Livingston County Michigan Health Department - Understanding Your Water Test Results

[Junk to delete/ehnav.htm]

Bacteriological Analysis

Bacteriological analysis of water is for total coliform. There are four methods which may be used by laboratories for the analysis of drinking water for total coliform.

Depending on the method used, the sample analysis could be completed within 24 to 96 hours. These coliform organisms are common inhabitants of the intestinal tracts of humans and other warm blooded animals.

They can be found in topsoil, sewage, ponds, lakes, and other surface waters. The presence of these organisms in your water supply may mean that your drinking water is not properly protected from contamination, which may include human disease causing organisms. Coliform organisms themselves usually will not cause disease.

Results of Coliform Analysis

ND	"Not Detected" - No coliform organisms were detected in the water sample. The sample meets the state drinking water standard for bacteriological quality at the time of sampling. (Similar results may be reported as negative, absent, or zero, "0".)
OG	"Overgrowth" - No coliform organisms were found, but bacteria in the water supply have grown on the filter to the extent they may have interfered with the identification of coliform organisms. These results cannot be directly interpreted as representing either a safe or contaminated water supply, and the water supply warrants further investigation. (Similar results may be reported as interference, or "INT".)
POS	"Positive" - Coliform organisms were present in the water sample. Safety can't be assured. Collection of a resample to confirm the original result is recommended. An investigation into the cause of the problem by a qualified individual is advised. (Similar results may be reported as present or any number from 1 to 200.)
FC-POS	"Fecal coliform detected" - Fecal coliform organisms were detected in the water sample. Fecal organisms are found in the intestines of warm blooded animals, and, as such, their presence in a water supply is considered an indication of sewage contamination. Precautions are recommended in the use of the water supply.
Any Code	"Sample more than 30 hours old when received at the laboratory" - Coliform organisms may die between sample collection and testing, or other bacteria may grow causing interference. If the time between sample collection and testing exceeds the above time limits, test results should not be considered accurate, and a check sample is recommended.

Partial Chemical Analysis

The Michigan Department of Public Health laboratory analyzes drinking water for eight parameters in a routine testing procedure referred to as a partial chemical analysis. Below is a table of these parameters and associated problems.

Except for fluoride and nitrate, the levels listed below are general guidelines. State drinking water standards have been established and are listed for these two chemicals.

Test results are reported in milligrams per liter (mg/l) for all parameters.

TEST RESULTS IN Milligrams PER LITER (MG/L)
Test	Excellent	Satisfactory	Objectionable	Problem
Iron	0-0.2	0.2-0.5	Over 0.5	Staining, turbidity taste, odor
Sodium	0-20	20-250	Over 250	Taste, special diets may require water of low sodium content
Nitrate (N)	0	1-10	Over 10 (State drinking water standard is 10)	Nitrate poisoning-especially infaNitrate/td>
Nitrite	0	0-1	Over 1	Nitrite poisoning-especially infants
Hardness (CaCo3)	25-100	100-250	Over 250 or less than 25	Scaling of water fixtures, soap scum at high levels; corrosion at low levels
Sulfate	0-50	50-250	Over 250	Laxative taste, odor, scaling in boilers, heat exchangers
Chloride	0-20	20-250	Over 250	Taste; corrosion
Fluoride	1.0-1.2	0.7-2.0 or 1.7-2.4	Over 4.0 (State drinking water standard is 4)	Low levels are beneficial in preventing tooth decay. High levels may cause mottling of teeth

Livingston County Department of Public Health
email: Public Health Department

Public Health Phone 517.546.9850 FAX 517.546.6995
Environmental Health Phone 517.546.9858 FAX 517.546.9853