Photograph of  this open well in a home basement - many concerns Stain-generating Contaminants in Water
Black, red, white, yellow, green stains from water supply: copper, iron, manganese, sulphur & tannins in water; odors & iron/manganese bacteria

  • WATER STAINING CONTAMINANTS - CONTENTS: explanation of the causes & sources of stains traced to the building water supply or supply piping: what are the sources of black, brown, green, red, yellow, or other stains in or caused by the building water supply, piping, water treatment equipment, water softener, water filter, or water piping?
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Stains & odors in the water supply:

Here we explain of the causes & sources of stains traced to the building water supply or supply piping: what are the sources of black, brown, green, red, yellow, or other stains in or caused by the building water supply, piping, water treatment equipment, water softener, water filter, or water piping.

Some of these staining contaminants in the water supply can explain water odors such as smells of sewage, fuel oil, even cucumbers. And some of these water stainers can tell us something about the need to protect the water piping system from corrosive or aggressive water.

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Stains from the Water Supply

Sulphur bacteria stains in toilet tank (C) Daniel FriedmanSeveral common chemicals, including minerals familiar to most homeowners can colour the water supply or produce stains on plumbing fixtures, in the laundry, in the water softener, and on clothing. This article sumamrizes these water stain sources and summarizes the typical filters or water treatment methods used to correct these conditions.

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Article Contents

Black Stains on Plumbing Fixtures, Laundry, Other Surfaces Traced to Water Contaminants: Sulphur, Manganese or Particulate Sources

The black stains and crud in the toilet tank shown at left are most likely due to an unusually high level of sulphur in the water supply to the building where this toilet is installed. The water also smelled like "rotten eggs" adding weight to that hypothesis.

Photo courtesy of Kingston New York home inspector Arlene Puentes (see REFERENCES).

Look for sulphur in the water supply as well as organic debris, silt, mud, or other inoragnic contaminants. Also look for black sulphur deposits in water piping that ultimately appears as debris in the water supply.

Treatments for Iron or Manganese or Iron/Manganese bacteria in the Water System

and also

Manganese contamination in the water supply

A second common source of black stains and fine particulates in water supply systems (or in the toilet cistern shown above) is manganese. Manganese enters the water supply in areas where ground water or the aquifer is acidic, fostering the dissolution of manganese from manganese-bearing rock and soil through which the water passes.

The manganese level in a building water supply may be made more apparent (as black sludge or deposits or as dark or black stains on laundry) when acidic, manganese-bearing water interacts with organic matter that is also in the water supply. Thus we're more likely to see higher levels of black manganese staining in buildings supplied by water from a dug well, shallow well or other shallow water source.

As we discuss below at RED STAINS from WATER SUPPLY , Gallianella bacteria that can metabolize manganese may form a black slime or sludge layer in toilet tanks, water tanks, piping and well interiors. Manganese-loving bacteria may also be an odor source in the water supply. A BART, or Biological Activity Reaction Test can determine if this type of bacteria is present in your water supply.

On occasion we find black debris in the water supply from other sources including organic debris and even damaged water pump impeller parts. But if the water smells like sulphur, that's the probable cause.

Manganese Contaminant Limits in Drinking Water

Treatments for Iron or Manganese or Iron/Manganese bacteria in the Water System

Brown Stains on Plumbing Fixtures or Fabrics Traced to Water Supply Contaminants

Tub stains can indicate water contaminants (C) Daniel Friedman Enameled cast iron sink photos (C) Daniel Friedman

Stains on plumbing fixtures may be due to simply poor housekeeping or to contaminants in the water supply, or as shown on the porcelain-coated tub and on the pink cast iron sink above, a combination of the two. At the sink a protracted drip at the faucet left brown stains on the fixture surface.

Green Stains on Plumbing Fixtures or Fabrics Traced to the Water Supply or Water Piping: Copper in Water, Corrosive water

Where the building's water color has a greenish or bluish caste, look for water with a high corrosivity index, copper water supply piping, or copper in the water source itself.

Copper in the water supply tends to leave a greenish-blue stain on white surfaces such as porcelain sinks or tubs, or beneath shower heads, particularly where there has been a drippy faucet or shower head. The green stains on the faucet mouth shown below (left) may be due to corrosive water and the white deposits are almost certainly a calcium or similar mineral deposit characteristic of water high in mineral content.

