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Testing Your Water

Well Testing Schedule
Water Testing
Laboratory Test Results

Well Testing Schedule
Domestic wells should be tested annually for the presence of coliform bacteria, as an indicator of pathogens. More frequent testing is suggested if visual changes in the water quality are noticed or if unexplained health changes occur. The table below provides a schedule and list of analyses for testing. When water tests positive for pathogens, owners may choose to use shock chlorination to disinfect the well casing and household plumbing. This may not eliminate the contamination if it is found in the aquifer water itself. In that case, the owner should seek an alternate source of water or install a home water disinfection system.

Suggested Schedule:

Initial Tests*
Hardness, sodium, chloride, fluoride, sulfates, iron, manganese, arsenic, mercury lead, plus all tests listed below

Annual Tests (at a minimum)
Total coliform bacteria, TDS, pH, nitrate

Monthly Visual Inspection
Look for and note changes in:
• Turbidity (cloudiness, particulates)
• Color, taste, and odor**
• Health changes (reoccurring gastrointestinal problems)***

*Annual testing may not be needed, as these chemicals usually are naturally occurring and their concentrations do not change over time.
**Consider one or more of the initial tests.
***Annual testing should begin immediately.

Water Testing
Before purchasing or installing a water treatment system, test your water at the tap. Be aware that water testing is not an easy or inexpensive step. Laboratory fees for water quality analysis vary greatly from one parameter to another. In 2004, for example, testing for hardness, TDS, and pH may cost about $50. Testing for lead or nitrate may cost about $25. However, testing for all possible individual pollutants can cost more than $2,000 per sample.

If you suspect that your house plumbing may be contaminating your water, test your water at the tap for those contaminants that may be present. Carefully choose the list of contaminants to be tested with the assistance of a qualified water quality expert. See the table of water problems and suggested tests, and review the national drinking water standards.

A good water testing laboratory should provide you with clean containers and clear instructions on how to collect your tap water sample. In order to prevent biased test results, it is essential that you follow the water sample collection, preservation, and shipment instructions carefully. To locate an Arizona state certified laboratory, call the Arizona Department of Health Services (ADHS) Bureau of State Laboratory Services for a list of certified water testing laboratories in Arizona (602-255-3454).

Water testing laboratories must comply with state and federal guidelines by using USEPA approved methods of analysis. Guidelines for water testing are regularly published and updated by the EPA and are also listed in the Code of Federal Regulations, Title 40, part 136.

Laboratory Test Results

Water testing is serious business: Laboratory analyst at work.

photo by:
Janick Artiola

click to enlarge

Have the tests results explained to you by a qualified analyst or water quality expert. For example, terms such as "BDL" mean that a pollutant could not be detected below a certain value or detection limit. BDL values should be listed in the laboratory report and they should always be lower than the NPDWS and the NSDWS maximum contaminant level (MCL).

Determine which parameters have values above drinking water standards and which parameter you would like to lower in order to improve water quality. (Information below on health effects and likely sources is from the Agency for Toxic Substances and Disease Registry, its parent organization, Centers for Disease Control and Prevention, and the U.S. Environmental Protection Agency.)

Lab result Potential health effects Likely source Treatment options
Acidity low
(pH levels under 6.0 )
Minimal or no effects Natural, acid mine seepage; often together with copper, zinc, and/or lead Acid neutralizing filters (POE) or addition of alkaline chemicals such as lime
Alkalinity high
(pH levels over 8.5)
Health effects minimal except for dry skin. Some studies indicate slightly alkaline water is better for human health than is water that is acidic. Naturally occurring alkalis in the soil and ground and surface waters Addition of acid chemicals or reverse osmosis or distillation systems (POE or POU)
Arsenic Skin damage or problems with circulatory system; possible increased risk of cancer


Erosion of natural deposits; runoff from orchards and from glass and electronic production wastes Reverse osmosis or distillation systems (POU)
Cadmium Drinking water with very high levels severely irritates the stomach, leading to vomiting and diarrhea. Long-term exposure to lower levels of cadmium leads to a buildup of cadmium in the kidneys and possible kidney disease.
Found in natural ore deposits. Also from corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries
Reverse osmosis or distillation systems
Copper and zinc Ingesting high levels of copper can cause nausea, vomiting, and diarrhea. Long-term exposure can lead to liver or kidney damange. Large doses of zinc taken by mouth can cause stomach cramps, nausea, and vomiting. Taken longer, it can cause anemia and decrease the levels of HDL cholesterol.

Copper: corrosion of household plumbing systems and erosion of natural deposits

Zinc: Naturally occurring, and treatment additives

Acid neutralizing filters (POE) or addition of alkaline chemicals such as lime
Lead Infants and children: Delays in physical or mental development; children may show deficits in attention span and learning abilities

Adults: Kidney problems; high blood pressure

Corrosion of household plumbing systems, and naturally occurring Reverse osmosis or distillation systems (POU)
Mercury Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetuses. Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands
Reverse osmosis or distillation systems (POU)
Nitrate Methemoglobinemia, a blood disorder that primarily affects babies, is caused by having too much nitrate in the body, preventing blood from delivering oxygen efficiently to different parts of the body. As a result, the infant may have blueness around the mouth, hands, and feet. Without treatment and removal of nitrate from drinking water, the condition can worsen and affect breathing. Other signs of the syndrome include vomiting and diarrhea.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits
Reverse osmosis or distillation systems (POU)
Radon gas Exposure to high levels may result in an increased incidence of lung diseases, such as emphysema and pulmonary fibrosis. Several studies of individuals exposed over long periods have reported significant increases in early mortality due to cancer and nonneoplastic (noncancer) diseases. Exposure is principally through inhalation of the gas as it is released through showerheads and taps. Naturally occurring Regulated and controlled by water providers with aeration. Some activated carbon filters reduce it in tap water (POU).
Sodium high High sodium levels are harmless for most people, but can be dangerous for the elderly, people with high blood pressure, pregnant women, and people having difficulty in excreting sodium. Naturally occurring, brine intrusion/seepage Addition of acid chemicals or reverse osmosis or distillation systems (POE or POU)
TDS   "Total dissolved solids" refers to any minerals, salts, metals, cations, or anions dissolved in water and usually naturally occurring. Excessive dissolved solids make water brackish or otherwise unsuitable for drinking or industrial uses. More discussion of TDS in Arizona municipalities is available here. Reverse osmosis or distillation (POU)

See also the list of water problems for a more complete list of symptoms and treatment options.

Continue on to Water Treatment Options


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