primary source, is a 2,830-acre Army Corps flood-control reservoir with 40 miles of shoreline draining a 237-square-mile watershed.
- Wilmington's water was privately owned for roughly half a century: Dayton Power and Light ran the water and electric utility from 1914 until the city took the water system back around 1970.
- The city keeps an auxiliary interconnection with the Western Water Company purely to keep outlying customers in water during main-break repairs.
History6
- 1899-1906After a mixed 1899 vote and a successful 1901 vote, Wilmington's first municipal water system was completed in 1906.
- 1914Dayton Power and Light took over the local water and electric utility.
- 1945First Burtonville reservoir (100 million gallons) built, along with a water plant on Wall Street that operated until 2000.
- 1962Second Burtonville reservoir added (350 million gallons), giving 450 million gallons of combined backup storage.
- 1970The City took over the water system from Dayton Power and Light (city states 'around 1970').
- 1990Current water treatment plant built.
Treatment & pressure
How it is treated
Surface-water lime softening plant. Multi-stage: powdered activated carbon adsorption, coagulation/flocculation with aluminum sulfate and lime, softening, sedimentation, re-carbonation, filtration through eight coal-and-sand filters, stabilization, and chlorine disinfection. The plant produces about 2 million gallons per day and is designed for up to 4 MGD, serving roughly 12,500 people.
Source: wilmingtonohio.govgemgrp.com
Water pressure
The only distribution figures published are four water towers plus two clearwells totaling 3.25 million gallons of storage.
Source: wilmingtonohio.govgemgrp.com
What it costs
$10.03 per 1,000 gallons
Typical household bill about $47 a month for water.
Codified in Wilmington Code of Ordinances Sec. 929.01 (Ord. O-25-61, sec. 1, adopted 11-6-25; code version June 12, 2026). Inside-city usage fee is tiered per 1,000 gallons: $10.03 for 0-50, $9.02 for 50-200, $8.08 for 200+ (tiers in thousands of gallons).
Water quality & impurities10
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| Total trihalomethanes (TTHM) Range of individual detections 23.5-83.9 ppb; the high end exceeds the 80 ppb MCL although compliance is judged on the locational running annual average, which the CCR reports as meeting the standard. | 63.3 ppb | 80 (LRAA) | 2025 |
| Haloacetic acids (HAA5) Range 13.8-23.0 ppb. By-product of chlorinating organic-rich reservoir water. | 22.1 ppb | 60 (LRAA) | 2025 |
| Total organic carbon (TOC) Range 2.76-4.33 ppm; TOC is the disinfection-byproduct precursor and explains the high TTHM. | 3.61 ppm | treatment technique | 2025 |
| Chlorine Range 1.32-2.66 ppm. | 2.18 ppm | 4 (MRDL) | 2025 |
| Nitrate Range 0.46-3.24 ppm; agricultural watershed. | 3.24 ppm | 10 | 2025 |
| Fluoride Range 0.80-1.07 ppm; added at the plant. | 0.93 ppm | 4 | 2025 |
| Barium Far below the MCL. | 0.0085 ppm | 2 | 2025 |
| Cyanide Far below the MCL. | 1.56 ppb | 200 | 2025 |
| Turbidity 100% of monthly samples met the limit. | 0.14 NTU | treatment technique | 2025 |
| Lead Range ND-4.8 ppb; 0 of 30 samples over the action level. | 0.8 (90th percentile) ppb | 15 (action level) | 2025 |
Source: gemgrp.comwilmingtonohio.gov
EPA compliance record
Lead at the tap: 90th-percentile result 0.8 ppb in 2025 (action level 15 ppb).
EPA record: no health-based violations since 2015.
1 violation of any kind logged since 2020: 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 & plans3
Recent and current work
- New Wilmington wastewater treatment plant · $5 million · 2023-2026 · under construction
Being built on S. Nelson Avenue across from the existing plant at 475 S. Nelson Ave. Average daily capacity will be 50% higher than the existing plant and it will handle up to 125% more wet-weather flow, to meet tightening limits for discharge to Lytle Creek. - Water tower upgrades · 2015 · completed
City states its water has met every state and federal standard since upgrades were installed in two water towers in 2015.
