The Causes of Brownish or Dirty Well Water

The Virginia Master Well Owner Network (VAMWON) is an organization of trained volunteers dedicated to promoting the proper construction, maintenance, and management of private water systems (wells, springs, and cisterns) in Virginia. The Cooperative Extension Services in Virginia manages the program and have numerous publications and fact sheets that can help homeowners make educated decisions about their drinking water. The volunteers can help homeowners interpret their test results and make educated decisions about what treatment might be appropriate and desirable or appropriate solutions to problems..

VAMWON Notes from the Field are a series of stories of the questions and sometimes the solutions I’ve encountered as a VAMWON volunteer. The VAMWON volunteer or Agent can help you identify problems with the water system and provide information on suggested treatments options and other solutions. You can find your VAMWON volunteer neighbor through this link by entering your county in the search box.

I received the following in an e-mail “A week ago Monday we had slightly brown water. I called the landlord who came by to say he was having a plumber look at the well situation. He stated with all the rain we have been having it has had an effect on the well. Yesterday morning I noticed brown water again. I called the landlord who had the plumber call who parroted that all the rain had caused cloudy water.”

Before you call a plumber, well driller, or water treatment company you should test your water so that the problem can be properly diagnosed. It is cheaper to test your water than call a plumber and you need to understand what the real problem is to correct it. First, verify that both the hot water and cold water are both discolored. If the hot water only is discolored then the problem might be with rust the hot water heater. After determining that the brown water is coming from the cold water tap also, it is still possible that there is rust in the plumbing fixtures or the piping, but it would typically manifest in only one sink or tub and not uniformly throughout the house (unless the rust is in the main water pipe from the well). However, it is to be noted that when a water supply has been shut off for a period of time any rust in the systems is likely to be dislodged when the water supply is turned back on. This is true for wells and public supply water systems.

After rust in the household fixtures there are three likely causes for well water to be brown or brownish, surface infiltration, well collapsing or water level dropping or iron (and/or manganese) in the water. Earthquakes can also cause a change in water, either by loosening fine grains of silt and soil or lowering the water level. According the the US Geological Survey there is no rhyme or reason to which wells will be impacted by an earthquake, but time might restore your well. A complete water test to determine the source and extent of your problem and possible treatments or solutions should include tests for manganese concentration, iron concentration, iron bacteria, pH, hardness, dissolved solids as well as the tests for total coliform, fecal coliform and e-coli bacteria.

Surface infiltration of water is due to impaired pump and casing system. In this instance this would seem to be what the landlord was insinuating with the comment about all the rain. A properly functioning well with a sanitary well cap should not be impacted by rain. The pump system consists of the well cap, well, and grouting. Surface flooding, excessive rain or snow melt could flow down the casing area if the grouting is damaged or the well cap not sealed properly. This of course would also allow bacteria from the surface to enter the well. Testing the well for bacteria would determine if the water were safe to drink and would indicate if there was surface infiltration.

A bacteria test checks for the presence of total coliform bacteria and fecal coliform bacteria. These bacteria are not normally present in deeper groundwater sources. They are associated with warm-blooded animals, so they are normally found in surface water and in shallow groundwater(less than 20-40 feet deep). Most bacteria (with the exception of fecal and e-coli) are not harmful to humans, but are used as indicators of the safety of the water. An inspection of the well and pump system might visually locate any obvious flaws but the presence of coliform surface bacteria would certainly identify where to begin looking.

The second likely source of brown water is from the well itself. It is typical in Virginia not to have well casing beyond 40-50 feet deep. The Balls Bluff Siltstone and red clay common to this area does not typically need a casing. The most common modern well installation is to have a pump that installed in the well and looks a little like an outboard motor on a stick. Changes in water level or supply could result in the pump pulling up a bit of mud or the pump could have wracked a bit and is hitting the side of the well hole. So that water that suddenly turns brown may indicate a problem with the well structure or water level.

The third likely source of brown water is iron (and/or manganese) in the water. As rain falls or snow melts on the land surface, and water seeps through iron-bearing soil and rock, iron can be dissolved into the water. In some cases, iron can also result from corrosion of iron or steel well casing or water pipes. Iron can occur in water in a number of different forms. Iron is harmless, but can affect taste and use of water. An appropriate response to the presence of iron is to install the right treatment system.

The type of iron present is important when considering water treatment. Water that comes out of the faucet clear, but turns red or brown after standing is “ferrous” iron, commonly referred to as “clear-water” iron. Water which is rust colored, red or yellow when first drawn is “ferric” iron, often referred to as “red- water” iron. Iron can form compounds with naturally occurring acids, and exist as “organic” iron. Organic iron is usually yellow or brown, but may be colorless. A combination of acid and iron, or organic iron, can be found in shallow wells and surface water. Although this kind of iron can be colorless, it is usually yellow or brown.

Finally, when iron exists along with certain kinds of bacteria you may get bacterial iron that leaves a reddish brown or yellow slime that can clog plumbing and cause an offensive odor. You may notice this slime or sludge in your toilet tank when you remove the lid. Before you attempt to solve any water problem that appears to be iron-related, it is important to have your water tested. A complete water test to determine the extent of your iron problem and possible treatment solutions should include tests for iron concentration, iron bacteria, pH, dissolved solids, hardness as well as the tests for total coliform, fecal coliform and e-coli bacteria. The test results properly interpreted will allow you to address the underlying problem and spend your money to correct the right problem.

