Water system
Montgomery County Water Services 1
EPA ID OH5701315 · Montgomery County · 150,207 people served · owned by a local government
Montgomery County Water Services 1 buys its water from Dayton Public Water System.
The system's record
- Aquifer
- Great Miami Buried Valley Aquifer
- Water bodies
- Great Miami River, Mad River
- Raw intakes
- Dayton Miami
Dayton Mad River - Active wells
- 105
- Serves
- 141,407 people · Montgomery County
- EPA ID
- OH5703512
About this area's water
Did you know
- The Great Miami Buried Valley Aquifer holds roughly 1.5 trillion gallons and is the sole drinking water source for about 400,000 people around Dayton.
- It was designated a federal Sole Source Aquifer in May 1988, one of a small number nationwide.
- Montgomery County's environmental lab, opened downtown in December 2023, occupies a renovated former child-care building next to the County Administration Building.
- Monitoring wells upstream of Dayton's production wells have shown PFAS from Wright-Patterson at several hundred times the new federal drinking water limits.
History5
- 1988The Great Miami Buried Valley Aquifer, Dayton's sole water source, was designated a federal Sole Source Aquifer in May 1988.
- 2017An Ohio EPA source water assessment found the aquifer feeding Dayton's wellfields highly susceptible to contamination.
- 2021The City of Dayton began litigation with the U.S. Department of Defense over PFAS migrating from Wright-Patterson Air Force Base.
- 2023Montgomery County's environmental laboratory moved in December into a renovated 10,000 sq ft downtown Dayton building, replacing a 1970s Moraine facility.
- 2026Dayton sued Wright-Patterson AFB in Cincinnati federal court on Feb 19, seeking more than $300 million for PFAS treatment and cleanup.
Treatment & pressure
How it is treated
Buried-valley aquifer wells feed Dayton's Miami and Ottawa plants, where the water is lime-softened, filtered, chlorinated and fluoridated. PFAS-affected Ottawa water is currently handled by blending between the two plants rather than by dedicated treatment.
Water pressure
not published; no pressure or pressure-zone figures appear in the county water quality report or the utility rate documents
What it costs
$6.95 per 1,000 gallons
Typical household bill about $40 a month for water.
2026 water only: $50.96 per 1,000 cf single-family plus a $1.00 well-field charge (=$6.95/1,000 gal), plus $18.95 service and $7.45 capital per quarter on a 5/8-in meter
Water quality & impurities8
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| PFOS Ottawa plant average, range 5.45-13.67; above the new federal MCL, compliance due 2029 | 8.81 ppt | 4.0 | 2025 |
| PFHxS Ottawa plant average, range 6.7-23.32; above the new federal MCL | 13.53 ppt | 10 | 2025 |
| PFOA Ottawa plant average, range <2.0-4.5; below the MCL. Miami plant was <2.0 | 2.97 ppt | 4.0 | 2025 |
| TTHM north system locational running average, range 18.2-57.3; south system 30.1 | 44.9 ppb | 80 | 2025 |
| HAA5 north system, range <6-24.6; south system below the reporting limit | 6.2 ppb | 60 | 2025 |
| Nitrate Miami plant highest, range <0.10-1.71; Ottawa plant 1.44 | 1.71 ppm | 10.0 | 2025 |
| Lead (90th pct) no samples over the action level in 32 north or 54 south samples | <5 ppb | AL=15 | 2025 |
| Copper (90th pct) north 0.0407, south 0.056; no exceedances | 0.041-0.056 ppm | AL=1.3 | 2025 |
EPA compliance record
Lead at the tap: 90th-percentile result 0 ppb in 2025 (action level 15 ppb).
EPA health-based violations since 2015:
- 2017Lead and Copper Rule · water quality limits for corrosion control not met · returned to compliance
EPA's count of 2 includes 1 repeat quarterly violation of the problems listed.
2 violations of any kind logged since 2020: 2 for required testing that was missed or reported late.
EPA compliance record · Dayton Public Water System (treats the water)
Lead at the tap: 90th-percentile result 0 ppb in 2023 (action level 15 ppb).
EPA record: no health-based violations since 2015.
Projects & plans4
Recent and current work
- Miami Well Field 36-inch raw water main (Phase A) · $7.5 million
added raw water transmission capacity; funded by a WIIN grant through Ohio EPA. Completion date not stated. - Rip Rap Well Field improvements · $8 million
four new groundwater wells adding 12 MGD of capacity; funded by two Ohio EPA DEFA loans. Completion date not stated. - Montgomery County Environmental Laboratory relocation · 2023 · completed
10,000 sq ft downtown Dayton lab, ARPA-funded, running ~11,000 samples and 38,000 tests a year
Planned or needed
- Ottawa plant PFAS filtration system · $384 million · planned
Dayton seeks $384M to build it plus $70M for 20 years of upkeep; $14.9M in Ohio EPA emerging-contaminant funding approved in 2022
Supply stress
Dayton's sole source, the Great Miami Buried Valley Aquifer, was rated highly susceptible by Ohio EPA in 2017: thin clay cover, shallow depth, surface-water recharge and known plumes in the wellfield protection area. PFAS from Wright-Patterson's Area A shows in monitoring wells upstream of production wells at hundreds of times the new…
Sewers
Sanitary
Montgomery County Environmental Services runs the sanitary sewers and two water reclamation facilities, Eastern Regional and Western Regional, and maintains more than 1,400 miles of water mains. The 2026 county sewer volume charge is $53.78 per 1,000 cf plus service and capital charges.
