Common Drinking Water Contaminants and Conditions

Lead is one of the most dangerous elements found in drinking water, especially for young people and infants. Contamination can occur in the water supply from natural deposits, but is most likely a result of pipes leaching inside a house or apartment building. Lead pipes were used extensively in homes and apartment buildings for many years. Many older buildings still use lead pipes for water systems. Today lead pipes have generally been replaced with copper pipes. Lead pipes themselves can be quite safe, however leaching can occur from failed joints or pipe corrosion.

Amount Allowable in Drinking Water: <15ppb

Possible Health Issues from Lead in Drinking Water:

  • Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilities
  • Adults: Kidney problems; high blood pressure
Total Coliform Bacteria
Coliforms are bacteria that are naturally present in the environment and used as an indicator that other, potentially harmful, bacteria may be present. High levels of Coliforms is a warning of potential problems. The major source of Cryptosporidium, Giardia lamblia, and viruses in drinking water is human and animal fecal waste. Fecal coliform and E. coli are only found in human and animal fecal waste. Legionella is found naturally in water and multiplies in hot water heating systems. A major source of cloudiness in drinking water is soil runoff.

Amount Allowable in Drinking Water: Zero

Possible Health Issues from Pathogens in Drinking Water:
  • Disease-causing microbes (pathogens) can cause diarrhea, cramps, nausea, headaches, or other symptoms.
  • These pathogens may pose a special health risk for infants, young children, and people with severely compromised immune systems.
Pesticides are applied to farmlands, gardens and lawns and can make their way into ground water or surface water systems that feed drinking water supplies. Pesticides can be beneficial for the control of pests like weeds and insects, but every pesticide (including organic pesticides) has some level of toxicity to organisms that live in or drink water. Rural wells are particularly prone to pesticide contamination and frequent testing is highly recommended. There are many different types of pesticides, some that may appear to be harmless. The amount of protection required depends on the amount of toxicity, how much is present in the water, and how much exposure occurs on a daily basis. Pesticides are most harmful to humans and animals, including farm animals and pets.

Amount Allowable in Drinking Water:
  • Atrazine:  <3ppb
  • Simazine: <4ppb
Possible Health Issues from Pesticides in Drinking Water:
  • Exposures to pesticides may cause a wide variety of both acute (short-term) and chronic (long-term) health effects, depending upon the type of pesticide and the amount of exposure.  Signs of acute poisoning may include diarrhea, pinpoint pupils, rashes, nausea, headache, and vomiting.  Chronic exposure (greater than 1 year) to some types of pesticides may aggravate asthma symptoms; other types of pesticides may increase the risk for certain types of cancers and birth defects, or cause damage to the genetic and immune systems.
  • Infants and children may be especially sensitive to health risks posed by pesticides because their internal organs are still developing and maturing.  Children eat and drink more in relation to their body weight, possibly increasing their exposure to pesticides in food and water.
  • By law, pesticide-related illness is a reportable condition in some states.  The National Pesticide Information Center (NPIC) has a medical toxicologist on staff that is available to consult with physicians about non-emergency pesticide exposure cases. NPIC can be reached at 1-800-858-7378 for assistance.
Total Chlorine
Chlorine is added to water to control microbes or disinfect the water. When chlorine is added to water, some of the chlorine reacts first with inorganic & organic materials and metals in the water and is therefore not available for disinfection (this is called the chlorine demand of the water). After the chlorine demand is met, the remaining chlorine is called total chlorine. Total chlorine is further divided into: 1) combined chlorine, which is the amount of chlorine that has reacted with inorganic (nitrates, etc.) and organic nitrogen-containing molecules (urea, etc.) to make weak disinfectants that are unavailable for disinfection and, 2) Free chlorine, which is the chlorine that is left over and is available to inactivate disease-causing organisms; it is a measure of the potability of the water. Thus, total chlorine equals the sum of the combined chlorine and free chlorine measurements.

Most city water systems add chlorine to disinfect the water. The chlorine content of city water is constantly measured to assure the proper amount as the water leaves the municipal water system.

Amount Allowable in Drinking Water: <3ppm

Possible Health Issues from Total Chlorine in Drinking Water:
  • Eye/nose irritation; stomach discomfort; anemia
  • Infants and young children: might experience nervous system effects
  • Some feel that high levels of chlorine in drinking water destroy the good bacteria necessary in our digestive system.
Total Hardness
Water hardness is caused by varying quantities of compounds of calcium and magnesium, and by a variety of other metals. Total water hardness is the sum of the concentrations of these metals.

