Sampling

A good water testing laboratory should provide you with clean containers and clear instructions on how to collect your tap water sample. Some laboratories will package and ship the sample collection bottles to you. After sample collection you return the samples in the same shipping container. In order to prevent biased test results, it is essential that you follow the water sample collection, preservation, and shipment instructions carefully. The sample should be taken at the tap, but if you have a water softener or pressure tank, a more representative sample should be collected before your well water enters the storage tank.

To locate an Arizona state certified laboratory, contact the Arizona Department of Health Services (ADHS) Bureau of State Laboratory Services for a list of certified water testing laboratories in Arizona (602-364-0728). Water testing laboratories must comply with state and federal guidelines by using EPA 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.

Water Testing Costs

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. For example, testing for hardness, TDS, and pH may cost about $50. Testing for lead or nitrate may cost about $30. However, testing for all possible individual pollutants can cost more than $2,500 per sample.

Laboratory Test Results

After you receive the analytical results the laboratory will likely respond to your telephoned questions. Most laboratories include an explanation of their acronyms included with the final report, for example, ‘BDL’ means that if a constituent was present in your sample, it was below the laboratory analytical detection limit. Most reports list the analytical detection limit, the MCL, and the result of your water analysis. Results should always be lower than the MCL (or SMCL). If your results are not at or below the MCL, your water quality may be a health hazard.

You may wish to contact a water quality expert and/or water treatment vender to assess which water quality parameters can be addressed with treatment options.

Doing Your Own Testing: Water Testing Kits

Consumers have at their disposal numerous types of disposable water testing kits that can be readily purchased from internet companies. Most of these kits rely on color changes in either paper strips or liquid solutions to determine an approximate range of concentrations in the water sample. These test-strip methods rely on a characteristic color change when a water contaminant is exposed to a specific chemical reagent. Most testing kits provide a color scale used to estimate the level of a contaminant based on the color intensity. These kits provide complete instructions and easy to follow steps. Deviating from them usually results in erroneous data. Other kits may only provide a “negative’ or “positive result” which is of limted use since you still won’t know if the concentration is above the MCL. Testing kits have several limitations when compared to many EPA approved methods used in certified laboratories, these include:

• High contaminant detection limits (may only detect contaminants that exceed drinking water standards).
• Limited or narrow contaminant detection range.
• Testing method and/or shortcuts used may not be EPA approved.
• Poor or insufficient precision and accuracy.
• Results may be influenced by the presence of other water constituents, such as dissolved iron.

On the other hand, these kits can serve the consumer well when:

• Only kits from reputable companies that offer a certification or approval for use from the EPA are used.
• Used for routine verification of water quality in conjunction with less frequent tests done by a certified laboratory to verify these “home” tests.
• Needed to save money and time and provide peace of mind, but only when used properly and when regularly verified by certified laboratories.
• Used as a means by which to routinely monitor your well and to notify you when more accurate testing may be required.

The price of home testing water analysis kits ranges from a few dollars to thousands of dollars, depending on the degree of precision and accuracy, numbers of tests and automation that the consumer wants. Since most tests are based on color, results may be read directly using color strips, or sophisticated portable colorimeters that can cost over a thousand dollars. This costly investment may be worth it, depending on the number or samples, types of tests and data quality desired by the consumer.

The savvy consumer should use kits that are EPA certified for water testing with a level of complexity that they are comfortable with. Examples of independent companies that sell water testing kits include Hach®, Lamotte®, EM Quant®, WaterWorks®, and resellers like Benmeadows® (no endorsements implied).