Source: wilmingtonohio.govwilmingtonohio.govwnewsj.com
Planned or needed
- PFAS removal feasibility study for the Burtonville reservoirs · planned
City states it secured federal funding for a study to determine how PFAS could be removed so the reservoirs can be used in the future.
Source: wilmingtonohio.gov
Supply stress
Wilmington's stress is quality, not quantity. Its backup reservoirs at Burtonville carry PFOS and PFHxS at roughly 10-20 ppt from firefighting foam the military mandated at the adjacent Wilmington Air Park; the city sued 3M and is pursuing a PFAS-removal study. The reservoirs have not been abandoned - the 2025 CCR says they are 'often used when the water from Caesar Creek Lake is of poor quality,' which happens when the Army Corps lake blooms (a 2017 harmful algal bloom forced a switch).
Sewers
Sanitary
City-operated. The existing Wilmington Wastewater Treatment Plant is at 475 S. Nelson Ave.; treated effluent discharges to Lytle Creek and biosolids are land-applied to agricultural fields for their fertilizer value. A replacement plant has been under construction since 2023 on the opposite side of S. Nelson Ave., with 50% more average daily capacity and up to 125% more wet-weather capacity; a $5 million state grant was awarded toward the work.
Storm
Wilmington runs a genuine stormwater utility (Code Ch. 924, with illicit-discharge and comprehensive stormwater management under Ch. 938 and 939). The residential charge is $0.0271 per square foot of impervious surface per year, billed monthly.
Source: wilmingtonohio.govwilmingtonohio.govwilmingtonohio.gov
Serves
Main water supplier in 1 ZIP code
- 45177 · Wilmington61% 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
Wilmington 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 Wilmington City.
What the records show about Wilmington City
Who runs it
EPA's record describes Wilmington City as owned by a local government. It has 5,198 service connections and serves 12,401 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 2020. Its office telephone on EPA's record is 937-382-3614.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
EPA's treatment table registers these steps for Wilmington City: corrosion control, coagulation and settling, chlorine disinfection, iron and manganese removal, fluoridation, lime softening, powdered activated carbon, 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 Wilmington City since 2015.
EPA logs 1 violation of any kind since 2020: 1 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 November 2026).
Lead and copper at the tap
In the sampling period ending December 2025, the 90th-percentile lead result at Wilmington City was 0.8 ppb, under both the current 15 ppb action level and the 10 ppb level that applies from 2027.
EPA has 4 sampling periods on file for Wilmington 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 Wilmington City sent EPA, 5,143 lines are counted.
| Material | Lines |
|---|---|
| Lead | 161 |
| Galvanized, needing replacement | 292 |
| Unknown material | 2,822 |
| Not lead | 1,868 |
| All lines | 5,143 |
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 5 samples of the water entering the pipes of Wilmington City in 2023 and measured 29 PFAS.
The highest PFOA or PFOS result, 7.3 ng/L, is at or above the federal limit of 4 ng/L that EPA set in 2024. Systems have until 2029 to comply, and in May 2026 EPA proposed letting systems apply for two more years. One sample over the limit is not a violation: compliance is judged on a running annual average.
The highest PFAS results were PFPeA 9.8 ng/L, PFHxA 8.2 ng/L, and PFOS 7.3 ng/L.
The system reported potential PFAS sources near its supply.
Ohio EPA's own statewide sampling tested 1 plant of Wilmington City (latest sample May 2021). The highest result was PFOS at 14.4 ppt (ppt is the same unit as ng/L), against Ohio's action level of 70 ppt. Those action levels are the ones Ohio EPA used for the survey; the 2024 federal limit for PFOA and PFOS is 4 ng/L.
