Water system
Delphos City
EPA ID OH0200412 · Allen County · 7,101 people served · owned by a local government
Delphos City treats its own water from Little Auglaize River, stored in city reservoir.
The system's record
- Water bodies
- Little Auglaize River
- Raw intakes
- Little Auglaize River
Reservoir - Serves
- 7,101 people · Allen County
- EPA ID
- OH0200412
About this area's water

Did you know
- When it opened in 2006, Delphos's sewage plant was the largest flat plate membrane bioreactor facility in the world — and the only membrane plant anywhere running Autothermal Thermophilic Aerobic Digestion on its solids.
- A town of about 7,000 people built a wastewater plant sized for the organic load of 70,000, because its industries put out that much.
- The plant's solids are cooked by their own bacteria: the ATAD reactors hold about 140°F with no external heat, producing a Class A biosolid that gets pressed to roughly 22% solids and spread in city parks or handed to…
- There are 52,000 individual membrane plates in the bioreactor, stacked into 130 double units across five trains — and in a storm the fifth train stops thickening sludge and starts treating sewage.
- The reservoir has its own chapter of city law: Chapter 931 of the Delphos codified ordinances is the Delphos-Gillmor Reservoir.
Source: cityofdelphos.comcityofdelphos.comcodelibrary.amlegal.com
History4
- 2005The city began a wastewater treatment improvement project to handle its unusually high industrial organic loadings, improve effluent quality discharged to Jennings Creek, and meet coming Total…
- 2006The new wastewater plant came online — at the time the largest flat plate membrane bioreactor facility in the world, and the only membrane treatment facility operating with an Autothermal…
- 2025Ohio EPA issued the Delphos Water Plant a warning for failure to meet the requirements for service line notifications; the city posted a lead service line replacement program policy and a service…
- 2026Council authorized a run of wastewater headworks work: new screens from SAVECO North America installed by Peterson Construction (O2026-11, O2026-18, O2026-21), a COG bar screen from Du Peron…
Treatment & pressure
How it is treated
The Delphos Water System takes its raw water from the Little Auglaize River via the Delphos Gilmore Reservoir northwest of the city — the river is impounded first rather than pumped straight to the plant, and the reservoir has its own chapter in the codified ordinances (Chapter 931, Delphos-Gillmor…
Source: cityofdelphos.comcodelibrary.amlegal.com
Water pressure
Not published. Neither the 2025 consumer confidence report nor the Water Department page gives a distribution system pressure figure.
What it costs
Not published online. Delphos bills water and sewer through Muni-Link with payment via AuthorityPay, and the city's Documents & Forms library has a dedicated 'Water Sewer'…
Water quality & impurities10
| Contaminant | Level | Limit | Year |
|---|---|---|---|
| Total trihalomethanes (TTHM) Range 42.80-93.9 ppb — individual results ran above the 80 ppb MCL, though the running annual average stayed compliant… | 62.00 ppb | 80 (MCL) | 2025 |
| Nitrate Range 1.91-5.71 ppm, over half the MCL. Runoff from fertilizer use, leaching from septic tanks and sewage, erosion of… | 5.71 ppm | 10 (MCL) | 2025 |
| HAA5 (haloacetic acids) Range 14.7-20.8 ppb. | 18.53 ppb | 60 (MCL) | 2025 |
| Total chlorine Range 1.34-2.16 ppm. | 1.77 ppm | 4 (MRDL) | 2025 |
| Fluoride | 1.09 ppm | 4.0 (MCL) | 2025 |
| Atrazine Range 0.33-0.55 ppb — detected in every sample, not just occasionally. Runoff from herbicide used on row crops. | 0.41 ppb | 3 (MCL) | 2025 |
| Total organic carbon (TOC) Range 1.9-3.7. TOC has no direct health effect but is the feedstock for trihalomethane and haloacetic acid formation… | 2.4 removal… | Treatment… | 2025 |
| Turbidity Range 0.04-0.15 NTU; 100% of monthly samples met the turbidity limits. | 0.15 NTU… | Treatment… | 2025 |
| Lead 20 samples taken 9 July and 23 July 2025; 0 exceeded the action level, range 0 to 0. | 0 ppb | 15 (action… | 2025 |
| Copper Range 0-0.053 ppm; 0 of 20 samples over the action level. | 0 ppm | 1.3 (action… | 2025 |
Source: cityofdelphos.comcityofdelphos.com
EPA compliance record
Lead at the tap: 90th-percentile result 0 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 & plans8
Recent and current work
- Wastewater treatment plant replacement (membrane bioreactor facility) · 2005-2006 · completed
