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Michigan State University Extension
Home Maintenance And Repair - 01500633

Why Test?

Water absorbs dissolved minerals, organic compounds and organisms as it moves through the air and soil into surface and ground water supplies. Unacceptable materials may find their way into the water due to some of our activities.

Public water systems are required to regular test and treat water for certain contaminants according to the rules and regulations set by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act. Testing your water from a public system could indicate problems in your home's plumbing, connections or treatment system.

Most private systems are in rural or suburban areas. Private well owners are responsible for monitoring the quality of their water. Testing for possible contaminants on a regular schedule is the only way to be certain your water supply is safe.

Occasional problems do occur in the state's water supplies. Nuisance problems generally do not present a health risk, but the water may not be acceptable for all household activities. The most common nuisance problems are objectionable taste, odor, color and hardness. Once properly identified, these problems can often be corrected with water treatment systems.

Testing for every possible contaminant is unnecessary and expensive. This will help you identify the tests you need for your water supply. Testing confirms a problem exists so appropriate treatment can be recommended and you do not purchase expensive, unnecessary treatment systems.

Which Tests?

Your first concern is to provide your family with a safe source of water. Private well-owners should test for total coliform bacteria and nitrate. The presence or absence of bacteria or nitrate often indicates the safety of your water supply. Testing must be done to detect these contaminants since both are typically invisible, odorless and tasteless.

Coliform bacteria are found in the digestive tract of all birds and mammals. Most coliform bacteria are not harmful themselves, but point to an unsanitary condition and possible presence of disease causing agents. In some cases the bacteria are found in the pipes or well and not the water supply itself.

Sources of nitrate include food, water and soil. High levels of nitrate in the water supply can cause infant cyanosis (blue baby) in children under six months. Chronic, long-term risks are not known at this time. Like coliform bacteria, the presence of nitrate indicates the possibility other contaminants.

The following table lists problems found in water supplies and the appropriate tests to request. You should review your particular concerns with your county Health Department, Cooperative Extension office or water testing lab when selecting the appropriate tests.

Problem or Concern Test  Appearance:
Frothy, Foamy Detergents Black flakes Manganese

Brown or Yellow Iron, Tannic Acid
Stains on fixtures or clothing: Red or Brown Iron

Black Manganese

Green or Blue Copper
Odor or Taste: Bitter Nitrate, Sulfates

Rotten Egg   Hydrogen Sulfide

Metallic  pH, Iron, Zinc, Copper, Lead

Salty  Total Dissolved Solids, Chloride,  Sodium

Septic, Musty, Earthy  Total Coliform Bacteria,Iron

Soapy Detergents (Surfactants)

Gasoline or Oil Hydrocarbon Scan,Aromatic Volatile Organic Chemicals

White deposits on  pots and fixtures,  soap scum Hardness

Discoloration of children's teeth Fluoride

Family or guests become ill Total Coliform Bacteria, Nitrate, Sulfates

Water supply used for infant less than six
months old

Corrosion of plumbing Corrosivity, pH, Lead, Iron, Zinc, Manganese, Copper Sulfates,Chloride

If You Suspect or Observe Test Contamination from:
Old lead pipe or solder Lead, Copper, pH, Zinc
Leaking fuel tank Hydrocarbon Scan, Aromatic Volatile Organic Chemicals
Coal mining Total Dissolved Solids,Iron, Sulfates, pH, Corrosion Index, Manganese, Aluminum,Arsenic, Selenium
Gas and oil drilling Total Dissolved Solids, Chloride, Sodium, Barium,Lead, pH, Corrosion Index, Strontium, Volatile
Organic Scan
Landfill Total Dissolved Solids, pH, Volatile Organic Scan, Heavy Metal Scan
Septic systems Total Coliform Bacteria, Nitrate, Detergents, Total Dissolved Solids, Chloride, Sodium, Sulfates
Land application of sludge Total Coliform Bacteria, Nitrate, Metals (Lead, Cadmium)
Intensive agriculture Total Coliform practices Bacteria, Nitrate, Pesticide Scan, pH, Total Dissolved Solids
Livestock feedlots Total Coliform Bacteria, Nitrate, Total Dissolved Solids, Total Organic Carbons
Road salt Total Dissolved Solids, Chloride, Sodium
When To Test

Private wells should be tested yearly for coliform bacteria, nitrate, hardness and pH. Tests for iron, sulfates and chloride should be done every three to five years. If you are expecting a baby in your home you should test for nitrate at the beginning of the pregnancy. Depending on the test results, you may wish to test again before bringing the baby home and during the baby's first six months.

Even if you have a public water supply your water should be tested for total coliform bacteria if you make any changes in your plumbing or water treatment system which could introduce a contaminant. Before buying a new house have the water tested for bacteria and nitrate to insure its quality. Lending agencies often require the bacteria test before approving a loan.

If you have an old or shallow well, it is especially important to test your water regularly. Older methods of well construction, and the well's location in relation to septic or livestock facilities on many farms, makes older and shallow wells prone to contamination.

You should test for bacteria if your well head becomes flooded or submerged. Following a chemical spill or leak within 500 feet of your well, test your water for possible contamination. Also test your water supply if your neighbors have found contamination. Report unknown contamination or objectionable taste, odor or color in a private well to: Department of Public Health.


Discuss your water problems with your county Health Department or water testing lab. After contacting the lab your next step will be to take the sample. Follow the instructions from the lab closely. Keep a record of the test results. The records will show any change in your water quality you may not have noticed. Records are also necessary if you need to prove an outside activity, such as a spill or leak, affected your water supply.

Home screening tests

Currently on the market are screening tests to conduct various water tests in your home, such as tests for hardness, iron or nitrate. Many public agencies also conduct screening programs as a public service. Keep in mind these tests are a simplified version of the tests conducted by a lab. The results do not indicate if your water is safe to drink, only whether your sample contains the tested contaminant and the approximate level. These screening tests serve as useful tools for indicating if further testing is needed. If the results are positive, you should follow up with a test from a lab.

For Further Information: For further information on water testing or suspected contamination in your area, contact your local Health Department or county Cooperative Extension office.


This information comes from Purdue Extension bulletin WQ4, Why Test Your Water?

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This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.

MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

This information.was reviewed as of June 2008.  For more information about the contents please contact for webpage problems .