DRINKING
WATER STANDARDS

pH                                                                          5.0 - 9.0                                                   SAFE

TOTAL DISSOLVED                                          30 - 900 ppm                                          SAFE
SOLIDS

ELECTRICAL                                                       0.05 - 1.5 mmho/cm                               SAFE
CONDUCTIVITY

MAGNESIUM                                                      Less than 400 ppm Mg                        SAFE

TOTAL                                                                  0 – 75 ppm CaCO3                                SOFT WATER
HARDNESS                                                          75 – 150 ppm CaCO3                            MODERATLY HARD WATER
                                                                                150 – 300 ppm CaCO3                          HARD WATER
                                                                                300 + ppm CaCO3                                 VERY HARD WATER

SULFATE-SULFUR                                             Less than 83 ppm SO4-S                     DESIRABLE

CHLORIDE                                                            Less than 250 ppm Cl                          SAFE

TOTAL ALKALINITY                                        Less than 400 ppm CaCO3                  NO PROBLEM

IRON                                                                      Less than 0.3 ppm Fe                           DESIRABLE

MANGANESE                                                      Less than 0.05 ppm Mn                       DESIRABLE

COPPER                                                                 Less than 1.0 ppm Cu                          DESIRABLE

FLUORIDE                                                            0.75 – 1.50 ppm F                                  SAFE

NITRATE-NITROGEN                                        Less than 10 ppm NO3-N                    SAFE

If the nitrate level is above 10 ppm, there is cause for concern. A safe alternate source of water should be found for infants under six months of age and pregnant mothers (because of the danger of prenatal methemoglobinemia). A nitrate-nitrogen level over 10 ppm is less critical if only adults and older children will be drinking the water. You may wish to consult with you personal physician or a health professional before deciding on a course of action. Boiling will not reduce the nitrate levels in water.

COLIFORM                                       No Colonies per 100 ml                 SAFE
BACTERIA                                                           See below for further details on Bacteria

(ppm is the same as mg/L)

Drinking Water
Bacteriological Testing

The test routinely performed on drinking water to determine water purity is the total coliform analysis. Coliform bacteria are associated with contamination from the intestinal tract of warm-blooded animals.When these bacteria are present in water, they may cause vomiting and /or diarrhea. Due to this association, the Environmental Protection Agency has designated total coliform bacteria as a standard that is used to determine water purity. Non-coliform bacteria may also be present in water, but no sanitary significance or limits have been placed on this group at this time.It should be pointed out that a water sample contaminated with coliform bacteria is not necessarily unsafe for consumption. It is only when the coliform bacteria contain pathogenic bacteria (disease causing organisms) that the supply is unsafe. The presence of coliform bacteria indicates that the bacteria has been introduced into the water supply by 1) human contamination, such as, an individual performing maintenance on the supply; 2) poor well construction, allowing surface water to seep into the well; or 3) the aquifer is contaminated.  The laboratory does not distinguish between pathogenic and non-pathogenic bacteria, therefore all samples contaminated with coliform bacteria should be considered as unsafe for consumption.

Coliform Test report Methods
            

A,  Coliform Density per 100 ml

The coliform density per 100 ml must be 0.  Samples that contain any coliform bacteria per 100 ml do not meet the bacteriological standard for purity.  Ideally coliform bacteria must be absent in a 100 ml sample.

B.  (TNC) Too Numerous to Count

“Too numerous to count” describes a condition in which excessive numbers of non-coliform bacteria prevent the accurate determination of coliform bacteria.  Due to the excessive numbers of non-coliform bacteria present, it cannot be determined whether this sample meets the bacteriological standard for purity.A replacement sample is requested.