Begun 2005, online 2006. Designed for the organic loading of a community of 70,000 despite a population near 7,000, with a 12 MGD design peak flow. The largest… - Storm holding pond expansion · 2005-2006 · completed
Enlarged an existing pond to bring the city's storm holding capacity to 12 million gallons, part of the same wastewater project. Cost not published. - Project No. 2025-100 S. Main Street Storm Sewer Project · 2025 · under construction
New storm sewer running from W. Clime Street, begun 15 August 2025 and listed 'In Progress' on the city's projects page as of September 2026. Cost not… - Wastewater plant headworks screen replacement · 2026 · under construction
Screens purchased from SAVECO North America (O2026-11, amended by O2026-18) with removal and installation by Peterson Construction (O2026-21). Costs are in the… - Wastewater plant COG (bar) screen · 2026 · under construction
Screen purchased from Du Peron Corporation (O2026-22) and installed by Peterson Construction (O2026-23). Cost not published on the ordinance index. - 7th Street lift station repair and renovation · 2026 · under construction
Contract with All Purpose Contracting, Inc. (O2026-24). Cost not published on the ordinance index. - Sewer inspection trailer and camera · 2026 · completed
Purchase of a 2023 Envirosight inspection trailer and sewer camera from Best Equipment Company (O2026-25). Cost not published on the ordinance index.
Source: cityofdelphos.comcityofdelphos.comcityofdelphos.com
Planned or needed
- Lead service line replacement program · planned
The city adopted a lead service line replacement program policy and published a service line inventory survey after Ohio EPA warned it in 2025 for failure to…
Supply stress
Not documented as quantity-stressed. Delphos banks Little Auglaize River water in the Delphos Gilmore Reservoir rather than pumping the river directly, which buffers it against low flow, and it maintains a published Surface Water Assessment Plan. The visible pressure is on quality, and it is the classic farm-country surface water…
Sewers
Sanitary
A 2006 membrane bioreactor plant discharging to Jennings Creek, built from 2005 to treat industrial organic loadings equivalent to a community of 70,000 in a city of about 7,000. Average dry weather flow is roughly 1.5 MGD; design peak flow is 12 MGD. Wastewater enters an influent pump station on the old plant site through a 48-inch and…
Storm
Delphos runs a combined sewer system, so storm flow goes to the wastewater plant rather than to a separate outfall network — when it rains the plant sees flows in excess of eight times the 1.5 MGD dry weather average, which is why it was built for a 12 MGD…
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
- 45833 · Delphos64% 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
Delphos 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 Delphos City.
What the records show about Delphos City
Who runs it
EPA's record describes Delphos City as owned by a local government. It has 2,750 service connections and serves 7,101 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 419-695-4010.
Source: EPA Safe Drinking Water Information System (SDWIS), water system record.
How the water is treated
EPA's treatment table registers these steps for Delphos City: corrosion control, coagulation and settling, chlorine disinfection, iron and manganese removal, fluoridation, granular activated carbon, lime softening, sand or media filtration, and ultraviolet disinfection.
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 Delphos 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 September 2026).
Lead and copper at the tap
In the sampling period ending December 2025, the 90th-percentile lead result at Delphos 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 5.3 ppb, in the period ending December 2022.
EPA has 7 sampling periods on file for Delphos City 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 Delphos City sent EPA, 2,892 lines are counted.
| Material | Lines |
|---|---|
| Lead | 1,938 |
| Galvanized, needing replacement | 2 |
| Unknown material | 46 |
| Not lead | 906 |
| All lines | 2,892 |
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 Delphos City in 2024 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 1 plant of Delphos City (latest sample September 2020). Not one of the six PFAS tested (PFOA, PFOS, PFHxS, PFNA, GenX and PFBS) was detected.
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 Delphos City's samples in 2019, the last year it was sampled, was 48.4 µg/L. The worst yearly average was 58.3 µg/L and the highest single sample was 82.8 µg/L, from 60 samples taken from 2012 to 2019.
