Q & A - Water Quality Testing for Private Well Owners

• What are my responsibilities as a private well owner?
• Where can I get my water tested?
• What should I have my water tested for?
• What are coliform bacteria?
• How often should I have my water tested?
• How do I collect a water sample?
• How do interpret the water analysis results?
• How do I treat my water?
• Other helpful extension publications and web pages

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	Symptoms	Water test to consider
Appearance	Frothy, foamy	Detergents
Appearance	Black flakes	Manganese
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:

• If there is any noticeable change in water color, odor or taste. However, don't depend on changes in color, odor or taste to indicate bacterial contamination. Water contaminated with bacteria will often smell, look, and taste normal.
• If flooding occurs near a well or the wellhead has been flooded for any reason.
• If anyone who has consumed the water becomes ill from a suspected water-borne disease.
• If there has been any maintenance of the water system.
• Whenever the water or well system has been contaminated or is suspected to have been contaminated by human or animal waste.
• Any time a pregnant woman, woman anticipating pregnancy or infant under the age of six months becomes a water user, test for nitrate contamination.

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:

• Use a clean plastic container - rinse it three times with the well water before you collect the actual sample.
• Wash your hands prior to sampling and do not touch the inside of the container or lid.
• Let the water flow for about five minutes before sampling.
• Do not draw water from an aerated faucet or a swing arm faucet.
• Label the sample with permanent marker. Include your name, telephone number, and the date, time, and place where the sample was taken.

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.

Contaminant	Potential health effect	Numeric standard (mg/l)
Coliform bacteria	Useful as an indicator that other, potentially harmful bacteria may be present	Present
E. Coli bacteria	Gastrointestinal illness (e.g., diarrhea, vomiting, cramps)	Present
Antimony (An)	Increase in blood cholesterol, decrease in blood glucose.	0.006
Arsenic (As)	Increased risk of cancer, skin damage, circulatory problems	0.2
Barium (Ba)	Increase in blood pressure	2.0
Beryllium (Be)	Intestinal lesions
Cadmium (Cd)	Kidney damage	0.005
Chromium (Cr)	Allergic dermatitis (occurs after multiple years)	0.1
Copper (Cu)	Gastrointestinal distress; long term exposure could lead to liver or kidney damage.	1.3
Fluoride (F)	Bone disease (pain and tenderness), children may get mottled teeth.	4.0
Lead (Pb)	Delays physical or mental development in infants and children, kidney problems and high blood pressure in adults.	0.015
Nitrates	Methoglobinemia "blue baby syndrome" in infants under six months - life threatening without immediate attention	10
Selenium	Hair or fingernail loss, numbness in fingers or toes, circulatory problems	0.05

Table 3. Secondary drinking water contaminants.

Contaminant	Effect	Numeric standard (mg/l)
Aluminum (Al)	Colored water	0.2
Chloride (Cl)	Salty taste	250
Copper (Cu)	Metallic taste, blue green staining	1.3
Fluoride (F)	Tooth discoloration	2.0
Iron (Fe)	Rusty color, sediment, metallic taste, reddish or orange staining	0.3
Manganese (Mn)	Black to brown color, black staining, bitter metallic taste	0.05
pH	If the pH is low - bitter, metallic taste, corrosion. If the pH is high - slippery feel, soda taste, deposits	6.5-8.5 (on a pH scale)
Sulfate	Salty taste	250
TDS	Hardness, deposits, colored water, staining, salty taste	500
Zinc (Zn)	Metallic taste	5.0

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.

Symptom	Effect	Cause	Treatment
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 orderpubs@montana.edu

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.

Home Page