Photo of mineral clogging of a faucet strainer

The level of copper that may be absorbed into water from copper supply piping depends on the corrosivity index of the water supply. Some literature describes this as "aggressive water" meaning that the water chemistry can aggressively or powerfullly-dissolve metals from the piping system. Water that is high in Co2 (carbon dioxide) or O2 (oxygen) or water that has a high acid due to having passed through rock high in natural acids is corrosive and tends to dissolve brass and copper pipes and plumbing fixtures.

Details are

Methods for Treating Copper Building Pipes Producing Green Stains in Water or on Fabrics & Fixtures


Red Stains on Plumbing Fixture or Fabrics: Iron in Water - red-yellow slime, clogs, diesel oil odors, sewage odors

Iron stains on a sink (C) Daniel Friedman Iron stains on a sink (C) Daniel Friedman

Iron in water is a common cause of red stains on clothes as well as red deposits on sinks or tubs where there have been dripping faucets. Iron is common in the earth in most areas and can be dissolved by and thus present in water supplies. In buildings where water supply piping is made of iron or steel, as those pipes age and rust red stains in the water supply or on the laundry may be due to the pipes even if iron is not present at high levels in the incoming water supply.

The red stains produced by iron in the water supply are deposits of either ionic ferrous iron (produced as iron in the water reacts with oxygen also in the water) or of ferric iron, a more stable compound more likely to be the actual compnent of red stains you see.

Red iron-related stains may also come from decaying organic materials in the water supply or from "iron bacteria: (Gallianella bacteria) that digest ferrous iron in the water supply. Iron-bacteria are more commonly found in water from dug wells or shallow wells in from surface water.

The iron-eating baceria are not themselves a health hazard but the presence of this ferro-philic bacteria in your water supply may explain unpleasant odors (and may occur simultaneously with sulphur in the water supply). The smell from iron-bacteria in water is often described as a "fuel oil" odor and some sources reported describe it as a "cucumber odor in water" or as sewage. It's that "sewage smell" that can also be confused with the "rotten egg" smell of sulphur-contaminated water supplies.

Iron deposits that accumulate on a foot valve, well screen, or on a driven point well tip can clog the water entry points and thus reduce well yield.

The Water Quality Association in the U.S. points out that

"Harmless organic compuonds from decaying vegetation in water also may react with iron to cause severe staining. 'Iron bacteria,' which use iron in their metabolic processes, may also cause problems [with red stains on fabrics or fixtures]." - WQA (undated).

Red stains & deposits in a toilet cistern (C) Daniel FriedmanHigh iron levels in water passing through rusty, corroding iron or steel pipes may correlate also with corrosive or aggressive water chemistry that speeds the corrosion process.

Finaly, the presence of a yellow or orange-coloured slime inside a water storage tank (no you never there) or in a toilet tank (where you can look) is a good indicator that your water supply contains iron-loving bacteria.

It's possible that the pink crust in the toilet tank shown at left is a left-over from a combination of high mineral content and high iron content in the water supply to the building where this toilet was installed.

For dealing with iron-bacteria, try disinfecting the well as well as the building water piping and water tank.

However just shocking the well may be little more than a "band-aid" cure since the disinfectant may be unable to kill off thick layers of iron-bacterial slime in the well or piping system.
See WELL CHLORINATION SHOCKING PROCEDURE and increase the wait time before flushing out the chlorine disinfectant.

Iron Contaminant Limits in Drinking Water

Methods for Treating or Removing Iron & Manganese in the Water Supply

All of the iron or manganese water treatment methods above are discussed further

Yellow Stains on Plumbing Fixtures Traced to Water Contaminants: Tannins

Yellow stains on porcelain surface of an antique commode (C) Daniel Friedman

The vertical yellow stain trace to the left of the water entering this antique wood-seated commode may be due to tannins in the water supply. Tannins can impart a yellow hue to water and may leave yellow stains on fabrics washed in tannin-laden water. Particularly where running water from protracted leaks or drips has been present tannins can produce a yellow stain on the porcelain surface of a sink toilet, or tub or on other china surfaces.

Tannins are an aesthetic issue, not a health issue in the building water supply and are typically found in water sources filtered through peaty soils such as those in the following areas:

In Canada tannins are common in the Maritime Islands and in some areas of B.C.

In the U.S. tannins are commonly found in water supplies around the Great Lakes (see Gooseberry Falls north of Two Harbors MN where the water runs brown). In U.S. water supplies in the Southeast, Northwest, and in portions of New England tannins are also common in water.

Methods for Removing Tannins from the Building Water Supply System


White Stains on Plumbing Faucets, Fixtures, Shower Heads or on Plumbing Fixtures: hard water, calcium, other minerals

Photo of a mineral-coated bathroom shower head Bathtub stains hard water (C) D Friedman



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