For HAA5, the average in the last year sampled was 22 µg/L. The worst yearly average was 22.7 µg/L and the highest single sample was 33 µg/L, from 60 samples.
| Byproduct | Limit | Latest yearly average | Worst yearly average | Highest sample | Samples |
|---|---|---|---|---|---|
| TTHM | 80 µg/L | 48.4 µg/L (2019) | 58.3 µg/L | 82.8 µg/L | 60 |
| HAA5 | 60 µg/L | 22 µg/L | 22.7 µg/L | 33 µg/L | 60 |
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 3.62 mg/L (as nitrogen) in 2017; in 2019, the last year sampled, the highest was 1.5 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 | 3.62 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 9 samples each.
| Compound | Limit | Samples | Detected in | Highest result | Samples over limit |
|---|---|---|---|---|---|
| Benzene | 5 µg/L | 9 | 0 of 9 | not detected | 0 |
| Carbon tetrachloride | 5 µg/L | 9 | 0 of 9 | not detected | 0 |
| 1,2-dichloroethane | 5 µg/L | 9 | 0 of 9 | not detected | 0 |
| Trichloroethylene (TCE) | 5 µg/L | 9 | 0 of 9 | not detected | 0 |
| Tetrachloroethylene (PCE) | 5 µg/L | 9 | 0 of 9 | not detected | 0 |
| Vinyl chloride | 2 µg/L | 9 | 0 of 9 | 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: atrazine in 22 of 25 samples, highest 0.69 µg/L (limit 3); barium in 5 of 8 samples, highest 12 µg/L (limit 2,000). Not detected: alachlor in 25 samples, 2,4-D in 1 sample, chromium in 8 samples, cadmium 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 | 25 | 22 of 25 | 0.69 µg/L | 0 |
| Alachlor | Farm chemical | 2 µg/L | 25 | 0 of 25 | not detected | 0 |
| 2,4-D | Farm chemical | 70 µg/L | 1 | 0 of 1 | 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 | 5 of 8 | 12 µg/L | 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 768 routine total coliform samples taken in the distribution system at Delphos City tested positive (0.13%); in 2019, the last year on file, 0 of 96 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 Delphos City adjusts the fluoride level to the recommended level for preventing tooth decay.
EPA's treatment table lists fluoridation among the steps at Delphos City.
Measured fluoride: 1.05 mg/L on average at the plant's entry points in 2019 (in the range dentists aim for); samples ran from 0.86 to 1.08 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 Delphos City, 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
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 78 times in 287 raw-water samples, across 4 bloom seasons (2016 to 2019); the highest raw-water result was 19.2 µg/L on December 24, 2018. There has been no raw-water detection since 2024.
In treated water, microcystin was detected 2 times; the highest result was 0.25 µg/L (December 2025), below the 0.3 µg/L advisory level.
In all, 448 samples from 2016 to 2026, the latest on August 25, 2026.
| Water | Samples | Detections | Highest result |
|---|---|---|---|
| Raw water, at the intake | 287 | 78 | 19.2 µg/L |
| Treated water | 161 | 2 | 0.25 µg/L |
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).
Water and sewer bills
Ohio EPA's 2023 rate survey puts the water bill at Delphos City for a household using 5,000 gallons a month at $907 a year, about $76 a month.
The sewer bill in the same survey is $951 a year at 5,000 gallons a month.
| Use | Water, per year | Sewer, per year |
|---|---|---|
| 2,500 gallons a month | $534 | $529 |
| 5,000 gallons a month | $907 | $951 |
| 8,000 gallons a month | $1,356 | $1,457 |
The survey lists it as “Delphos”. 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 Delphos City comes from the utility's own map.
Counting the people who live in the ZIP codes it overlaps, this atlas estimates 6,802 residents are inside the boundary, 96% of the 7,101 people Delphos 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.
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 OH0200412 (EPA ECHO).
Delphos City's own pages: en.wikipedia.org, vanwert.org
Notable facts: cityofdelphos.com, cityofdelphos.com, codelibrary.amlegal.com
History: cityofdelphos.com, cityofdelphos.com, cityofdelphos.com
Water quality: cityofdelphos.com, cityofdelphos.com
Planned work: cityofdelphos.com, cityofdelphos.com
Water pressure: cityofdelphos.com, cityofdelphos.com
Capital projects: cityofdelphos.com, cityofdelphos.com, cityofdelphos.com
Rates: cityofdelphos.com, codelibrary.amlegal.com
Sewers: cityofdelphos.com, cityofdelphos.com, cityofdelphos.com
Treatment: cityofdelphos.com, codelibrary.amlegal.com
Supply stress: cityofdelphos.com, cityofdelphos.com