Many municipal water systems remove enough of these compounds to soften water. However, even some city water systems produce moderately hard water. This is usually because the source of the water supply contains significant mineral deposits. Moderately hard waters are common in many rivers of Alaska and Tennessee, in the Great Lakes region, and the Pacific Northwest. Hard and very hard waters are found in some streams in many regions throughout the country. The hardest water (greater than 1,000 mg/L) has been found in streams in Texas, New Mexico, Kansas, Arizona, and Southern California.

Amount Acceptable in Drinking Water: <50ppm

Possible Home Issues from Hard Water in Household Water:
  • Hard water is often indicated by a lack of suds and requires more soap and synthetic detergents for home laundry, bathing and washing dishes
  • Contributes to scaling in boilers and industrial equipment.
  • Hard drinking water is generally not harmful to health
As rain falls or snow melts, water seeps through iron-bearing soil and rock, dissolving iron into the water. In some cases, iron in drinking water can also result from corrosion of iron or steel well casings or water pipes.

Iron is the fourth most abundant mineral in the earth’s crust. Iron gives the hemoglobin of blood its red color and allows the blood to carry oxygen. The iron in a metal pail turns to rust when exposed to water and oxygen. In a similar way, iron minerals in water turn to rust and stain plumbing fixtures and laundry.

Amount Allowable in Drinking Water: <.3ppm

Possible Health Issues from Iron in Drinking Water:
  • The amount of iron in water is usually low and does not present a health problem, and the chemical form of the iron found in water is not readily absorbed by the body.
  • Iron in water can cause yellow, red, or brown stains on laundry, dishes, and plumbing fixtures such as sinks. In addition, iron can clog wells, pumps, sprinklers, and other devices such as dishwashers, which can lead to costly repairs. Iron gives a metallic taste to water, and can affect foods and beverages - turning tea, coffee, and potatoes black.
The pH level indicates the alkalinity or acidity of water. pH affects many chemical and biological processes in the water. For example, different waterborne organisms flourish within different ranges of pH.  A change in the pH of drinking water can occur for a variety of reasons, so testing each year is recommended.

Acceptable pH range in Drinking Water: There is no federally enforceable standard, however it is generally accepted that the pH level should be within the range of 6.5 to 8.5

Possible Health Issues from low or high pH in Drinking Water:
  • The pH of water is not in itself a health concern, however low or high pH levels are indications of issues that require investigation.
  • The pH level of drinking water can change how water looks and tastes. If the pH is too low or too high, it could damage your pipes, cause heavy metals like lead to leak out of the pipes into the water, and eventually make you sick.
  • Acidic water (low pH) can leach metals from plumbing systems which can cause health problems
  • High pH levels can cause bluish green stains on fixtures with copper fittings, reddish stains with galvanized iron pipes and corrosion problems causing plumbing leaks.
Total Alkalinity
Alkalinity is a measure of the capacity of water to neutralize acids. Total alkalinity is determined by measuring the amount of acid (e.g., sulfuric acid) needed to bring the water to a pH of 4.2. At this pH all the alkaline compounds in the sample are "used up."

Small amounts of carbonates are found in natural water supplies in certain sections of the country. Acid rain also contributes to alkalinity in water. Carbonates may be found in the water after lime soda has been used to soften the water. Bicarbonates are the most common sources of alkalinity. 

Acceptable Alkalinity in Drinking Water: There is no federally enforceable standard, however it is generally accepted that the alkalinity level should be less than 180ppm.

Possible Issues from low or high Total Alkalinity in Drinking Water:
  • Usually, an alkaline condition due to bicarbonate ions is not noticeable except when present in large amounts. In contrast, alkalinity is readily detectable in fairly small amounts of carbonate and hydroxide ions.
  • Alkalis in water produce a bitter, objectionable "soda taste" and slippery feel.
  • High alkaline water can cause dry skin.

Copper contamination of drinking water often results from corrosion of plumbing materials inside the home or apartment building, although some copper can enter through erosion of natural deposits into wells. More likely, copper enters the drinking water and leaches through contact with plumbing metal caused by a chemical reaction between water and the plumbing materials. Copper can leach into water from pipes, brass fixtures and faucets, and pipe fittings.