Ohio EPA's current sampling status map lists 1 plant of Wilmington City as sampled, most recently November 2023.
| Compound | Highest result | Federal limit |
|---|---|---|
| PFOA | not detected | 4 ng/L |
| PFOS | 7.3 ng/L | 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 Wilmington City's samples in 2019, the last year it was sampled, was 44.2 µg/L. The worst yearly average was 67.5 µg/L and the highest single sample was 106 µg/L, from 129 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 22.5 µg/L. The worst yearly average was 26.9 µg/L and the highest single sample was 43.9 µg/L, from 129 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 44.2 µg/L (2019) | 67.5 µg/L | 106 µg/L | 129 |
| HAA5 | 60 µg/L | 22.5 µg/L | 26.9 µg/L | 43.9 µg/L | 129 |
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 96 samples was 3.8 mg/L (as nitrogen) in 2013; in 2019, the last year sampled, the highest was 2.56 mg/L. No sample was 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) | 96 | 3.8 mg/L | 10 mg/L | 0 |
| 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 8 of the nine herbicides and metals it checked. Detected: atrazine in 5 of 22 samples, highest 1.1 µg/L (limit 3). Not detected: alachlor in 22 samples, chromium in 8 samples, cadmium in 8 samples, barium 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 | 22 | 5 of 22 | 1.1 µg/L | 0 |
| Alachlor | Farm chemical | 2 µg/L | 22 | 0 of 22 | not detected | 0 |
| Chromium | Metal | 100 µg/L | 8 | 0 of 8 | not detected | 0 |
| Cadmium | Metal | 5 µg/L | 8 | 0 of 8 | not detected | 0 |
| Barium | Metal | 2,000 µg/L | 8 | 0 of 8 | not detected | 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, 1 of 1,348 routine total coliform samples taken in the distribution system at Wilmington City tested positive (0.07%); in 2019, the last year on file, 1 of 172 did. E. coli was never found in the 1 sample 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 Wilmington City adjusts the fluoride level to the recommended level for preventing tooth decay.
EPA's treatment table lists fluoridation among the steps at Wilmington City.
Measured fluoride: every sample at the plant's entry points in 2019 was below the 0.2 mg/L reporting limit; detected samples in earlier years ran from 0.2 to 0.24 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 not detected in 4 UCMR 5 samples at Wilmington 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.
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.
At the intake, microcystin was detected 64 times in 311 raw-water samples, across 7 bloom seasons (2017 to 2026); the highest raw-water result was 12.8 µg/L on June 6, 2017. The highest raw-water result since 2024 was 6.66 µg/L.
Microcystin was never detected in treated water (245 samples).
In all, 556 samples from 2016 to 2026, the latest on August 19, 2026.
| Water | Samples | Detections | Highest result |
|---|---|---|---|
| Raw water, at the intake | 311 | 64 | 12.8 µg/L |
| Treated water | 245 | 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
EPA estimated the service area of Wilmington City with a computer model rather than drawing it from the utility's map, so its edges are approximate.
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 OH1401211 (EPA ECHO).
Wilmington City's own pages: wnewsj.com, wnewsj.com
Notable facts: wilmingtonohio.gov, wilmingtonohio.gov, gemgrp.com, library.municode.com
History: wilmingtonohio.gov, gemgrp.com, wilmingtonohio.gov, wnewsj.com
Water quality: gemgrp.com, wilmingtonohio.gov
Planned work: wilmingtonohio.gov
Water pressure: wilmingtonohio.gov, gemgrp.com
Capital projects: wilmingtonohio.gov, wilmingtonohio.gov, wnewsj.com, wilmingtonohio.gov
Rates: library.municode.com, wilmingtonohio.gov
Sewers: wilmingtonohio.gov, wilmingtonohio.gov, wilmingtonohio.gov, library.municode.com
Treatment: wilmingtonohio.gov, gemgrp.com
Supply stress: gemgrp.com, wilmingtonohio.gov, wnewsj.com