Storm
No separate stormwater utility fee appears in Montgomery County's 2026 schedule of water and sewer rates; stormwater arrangements vary by member community.
Sourcesverified
Compiled from the utility's own reports and public records, then independently re-checked against primary sources.
Main supplier in 5 ZIP codes
Serves
Main water supplier in 5 ZIP codes
- 45429 · Kettering and Dayton97% of residents
- 45459 · Centerville and Dayton92% of residents
- 45439 · Moraine and Dayton82% of residents
- 45458 · Washington Township and Dayton80% of residents
- 45440 · Kettering and Dayton56% of residents
Also present in 10 more ZIP codes
- 45420 · Dayton37% of residents
- 45409 · Dayton34% of residents
- 45419 · Oakwood and Dayton31% of residents
- 45449 · West Carrollton and Dayton30% of residents
- 45431 · Beavercreek and Dayton29% of residents
- 45404 · Dayton22% of residents
- 45342 · Miamisburg20% of residents
- 45432 · Beavercreek and Dayton20% of residents
- 45414 · Harrison Township and Dayton4% of residents
- 45424 · Huber Heights and Dayton1% 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
Montgomery County Water Services 1 buys its water from Dayton Public Water System.
1 system on record buys water from Montgomery County Water Services 1: Greene County - Clyo.
What the records show about Montgomery County Water Services 1
Who runs it
EPA's record describes Montgomery County Water Services 1 as owned by a local government. It has 52,435 service connections and serves 150,207 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 937-781-2662.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
Montgomery County Water Services 1 buys water that Dayton Public Water System treats first, so the steps that count are the seller's. EPA's treatment table registers these steps for Dayton Public Water System: corrosion control, coagulation and settling, chlorine disinfection, fluoridation, lime softening, and sand or media filtration.
Montgomery County Water Services 1 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 counts 2 health-based violations for Montgomery County Water Services 1 since 2015. Health-based means a contaminant above its legal limit or a required treatment step not carried out. They fall into 1 separate problem (one contaminant or rule in one year); the table lists it.
EPA logs a violation for each compliance period a problem lasts, so the count of 2 includes 1 repeat entry of the problems listed.
EPA logs 2 violations of any kind since 2020: 2 for required testing that was missed or reported late.
| Year | Contaminant or rule | Kind | Measured | Limit | Status in EPA's record |
|---|---|---|---|---|---|
| 2017 | Lead and Copper Rule | water quality limits for corrosion control not met | not on file | not on file | returned to compliance |
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 Montgomery County Water Services 1 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 3.4 ppb, in the period ending December 2024.
EPA has 9 sampling periods on file for Montgomery County Water Services 1 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 Montgomery County Water Services 1 sent EPA, 49,666 lines are counted.
| Material | Lines |
|---|---|
| Lead | 370 |
| Galvanized, needing replacement | 156 |
| Unknown material | 16,665 |
| Not lead | 32,475 |
| All lines | 49,666 |
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 Montgomery County Water Services 1 in 2023 to 2024 and measured 29 PFAS.
The highest PFOA or PFOS result, 9.6 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 PFHxS 10.7 ng/L, PFOS 9.6 ng/L, and PFPeA 5.2 ng/L.
The hazard index for the PFHxS, PFNA, GenX and PFBS mixture reached 1.07 in the worst sample; above 1 would exceed the 2024 mixture limit, which EPA proposed in May 2026 to withdraw.
The system reported potential PFAS sources near its supply.
Ohio EPA's own statewide sampling tested 2 plants of Dayton Public Water System (latest sample February 2021). The highest result was PFHxS at 7.7 ppt (ppt is the same unit as ng/L), against Ohio's action level of 140 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 2 plants of Dayton Public Water System as sampled, most recently April 2026.
| Compound | Highest result | Federal limit |
|---|---|---|
| PFOA | not detected | 4 ng/L |
| PFOS | 9.6 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 Montgomery County Water Services 1's samples in 2019, the last year it was sampled, was 27.4 µg/L. The worst yearly average was 30.2 µg/L and the highest single sample was 53.2 µg/L, from 128 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 5.5 µg/L. The worst yearly average was 5.8 µg/L and the highest single sample was 10.8 µg/L, from 128 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 27.4 µg/L (2019) | 30.2 µg/L | 53.2 µg/L | 128 |
| HAA5 | 60 µg/L | 5.5 µg/L | 5.8 µg/L | 10.8 µg/L | 128 |
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 Montgomery County Water Services 1 buys is treated by Dayton Public Water System, so the results below are Dayton Public Water System's.
