What are my responsibilities as a private well owner?
Government or municipal agencies do not monitor water quality in private wells. This means that the well owner is responsible for the quality and safety of the well water. Routine testing for a few of the most common contaminants is highly recommended. Even if you currently have a safe water supply, regular testing can be valuable because it establishes a record of water quality.
All water from natural sources contains dissolved substances. These substances are referred to as primary contaminants when the amounts present are at harmful or problematic levels. Primary contaminants can be biological such as bacteria or viruses; inorganic chemicals such as lead, nitrate or sulfate; and organic chemicals such as insecticides, herbicides, fuel and solvents. Secondary contaminants are not a health risk, but can make water less desirable for domestic use. Secondary contaminants include calcium and magnesium (hardness), iron, manganese, and hydrogen sulfide, odor, taste, and color.
Where can I get my water tested?
Many commercial laboratories in Montana have the facilities to test water. Prices vary but will often be competitive with state labs. When obtaining laboratory services for water testing, look for three things: 1) guidance with collecting samples, 2) analytical services available, and 3) assistance with interpretation of results. An online directory of certified laboratories for Montana and EPA Region VIII (Colorado, Montana, Wyoming, Utah, South Dakota, and North Dakota) is available.
The State of Montana requires certified labs to adhere to the State of Montana Drinking Water Certification requirements which have been adapted from the EPA Manual for the Certification of Laboratories Analyzing Drinking Water. Certified labs in Montana are required to use EPA-approved analytical methods, compile a quality assurance manual in accordance with EPA guidelines, schedule an on-site inspection of laboratory facilities, and perform the accurate analysis of two (EPA) proficiency evaluation samples per year.
What should I have my water tested for?
There is no single test to determine the quality of drinking water and no single test can answer all the questions. It would become costly and, in most cases, unnecessary to test for all possible contaminants. The following table provides guidelines for water testing. It is important to note that an expert should be consulted if you suspect any contaminant that could present an immediate or long-term heath risk.
|Table 1. Selecting appropriate drinking water quality tests.|
Problem or concern
Water test to consider
|Appearance||Brown, yellow, or reddish||Iron|
|Odor or taste||Rotten egg||Hydrogen sulfide|
|Odor or taste||Metallic||pH, iron, zinc, copper, lead|
|Odor or taste||Salty||Total dissolved solids, chloride, sodium, sulfates|
|Odor or taste||Septic, musty, or earthy||Coliform bacteria, iron|
|Odor or taste||Soapy||Surfactants, detergents|
|Odor or taste||Gasoline or oil||Hydrocarbon scan, volatile organic chemicals (VOC's)|
|Stains on fixtures or clothing||Red or brown||Iron|
|Stains on fixtures or clothing||Black||Manganese|
|Stains on fixtures or clothing||Green or blue||Copper|
|Stains on fixtures or clothing||Reddish-browh slime||Iron bacteria|
|Stains on fixtures or clothing||White deposits, soap scum||Hardness (calcium and magnesium)|
|Uses and symptoms||Discoloration of children's teeth||Fluoride|
|Uses and symptoms||Gastrointestinal illness||Coliform bacteria, sulfates, giardia|
|Uses and symptoms||Water supply used for infants less than six months old, pregnant or nursing women, or elderly with genetically impaired enzyme system||Nitrates|
|Corrosion||Pitting of plumbing fixtures and deposits on sinks and plumbing pipes.||Corrosivity, pH, lead, zinc, manganese, copper, iron, sulfates, chloride|
|If you suspect or observe:||Leaking fuel tank||Hydrocarbon scan, VOC's|
|If you suspect or observe:||Road salt||Total dissolved solids, pH, VOC's, heavy metals|
|If you suspect or observe:||Landfills||Total dissolved solids, pH, VOC's, heavy metals|
|If you suspect or observe:||Sludge utilization||Coliform bacteria, nitrate, metals (lead, cadmium)|
|If you suspect or observe:||Septic system failure||Coliform bacteria, nitrate, detergents, total dissolved solids, chloride, sodium, sulfates|
|If you suspect or observe:||Intensive agricultural use||Coliform bacteria, nitrate, pesticide scan, pH, total dissolved solids|
|Table adapted from DeLynn, H. and Skipton, S. 1998. Testing for Drinking Water Quality, G89-907-A.|
What are coliform bacteria?
