What's Wrong With My Water? Choosing the Right Test

(WQ1352, Revised Feb. 2022)
Publication File:

This publication is intended to help the public identify water quality problems based on appearance, color, odor or taste and guide them towards the proper water treatment method to correct the problem.

Lead Author
Lead Author:
Reviewed by Tom Scherer, Ph.D., Extension Agricultural Engineer, North Dakota State University
Other Authors

This publication was authored by Roxanne Johnson, former water quality associate

Web only
Publication Sections

Choosing the Right Test

Who is Responsible?

Households using municipal or rural water supplies can depend on the utility to follow Environmental Protection Agency (EPA) guidelines for maximum levels of contaminants. An annual report is distributed to the users.

Private well owners are not monitored by government agencies. This means the owner must take responsibility for the condition of the system.

Routine testing establishes a water-quality record. If a contaminant problem develops, correlating the cause is easier if you keep a water-quality record.

What’s in Your Water?

Water is never just pure hydrogen and oxygen. Water naturally contains minerals and microorganisms from the rocks, soil and air in which it comes in contact. Human activities add many more substances to water. Some, such as bacteria, come from waste products of people and animals. Others, such as gasoline and industrial solvents, are synthetic chemicals, made and used for special purposes. Still other materials, such as nitrate and salt, occur naturally, but human activities can increase their concentrations in the environment. Which of the many potential drinking water contaminants should you be concerned about?

Reasons to Test Your Private Well

  • Your well is new or recently serviced
  • The area around the wellhead has been flooded or submerged
  • Back-siphoning has occurred
  • You have used, mixed or spilled pesticides near the well
  • You have a heating oil tank or underground fuel tank near the well that has leaked
  • You are pregnant, are planning a pregnancy or have an infant less than 6 months old
  • Your or your neighbor’s septic system absorption field is close to the well (within 100 feet)

Annual Baseline Testing

  • Coliform (bacteria)
  • Nitrate/Nitrite (forms of nitrogen)
  • Total Dissolved Solids (salts)
  • pH
  • Any constituents that were at or near maximum safe drinking water limit standards in
    previous tests

Every Five Years

  • The above tests
  • A complete water chemistry

Keep copies of ALL results so you can track changes in your water quality through time.

Water Problem Identification

Problem or Concern


Water Test to Consider


Frothy, foamy



Black flakes



Brown, yellow or reddish


Odor or taste

Rotten egg

Hydrogen sulfide

Odor or taste


pH, iron, zinc, copper, lead

Odor or taste


Total dissolved solids, chloride, sodium, sulfates

Odor or taste

Septic, musty or earthy

Coliform bacteria, iron

Odor or taste


Surfactants, detergents

Odor or taste

Gasoline or oil

Hydrocarbon scan, volatile organic chemicals (VOCs)

Stains on fixtures or clothing

Red or brown


Stains on fixtures or clothing



Stains on fixtures or clothing

Green or blue


Stains on fixtures or clothing

Reddish-brown slime

Iron bacteria

Stains on fixtures or clothing

White deposits, soap scum

Hardness (calcium and magnesium)

Discoloration of children’s teeth



Gastrointestinal illness


Coliform bacteria, sulfates, giardia

Deposits on sinks and plumbing pipes

Pitting of fixtures or corrosion

Corrosivity, pH, lead, zinc, manganese, copper, iron, sulfates, chloride

Leaking fuel tank


Hydrocarbon scan, VOCs

Road salt


Total dissolved solids, pH, VOCs, heavy metals

Sewage sludge applied to fields


Coliform bacteria, nitrate, metals (lead, cadmium)

Septic system problems
(effluent coming to surface)


Coliform bacteria, nitrate, detergents, total dissolved solids, chloride, sodium, sulfates

Intensive agricultural nearby


Coliform bacteria, nitrate, pesticide scan, pH, total dissolved solid

How Do I Test My Water?

Contact a certified lab for questions concerning sampling. A list of certified water testing labs is included in WQ1341, Drinking Water Quality: Testing and Interpreting Your Results.

Bacterial Analysis

Most labs will provide a sterile collection container with instructions. This container may contain a chlorine inhibitor, so do not rinse the container prior to use.

Remove the aerator from the faucet if it has one. Sterilize the end of the faucet with a flame or douse with alcohol. Remove the bottle cap, taking care not to touch the inside of the cap or container.