Nitrate: the highest of 260 samples was 1.9 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 31 samples (limit 10 µg/L).
| Contaminant | Samples | Highest result | Limit | Samples over limit |
|---|---|---|---|---|
| Nitrate (as nitrogen) | 260 | 1.9 mg/L | 10 mg/L | 0 |
| Arsenic | 31 | 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 Dayton 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 Dayton Public Water System.
Solvents and fuels
The water Montgomery County Water Services 1 buys is treated by Dayton Public Water System, so the results below are Dayton Public Water System's.
EPA's file holds results for all six solvent and fuel compounds it checked. trichloroethylene (TCE) was detected in 1 of 98 samples, highest 1.06 µg/L (limit 5). Benzene, carbon tetrachloride, 1,2-dichloroethane, tetrachloroethylene, and vinyl chloride were not detected in 98 samples each.
| Compound | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|
| Benzene | 5 µg/L | 98 | 0 of 98 | not detected | 0 |
| Carbon tetrachloride | 5 µg/L | 98 | 0 of 98 | not detected | 0 |
| 1,2-dichloroethane | 5 µg/L | 98 | 0 of 98 | not detected | 0 |
| Trichloroethylene (TCE) | 5 µg/L | 98 | 1 of 98 | 1.06 µg/L | 0 |
| Tetrachloroethylene (PCE) | 5 µg/L | 98 | 0 of 98 | not detected | 0 |
| Vinyl chloride | 2 µg/L | 98 | 0 of 98 | 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 Dayton Public Water System.
Farm chemicals and metals
The water Montgomery County Water Services 1 buys is treated by Dayton Public Water System, so the results below are Dayton Public Water System's.
EPA's file holds results for 8 of the nine herbicides and metals it checked. Detected: barium in 31 of 33 samples, highest 94.2 µg/L (limit 2,000). Not detected: atrazine in 18 samples, alachlor in 18 samples, chromium in 31 samples, cadmium in 31 samples, mercury in 22 samples, selenium in 28 samples, thallium in 22 samples.
| Substance | Kind | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|---|
| Atrazine | Farm chemical | 3 µg/L | 18 | 0 of 18 | not detected | 0 |
| Alachlor | Farm chemical | 2 µg/L | 18 | 0 of 18 | not detected | 0 |
| Chromium | Metal | 100 µg/L | 31 | 0 of 31 | not detected | 0 |
| Cadmium | Metal | 5 µg/L | 31 | 0 of 31 | not detected | 0 |
| Barium | Metal | 2,000 µg/L | 33 | 31 of 33 | 94.2 µg/L | 0 |
| Mercury | Metal | 2 µg/L | 22 | 0 of 22 | not detected | 0 |
| Selenium | Metal | 50 µg/L | 28 | 0 of 28 | not detected | 0 |
| Thallium | Metal | 2 µg/L | 22 | 0 of 22 | 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 Dayton 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 Dayton Public Water System.
Bacteria in the pipes
From 2012 to 2019, 17 of 11,641 routine total coliform samples taken in the distribution system at Montgomery County Water Services 1 tested positive (0.15%); in 2019, the last year on file, 2 of 1,454 did. E. coli was never found in the 11,699 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 Montgomery County Water Services 1 buys its water from Dayton 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 Dayton Public Water System, which treats the water Montgomery County Water Services 1 buys.
Measured fluoride: 0.88 mg/L on average leaving the plants of Dayton Public Water System, which supplies Montgomery County Water Services 1, in 2019 (in the range dentists aim for); samples ran from 0.84 to 1 mg/L across 16 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 Montgomery County Water Services 1, last sampled in 2024 (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
The water Montgomery County Water Services 1 buys is treated by Dayton Public Water System, so the results below are Dayton Public Water System's.
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 164 raw-water samples.
Microcystin was never detected in treated water (199 samples).
In all, 363 samples from 2016 to 2026, the latest on May 19, 2026.
| Water | Samples | Detections | Highest result |
|---|---|---|---|
| Raw water, at the intake | 164 | 0 | not detected |
| Treated water | 199 | 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 Montgomery County Water Services 1 comes from the utility's own map.
Counting the people who live in the ZIP codes it overlaps, this atlas estimates 149,377 residents are inside the boundary, 99% of the 150,207 people Montgomery County Water Services 1 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 — 15 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 OH5701315 (EPA ECHO).
Montgomery County Water Services 1's own pages: mcohio.org, mcohio.org, daytonohio.gov