Iron and Manganese in Well Water

Many of the perceived problems with well water are caused by the presence of iron and manganese. Iron and manganese can give water an unpleasant taste, odor and color. Iron causes reddish-brown stain on laundry, porcelain, dishes, utensils, glassware, sinks, fixtures and concrete. Manganese causes brownish-black stains on the same items. Detergents do not remove these stains. Chlorine bleach and sodium carbonate may even make the staining worse. Iron and manganese deposits build up in pipelines, pressure tanks, water heater and water softening equipment. These deposits restrict the flow of water and reduce water pressure. More energy is required to pump water through clogged pipes and heat water if the hot water tank’s heating rods are coated with minerals deposits. In addition, water contaminated with iron and manganese often contains iron or manganese bacteria which feed on the minerals. These bacteria do not cause health problems, but can form a reddish brown or brownish black slime in toilet tanks and clog filters.

Iron and manganese are naturally occurring elements commonly found in groundwater in many parts of the country. Interestingly enough, few surface water sources have high levels of these metals. At t levels naturally present in groundwater iron and manganese do not present a health hazard. However, their presence in well water can cause unpleasant taste, staining and accumulation of mineral solids that can clog water treatment equipment and plumbing. In addition, a persistent bacteria/ biofouling problem may be caused by iron bacteria. Under guidelines for public water supplies set by the Environmental Protection Agency (EPA), iron and manganese are considered secondary contaminants. Secondary standards apply to substances in water that cause offensive taste, odor, color, corrosion, foaming, or staining but have no direct impact on health. The standard Secondary Maximum Contaminant Level (SMCL) for iron is 0.3 milligrams per liter (mg/L or ppm) and 0.05 mg/L for manganese. This level of iron and manganese are easily detected by taste, smell or appearance.

Iron and manganese exist in many different chemical forms. The presence of a given form of iron or manganese in geologic materials or water depends on many different environmental factors. Dissolved iron and manganese are easily oxidized to a solid form by mixing with air. In surface water, iron and manganese are most likely to be trapped within suspended organic matter particles. Groundwater tends to be an oxygen poor environment; typically, the deeper the aquifer the less dissolved oxygen is present. Iron and manganese carbonates in an oxygen poor environment are relatively soluble and can cause high levels of dissolved iron and manganese to be carried from a deep well. If sulfur is present in the water then the iron will form iron sulfide rather than iron carbonate and the water may have the familiar unpleasant rotten egg smell. Sometimes oxygen poor conditions can also occur in relatively shallow wells that have stagnant water with very slow turnover. When the iron and manganese are oxidized reddish brown or black particles form and settle out as water stands. These particles are often found trapped in washing machine filters, water treatment equipment, in plumbing fixtures and on clothing, dishes and utensils.

As mentioned above some types of bacteria react with soluble forms of iron and manganese and form persistent bacterial contamination in a water system (especially one with any type of filter or treatment system to capture these iron or manganese bacteria). These organisms are usually found in waters that have high levels of iron and manganese in solution. The reaction changes the iron and manganese from a soluble form into a less soluble form, thus causing precipitation and accumulation of black or reddish brown gelatinous material (slime). Masses of mucous, iron, and/or manganese can clog plumbing and water treatment equipment. They also slough off in globs that become iron or manganese stains on laundry. Bacterial reactions with iron and manganese do not cause any additional precipitation compared to normal exposure to oxygen. However, precipitation caused by bacteria occurs faster and the slime tends to concentrate staining making it more annoying.

All systems of removing iron and manganese essentially involve oxidation of the soluble form or killing and removal of the iron bacteria.  When the total combined iron and manganese concentration is less than 15 mg/l, an oxidizing filter (natural manganese greensand, manufactured silica gel zeolite coated with manganese dioxide, plastic resin beads, or birm, is recommended. Some filters are coated with a manganese oxide and are regenerated by using a potassium permanganate solution. An oxidizing filter supplies oxygen to convert ferrous iron into a solid form which can be filtered out of the water. Synthetic zeolite is a water softener and while it requires fewer backwashes, it can impact the taste of the water, thought anything might be better than the iron and manganese impacts.

Higher concentrations of iron and manganese can be treated with an aeration and filtration system. This system is not effective on water with iron/ manganese bacteria, but is very effective soluble iron and manganese. In this system an aspirator valve pulls air into the water stream to oxidize the iron and manganese to the carbonate form. The air saturated water then enters a precipitator vessel to allow the iron and manganese time to precipitate out and then is passed through a filter. Backwashing the filter is very important to maintain the filter’s function. This system of removal does not involve any chemical additives.

Chemical oxidation can be used to remove high levels of dissolved or oxidized iron and manganese as well as treat the presence of iron/manganese bacteria. The system consists of a small pump that puts an oxidizing agent into the water before the pressure tank. The water will need about 20 minutes for oxidation to take place so treating before a holding tank or pressure tank is a must. After the solid particles have formed the water is filtered often through a sand filter with aluminum sulfate added to improve filtration. The oxidizing agent is used is chlorine, potassium permanganate or hydrogen peroxide. If chlorine is used, an activated carbon filter is often used to finish the water and remove the chlorine taste. Chlorine oxidation requires a pH of 7 +/_ 0.5. Potassium permanganate is more effective on water with a pH above 7.5, but is poisonous and a skin irritant and requires very careful calibration, maintenance and monitoring. Hydrogen peroxide is less pH sensitive.

Careful monitoring and maintenance of a water treatment is necessary to maintain a high quality of treated water. Testing and maintaining your water supply and treatment system is your responsibility. Without regular monitoring, maintenance and adjustments your results are likely to be disappointing.