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
Dayton draws groundwater via 105 wells in the Miami Wellfield and Mad River Wellfield (Great Miami Buried Valley Aquifer), which are recharged by and hydraulically connected to the Great Miami and Mad Rivers.
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 · treatment technique violation · 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 of them paperwork (monitoring, reporting, public notice or consumer report).
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 and were not verified this pass.
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.
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
Montgomery County Water Services 1's own pages: mcohio.org, mcohio.org, daytonohio.gov