The amount of copper in your water also depends on the types and amount of minerals in the water, how long the water stays in the pipes, the amount of wear in the pipes, the water’s acidity and its temperature.

You cannot see, taste, or smell copper dissolved in water, so testing is the only sure way of telling whether there are harmful quantities of copper in your drinking water. You should be particularly suspicious if your home has copper pipes and be sure to test your water every year.

Amount Allowable in Drinking Water: <1.3ppm

Possible Health Issues from Copper in Drinking Water:
  • With short term exposure, experience gastrointestinal distress
  • With long-term exposure, possible liver or kidney damage
  • People with Wilson's disease should consult their doctor if the amount of copper in their water exceeds the allowable level.
Iron Bacteria
Iron Bacteria is a type of bacteria that feeds on small amounts of iron in water. Since iron is a very common mineral found in the ground, iron bacteria is fairly common in ground water wells. Iron bacteria often colonizes in the well and coats the walls of the casing with a slimy mass. It typically does not exist in municipal water systems.

Iron bacteria can produce a sticky slime in the water, cause an unpleasant taste and smell like sewage or rotten vegetation; however iron bacteria poses no health risk. Test strips are not needed to detect its presence.
  1. Fill a clear glass with cold water. Allow any discoloration to settle to the bottom. 
  2. If the sediment has a feathery appearance, iron bacteria is present. If the sediment is rusty powder, iron bacteria is not present.
Acceptable Level of Iron Bacteria in Drinking Water: There is no federally enforceable standard.

Possible Issues caused from Iron Bacteria in Drinking Water:
  • Iron bacteria poses no health risk, but the problems to the water system may be significant enough to require treatment.
  • Iron bacteria can produce a sticky slime in the water and cause an unpleasant taste and smell like sewage or rotten vegetation.
  • It can produce gelatinous strands, masses, or thin films that plug pipes, toilets, plumbing fixtures and even the well itself. If the problem progresses, water flow from the well can be reduced.
Nitrate and Nitrite 
Nitrate and its chemical brother, Nitrite, are colorless, odorless, and tasteless compounds present in some groundwater. The formation of nitrates is an integral part of the nitrogen cycle in our environment and is a naturally occurring form of nitrogen found in soil. Common sources of nitrate is from fertilizers, manure, municipal waste water treatment and septic tanks. Rain or irrigation water can leach nitrate into groundwater. Once taken into the body, nitrates are converted to nitrites.

Amount Allowable in Drinking Water:
  • Nitrate: <10ppm
  • Nitrite:  <1ppm
Possible Issues caused from Nitrate in Drinking Water:
  • In moderate amounts, nitrate is harmless in drinking water.
  • Prolonged intake of high levels of nitrate are linked to gastric problems, which have been shown to cause cancer in test animals.
  • If people or animals drink water high in nitrate, it may cause methemoglobinemia or Blue Baby Syndrome, an illness found especially in infants under six months old and pregnant women. Infants should not drink water that exceeds 10 mg/l NO3-N. This includes formula preparation.
Hydrogen Sulfide
Hydrogen sulfide is formed by sulfur bacteria that may occur naturally in water. These bacteria use the sulfur in decaying plants, rocks, or soil as their food or energy source and as a by-product produce hydrogen sulfide. It is found in deep or shallow wells and also can enter surface water through springs, although it quickly escapes to the atmosphere. Hydrogen sulfide often is present in wells drilled in shale or sandstone, or near coal or peat deposits or oil fields.

Since hydrogen sulfide can be detected in water by “rotten egg” smell and taste, test strips are not needed to detect its presence.
  1. Turn on the cold water; let it run for 1 minute and smell. Turn off the cold water.
  2. Turn on the hot water. Let it run of 1 minute and smell the water. 
If the rotten egg smell is present in both, hydrogen sulfide is present in your water supply. If you detect it in the hot water only, the smell is from a reaction in your hot water heater.

Acceptable Level of Hydrogen Sulfide in Drinking Water: There is no federally enforceable standard.

Possible Issues caused from Hydrogen Sulfide in Drinking Water:
  • Water containing hydrogen sulfide usually does not pose a health risk, but does give water a nuisance "rotten egg" smell and taste.
  • Hydrogen sulfide is corrosive, may tarnish copper and silverware, and occasionally releases a black material that stains laundry and porcelain.
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