Coliform bacteria are organisms found in soil or vegetation and in the intestinal tract of warm-blooded animals. Coliform bacteria serve as an indicator of the contamination of water and possible presence of intestinal parasites and pathogens. Lab tests for coliform bacteria are relatively inexpensive or can be performed at home using the Coliscan Easygel method. If detected, coliform bacteria indicate that more dangerous pathogens, such as E. Coli, may be present. Therefore, by observing coliform bacteria, the absence or presence of many pathogenic bacteria can be indicated.
How often should I have my water tested?
Generally, private water supplies should be tested for nitrate and bacterial contamination annually. Otherwise, drinking water should be tested if:
Coliform bacteria are most likely to be found during wet weather, when runoff and excess soil moisture carry contaminants into shallow groundwater sources or through well defects. To assess the year-round safety of your drinking water, test for bacteria in the late spring or early summer. Testing during extremely dry weather or when the ground is frozen may not indicate the presence of bacteria because the lack of moisture migration through the soil profile reduces the likelihood of finding high contaminant levels in wells.
Test for other substances when specific contamination is suspected (see Table 1). This might be the result of a spill, backflow, or use of harmful products in close proximity to well or other such event. Any noticeable change in water taste, color or smell signals the need for testing. Collect a water sample at a time when a contaminant is most likely to be present.
How do I collect a water sample? Laboratories typically provide clean containers and detailed instructions about sampling procedures. The lab should be contacted before the water sample is collected to insure the sample is taken properly. If this is not provided, follow these steps when taking a well water sample:
For best results, refrigerate water samples (DO NOT FREEZE) and have them analyzed within 30 hours of the initial collection. Water samples should be shipped within one day of sampling and on a Monday, Tuesday, or Wednesday to make sure that the sample arrives at the lab in time.
How do I interpret the results?
The Safe Drinking Water Act requires the U.S. Environmental Protection Agency (EPA) to set limits or standards for contaminant concentrations that may pose health risks. There are two categories of drinking water standards: primary (maximum contaminant level) and secondary (secondary maximum contaminant level). Primary standards (Table 2) are the highest allowable concentrations of contaminants based on health considerations. Secondary standards (Table 3) regulate contaminants that cause offensive taste, odor, color, corrosion, foaming, and staining or other offensive or non-desirable conditions which are not necessarily harmful to human health. Although private drinking water supplies are the responsibility of the well owner, these standards can serve as a guide to ensure safe and enjoyable drinking water for private well water systems.
The Montana State University water quality web page provides an interactive lab analysis to help private well owners understand their lab results. Lab results can be entered directly onto the web page and responses about water quality and water treatment are generated.
|Table 2. Primary drinking water contaminants.|
Potential health effect
Numeric standard (mg/l)
|Coliform bacteria||Useful as an indicator that other, potentially harmful bacteria may be present||
|E. Coli bacteria||Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)||
|Antimony (An)||Increase in blood cholesterol, decrease in blood glucose.||
|Arsenic (As)||Increased risk of cancer, skin damage, circulatory problems||
|Barium (Ba)||Increase in blood pressure||
|Beryllium (Be)||Intestinal lesions|
|Cadmium (Cd)||Kidney damage||
|Chromium (Cr)||Allergic dermatitis (occurs after multiple years)||
|Copper (Cu)||Gastrointestinal distress; long term exposure could lead to liver or kidney damage.||
|Fluoride (F)||Bone disease (pain and tenderness), children may get mottled teeth.||
|Lead (Pb)||Delays physical or mental development in infants and children, kidney problems and high blood pressure in adults.||
|Nitrates||Methoglobinemia "blue baby syndrome" in infants under six months - life threatening without immediate attention||
|Selenium||Hair or fingernail loss, numbness in fingers or toes, circulatory problems||
|Table 3. Secondary drinking water contaminants.|
Numeric standard (mg/l)
|Aluminum (Al)||Colored water||
|Chloride (Cl)||Salty taste||
|Copper (Cu)||Metallic taste, blue green staining||
|Fluoride (F)||Tooth discoloration||
|Iron (Fe)||Rusty color, sediment, metallic taste, reddish or orange staining||
|Manganese (Mn)||Black to brown color, black staining, bitter metallic taste||
|pH||If the pH is low - bitter, metallic taste, corrosion. If the pH is high - slippery feel, soda taste, deposits||
(on a pH scale)
|TDS||Hardness, deposits, colored water, staining, salty taste||
|Zinc (Zn)||Metallic taste||
How do I treat my water?
