Orange, black and white shower stains and Central Ohio water
An orange ring at the drain, black spots at a fixture, white crust on the glass: each has a different cause, and only some of them come from the water. This page sets out what EPA ties orange and black staining to, what was measured leaving Central Ohio's public water plants, which systems record removing iron and manganese, and what Ohio EPA reports for well water, from the agencies and the utilities.
Last updated September 2026 · Figures are EPA's, Ohio EPA's, the Ohio Department of Health's and the utilities', each read September 25, 2026 · No prices on this page; the Estimate Builder carries those · Part of the knowledge base
Three colors, three different causes
The U.S. Environmental Protection Agency publishes secondary drinking water standards, which it describes as non-mandatory guidelines for aesthetic qualities such as taste, color and odor, and does not enforce. Two of them explain the colored marks people find in a shower. Above 0.3 milligrams per liter, EPA lists reddish or orange staining for iron; above 0.05 milligrams per liter, black staining for manganese. White crust is hardness, which EPA gives no number for; what Central Ohio's utilities publish about it is on the pages on Columbus water hardness and hardness beyond Columbus. Pink or gray film on shower tile is something else again: the City of Columbus's water report says it comes from microbes in the air, which "do not come from your drinking water."
| Metal | EPA secondary standard | Noticeable effects above it, in EPA's words |
|---|---|---|
| Iron | 0.3 milligrams per liter | Rusty color; sediment; metallic taste; reddish or orange staining |
| Manganese | 0.05 milligrams per liter | Black to brown color; black staining; bitter metallic taste |
| Copper | 1.0 milligrams per liter | Metallic taste; blue-green staining |
Manganese at the water plants
The one measurement of manganese taken the same way at the large Central Ohio public water systems is EPA's fourth Unregulated Contaminant Monitoring Rule, sampled from 2018 to 2020 where water leaves each plant for the mains. All 67 samples at the 17 public water systems it sampled in the seven Central Ohio counties were under the 50 micrograms per liter secondary standard; the highest, 22.5 at a City of Bexley sampling point in 2018, was under half of it. The table shows eleven of those systems; the other six, Bexley, Gahanna, Reynoldsburg, Circleville, the Earnhart Hill Water District and a Madison County school, are left out, and all of their results but Bexley's were under 7. That round did not measure iron, and London, Canal Winchester, Plain City, Pataskala and Granville were not sampled. Of the 2025 water quality reports read for this page, only Columbus's prints an iron line, and it reads not detected; none prints a manganese figure.
| Water system | Where sampled | Samples | Highest manganese, micrograms per liter |
|---|---|---|---|
| Lancaster | North and South plants | 4 | 15.1 |
| Southwest Licking Community Water | Its treatment plant | 2 | 13.1 |
| Del-Co Water | Alum Creek, Olentangy and East Knox plants | 10 | 2.0 |
| City of Delaware | Its plant | 4 | 1.97 |
| Marysville | Its plant | 4 | 0.68 |
| Newark | Its plant | 4 | 0.61 |
| Westerville | Its plant | 4 | 0.55 |
| Columbus | Dublin Road, Hap Cremean and Parsons Avenue plants | 7 | 0.48 |
| Groveport | Its well treatment plant | 2 | 0.46 |
| Pickerington | Its plant | 2 | Not detected |
| Fairfield County Utilities | Its plant | 2 | Not detected |
Which plants remove iron and manganese
EPA's federal drinking water database records the treatment steps at each plant. The systems that draw on rivers and reservoirs record no iron or manganese removal, apart from iron removal at one Marysville plant, while nearly every system that draws on wells records iron removal and several manganese removal as well. The database carries no dates and can lag a plant change, so the table says what it records, not what a plant does today.
| Water system | Water source | Removal recorded |
|---|---|---|
| Columbus, Del-Co Water, Newark, Westerville | Rivers and reservoirs, with wells at some plants | None recorded |
| City of Delaware | River and wells | None recorded in the federal database |
| Marysville | Surface water | Iron, at one plant |
| Lancaster, Pickerington, Canal Winchester, Fairfield County Utilities, Southwest Licking | Wells | Iron and manganese |
| Groveport, Pataskala, Granville, Plain City | Wells | Iron |
| London | Wells | None recorded |
Private wells
Ohio EPA's figures from its ambient ground water monitoring, about 7,750 iron and 7,400 manganese results from wells that are mostly at public water systems, give the untreated levels. Its presentation says iron medians exceed the 300 micrograms per liter secondary standard in all three aquifer types, and manganese medians exceed the 50 micrograms per liter standard in sand and gravel and sandstone but not in limestone. It also notes that adjacent wells can have different levels. What rock or gravel Central Ohio's wells draw from, county by county, is on the page on private wells by county; joining the two is an inference, and only a test of a well says what is in it.