To remove stagnant water from the system, run the water for at least 30 seconds and then fill the bottle to the line indicated or near the top. Immediately replace the bottle cap and secure transportation as soon as possible because coliform samples should be analyzed within 36 hours of collection.

Chemical analysis

Well water

Pump the well for several minutes so the actual sample collected is from the groundwater source. 

common well head in the middle of green grass
Common well head for a 4-inch diameter casing with submersible pump.

Tap water

Run the tap fully open for 30 seconds before collecting the sample.

Rinse the container two to three times with the water being collected unless preservative has been added to the container to maintain sample integrity (iron and manganese).Lead testing requires the water sample to be taken after the water has been sitting undisturbed in pipes. Do not run water prior
to sampling.

Completely fill the container, leaving a small space for expansion of the liquid. Immediately replace the bottle cap.

Send the samples to the lab within 48 hours.

Good-quality (potable) drinking water is free from disease-causing organisms, harmful chemical substances and radioactive matter.

It tastes good, is aesthetically appealing and is free from objectionable color or odor.

Which water treatment system?

Selecting the appropriate water treatment system

  • Point-of-entry – Treats water as it enters the residence.
  • Point-of-use – Treats water at a single tap. All filtration units can be fitted for whole-house application; however, expense may be a factor to consider.


Treatment and Comments


Tea coloring formed during the decomposition of vegetation. pH more than 6.0 – anion exchange. pH less than 5.0 – activated carbon filter


Water softener (cationic ion exchange) or iron/manganese filtration

Odor: grassy or musty, chlorine, rotten egg or hydrogen sulfide –
smell dissipates after 15 to 30 seconds.

Activated carbon filtration

Oxidizing filter

Chlorination or aeration followed by filtration

Manganese greensand, chlorination, aeration

Odor: chemical

Stop chemical seepage, use activated carbon.


High or low pH can affect the efficiency of water treatment systems. Neutralizer filter


Shock chlorination followed by repeated testing should be done to determine if this is a one-time event from surface water contamination or if aquifers have been polluted. Ultraviolet disinfection may be used on a more permanent basis; however, sourcing the contamination needs to be a priority. Fecal coliform and E. coli, while not pathogens, are indicators of disease-causing microbes and water should not be used for drinking. Boiling water will kill coliform.


No health effects. Can be addressed by removing the following: soil erosion, waste discharge, urban runoff; eroding stream banks; large numbers of bottom feeders (such as carp), which stir up bottom sediments; and excessive algal growth.

Activated carbon filtration


Salty taste and with high levels, a laxative effect. Reverse osmosis, distillation


Added to municipal water. Children under 9 should not drink water that has more than 2 mg/L of fluoride. Reverse osmosis, activated alumina or distillation

Nitrate, Nitrites, Nitrate (as N)

High nitrate may cause methemoglobinema (blue baby) in infants who drink water or formula made from water with high levels. Health concerns with long-term use for adults. Reverse osmosis, distillation


A known carcinogen and associated with many health risks. Treatment is dependent on level of contamination. Chlorinate to change from A3 to A5 form, remove with filtration, distillation, reverse osmosis (A3 removal), alumina, anion exchange


Generally associated with high pH values, hardness and excess dissolved solids.

Reverse osmosis or tank media


Gastrointestinal distress to liver or kidney damage, depending on exposure time. Corrosion control including the addition of Poly 4 in crystal form to coat the pipes within your home. Distillation, reverse osmosis


Water softener (cation exchange)

Iron Ferrous (clear and colorless when drawn)

Ferric (ferrous water when exposed to air converts to reddish brown)

Metallic taste. Rust stains in toilets, plumbing fixtures, tableware and laundry.

Water softener or oxidizing filter system

Iron bacteria (red, orange,
yellow water) 

Slime on well screens, pipes and plumbing fixtures. Smells of fuel oil, cucumber or sewage. Shock chlorination

Manganese (black)

Reddish-brown water, staining of plumbing fixtures and laundry. Off-taste and odor. Reverse osmosis or chlorination followed by oxidizing filter


The pipes in your home are the likely source of high lead levels. Use only thoroughly flushed water from the cold tap for consumption. Reverse osmosis, distillation


Use potassium pellets instead of sodium softener pellets. Restrict drinking water from this source. Reverse osmosis, distillation


May have a laxative effect on people unaccustomed to the water. Reverse osmosis, distillation, anion exchange

Total Dissolved Salts (TDS)

Adverse taste. Deteriorates plumbing and appliances. Reverse osmosis, distillation