Water treatment refers to systems that reduce harmful contaminants in the water and therefore deal with health and safety of the water. High levels of coliform, nitrates, arsenic, lead and pesticides are examples of harmful contaminants that must be treated for water to be safe to drink. Household water treatment processes for common water quality problems are listed in Table 4.
|Table 4. Some common water quality problems, causes and cures.|
|Hardness||Soap curd and lime scum in bath, white scale in pipes||Excessive magnesium and calcium salts||Water softener (cation exchange)|
|Grittiness||Feels abrasive when washing, leaves a residual in bath||Silt passing through well screen||Sand trap, membrane filtration|
|Odor||Grassy or musty||Organic matter||Activated carbon|
|Odor||Chlorine||Excessive chlorination||Activated carbon|
|Odor||Chemical (phenol)||Industrial waste seeping into water supply||Stop seepage, activated carbon|
|Odor||Rotten egg||Hydrogen sulfide||Manganese greensand, chlorination, aeration|
|Taste||Salty or brackish||High sodium or magnesium content||Cation/anion exchange, reverse osmosis, distillation|
|Taste||Metallic||Low pH||Acid neutralization|
|Taste||Metallic||High iron content||Oxidation and filtration|
|Stainless steel corrosion||Blackening or pitting of sinks and dishwashers||Excessive chloride content||Alternative materials, partial reverse osmosis|
|Turbidity||Mud, silt, and/or clay||Suspended matter in water supply||Filtration|
|Acid water||Green stains on plumbing fixtures||Low pH reacting with copper and brass piping and fittings||Acid neutralization|
|Red water||Stains dishes and laundry||Dissolved iron||Oxidation and filtration|
|Red water||Red sediment when water is left standing||Precipitated iron||Oxidation and filtration|
|Red water||Red color even after standing for 24 hours||Colloidal iron||Oxidation and filtration|
|Milky water||Cloudiness when drawn||Entrained air from faulty pump||Water should clear quickly|
|Milky water||Cloudiness when drawn||Sledge pickup in hot water heater||Clean heater periodicially|
|Milky water||Cloudiness when drawn||Methane gas||Aeration with proper venting (volatile gas)|
|Excess fluorides||Yellowish, mottled teeth in children||Excessive fluorides||Activated alumina, reverse osmosis, deinoization, distillation|
|Nitrates||No color, taste, or odor. Possible health hazard for infants.||Human or animal waste and/or fertilizers seeping into water supply.||Anionic ion exchange, reverse osmosis, distillation, deionization|
|Heavy metals||No color, taste, or odor signs. Possible health effects.||Industrial pollution, corrosion products.||Softening, deionization, reverse osmosis|
|Pesticides and herbicides||Chemical taste||Excessive agricultural spray applications.||Activated carbon|
|Radioactive contaminants||No color, taste or odor signs. Possible health risk.||Natural radium radioactivity, atmospheric fallout, nuclear waste.||Water softening, deionization, reverse osmosis.|
|Radioactive contaminants||No color, taste or odor signs. Possible health risk.||Radon gas||Aeration at faucet, carbon absorption|
|Source: Vogel, Micheal P., 1991, Household Drinking Water Protection and Treatment: Montana State University Extension Publication EB 102.|
Other helpful extension publications: Montana State Universtiy Extension Publications:
These publications can be accessed online or ordered:
|MSU Extension Publications
P.O. Box 172040
Bozeman, MT 59717-2040
or e-mail firstname.lastname@example.org
This fact sheet was compiled from the following resources:
DeLynn, H. and Skipton, S. 1998. Testing for Drinking Water Quality, G89-907-A.
Donaldson, S., Walker, M. Courtois, D. 2000 Water testing for Private Well Owners.
Manual for the Certification of Laboratories Analyzing Drinking Water, 1997, EPA 815-B-97-001.
Vogel, Micheal P. , 1991, Household Drinking Water Protection and Treatment: Montana State University Extension Publication EB 102.
Waskom, R.M., Davis, J.G, and Self, J.R. 2000. Selecting an Analytical Laboratory.