| Aquifer | Iron, median | Manganese, median |
|---|---|---|
| Sand and gravel | 687 | 121 |
| Sandstone | 335 | 89 |
| Limestone and other carbonate rock | 814 | 18 |
The Ohio Department of Health says water treatment installed for aesthetic conditions such as hardness, high sulfur or high iron needs no permit and need not be installed by a registered private water systems contractor. The department, Ohio State University Extension and Ohio EPA publish a web tool that compares a well's laboratory results with the standard and the natural range in Ohio ground water.
Scope, plainly. The plant figures are for water leaving the plant, before it sits in a house's own pipes and water heater, and the database and presentation figures are as published. Nothing here diagnoses a particular stain or recommends a product.
The short version. EPA ties reddish or orange staining to iron above 0.3 milligrams per liter and black staining to manganese above 0.05, as non-mandatory aesthetic guidelines. Every manganese sample EPA took at 17 Central Ohio public water systems from 2018 to 2020 was under that guideline, the highest under half of it. The river and reservoir systems record no iron or manganese removal, apart from iron at one Marysville plant; nearly every well-water system records iron removal. In untreated Ohio ground water, iron is typically above its guideline in every aquifer type, and manganese in sand and gravel and sandstone.
Sources
Every figure, date and quotation on this page comes from one of these documents, read on the date given. Where two of them disagree, the page says so.
- U.S. Environmental Protection Agency, Secondary Drinking Water Standards: Guidance for Nuisance Chemicals, last updated May 26, 2026; read September 25, 2026.
- U.S. Environmental Protection Agency, fourth Unregulated Contaminant Monitoring Rule occurrence data, revised March 2024, Ohio manganese results; read September 25, 2026.
- U.S. Environmental Protection Agency, Envirofacts Safe Drinking Water Information System, treatment records by water system, with EPA ECHO reference codes; read September 25, 2026.
- City of Columbus, 2025 drinking water quality report, and the 2025 report of Plain City; read September 25, 2026.
- Ohio Environmental Protection Agency, Patzke, Kenah and Slattery, Iron and Manganese in Ohio Ground Water, 2017; read September 25, 2026.
- Ohio Department of Health, Private Water Systems, Water Treatment and Information for Homeowners; read September 25, 2026.
Common questions
What causes orange stains in a shower in Central Ohio?
EPA's secondary drinking water standards tie reddish or orange staining to iron above 0.3 milligrams per liter. Those standards are non-mandatory aesthetic guidelines. Iron is common in untreated Ohio well water, and nearly every Central Ohio public system that draws on wells records an iron removal step in EPA's federal database, while the river and reservoir systems record none, apart from one Marysville plant.
What causes black stains around a shower drain or fixture?
EPA's secondary standards tie black staining to manganese above 0.05 milligrams per liter. Every manganese sample EPA took at the 17 Central Ohio public water systems it sampled from 2018 to 2020 was under that level. Gray, black or pink film on regularly moist surfaces is a different thing: the City of Columbus's water report says it comes from microbes in the air, not from the drinking water.
Does Columbus water have iron or manganese in it?
Columbus's 2025 water quality report lists iron as not detected. In EPA's 2020 sampling where water leaves the city's Dublin Road, Hap Cremean and Parsons Avenue plants, the highest manganese result was 0.48 micrograms per liter, against EPA's secondary standard of 50.
Which Central Ohio water systems remove iron at the plant?
EPA's federal drinking water database records iron removal at Lancaster, Pickerington, Canal Winchester, Fairfield County Utilities, Southwest Licking, Groveport, Pataskala, Granville and Plain City, all on wells, and at one Marysville plant. Columbus, Del-Co Water, Newark and Westerville record none.
Is iron in well water common in Central Ohio?
Ohio EPA's ground water monitoring puts the median iron in untreated ground water above EPA's 300 micrograms per liter secondary standard in sand and gravel, sandstone and limestone aquifers alike, and says adjacent wells can differ. Only a laboratory test of a well says what is in it, and the Ohio Department of Health says treatment for high iron needs no permit.
Are iron and manganese stains a health problem?
EPA's secondary standards for iron and manganese are non-mandatory guidelines about taste, color and staining, not health limits. Ohio EPA also notes EPA's separate, non-regulatory lifetime health advisory for manganese of 300 micrograms per liter, well above every Central Ohio result in EPA's 2018 to 2020 sampling.
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