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Northeast Laboratories, Inc.

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Potable Water


Berlin Office
129 Mill Street, Suite 11
Berlin, CT 06037
CT 860.828.9787 or 800.826.0105
outside CT 800.654.1230
fax 860.829.1050
Contact the Berlin Office

Interpretation of Connecticut Laboratory Results

Proper interpretation of laboratory results takes into account all analyses made as well as sanitary data concerning the source of supply before an evaluation of the sanitary quality of water is made.  No single chemical, bacteriological, or physical test serves the purpose.

The following list/limits*/**  are presented as a guideline only.




Maximum Contaminant
Level (MCL) * or
Recommended Range **






Alkalinity is a measure of alkaline substances such as hydroxides, carbonates, and bicarbonated with capacity for neutralizing acid.


(No Established Limits) **






Chlorides are an indicator of sewage pollution if found in concentrations higher than normal for the area.  Normal chloride concentrations vary with distance from bodies of salt water.


250 mg/L **





      (Bacteriological Test):

This test is made to detect organisms of the so-called coliform group, found mostly in the intestinal tract of man and other animals.  The presence of coliform indicates the possibility that disease-producing organisms may also be present in the water:


Absent = 0 per 100 mL *






Color may result from iron, manganese, humus, plankton, weeds, or industrial wastes.


15 Units  **






Copper is used in plumbing systems.  It is not very toxic, but does cause staining.


1.3 mg/L  (if 1st Draw)  **
1.0 mg/L  (if Running)   **





Detergents  (MBAS):

This test measures detergent concentration.


0.5 mg/L  **






A fluoride content of one milligram per liter has been found to reduce tooth decay.


4.0 mg/L  **
Recommended Optimum: 1 mg/L






Hardness is primarily a measure of calcium and magnesium in water and is related to the soap-consuming power of water.


150 mg/L  **





Iron and

The presence of these metals causes staining of fixtures.


Iron:  0.3 mg/L  **
Manganese:  0.5 mg/L  **






Lead is a metal formerly used in soldering joints in plumbing systems.  It is now prohibited, but many houses still have lead in their plumbing systems.  Lead can build up gradually in the body and can have effects on the brain and nervous system.


0.015 mg/L  (if 1st Draw)  **
0.05 mg/L  (if Running)      **





Nitrogen Constituents:

These may indicate sewage or other nitrogenous organic contamination.  Nitrate Nitrogen in excess of 10 mg/L is potentially dangerous, particularly for infant feeding. 


Nitrate: 10 mg/L as N  *
Nitrite: 1 mg/L as N *
Combined Limit (Nitrate
plus Nitrite):  10 mg/L as N *






Odor is a subjective evaluation of acceptability of the water.


Not to exceed a value of 2  **
   on a scale of 0 to 5





pH Value:

pH defines the hydrogen-ion concentration in water and represents the aggressiveness of the water toward pipes, etc. (a low pH being more corrosive).


6.4 to 10 Range  **






Residue is  the solid matter present in water.


500 mg/L  **






Note:  Persons with high blood pressure, hypertension, congestive heart disease or persons on a low salt diet should consult their physician before consuming a source with a high sodium level.


28 mg/L






This test measures the light scattering property of solids in water as compared to a standard clay suspension.


5 Units

*    State of Conn. MCL
          * *  No State of Conn. MCL established; --  Levels noted are USPHS (U.S. Public Health Service) recommendations.

                mg/L  =  Milligrams per Liter              N  =  Nitrogen              mL  =  Milliliters