Draw a glass of water from the tap. Examine it closely. Hold it up to the light. Sniff it. And, finally, take a drink of it. On the basis of your examination, are you in a position to tell much about this water?
Such sensory tests cannot go far in analyzing water. The look, taste, and smell of water often give no clues as to the types and amounts of some contaminants. Some contaminants, of course, are obvious. Your eyes will quickly tell you when there is a significant amount of sediment in the water. And your nose will not fool you when there is hydrogen sulfide present. Likewise, algae, industrial wastes, and certain other contaminants will also give water distinctively unpleasant tastes. Such contaminants as calcium, magnesium, fluorides, nitrate nitrogen, ferrous iron, and free oxygen provide indicators that they are present in water. Actually, it is probably only through their after-effects that we know for sure that certain raw water contains these troublesome contaminants. We would have no way of knowing the quantities.
Even the presence of harmful bacteria may go completely unnoticed. In fact, if a given family has built up immunity to certain disease-producing bacteria in the water, it is possible they may never suffer any ill effects from drinking it. Unfortunately, guests in the home may not enjoy such immunity. Thus, there is the distinct possibility of their becoming ill after drinking such contaminated water. The best way to determine the kinds and amounts of various contaminants in the water is by means of laboratory analysis. Such analysis may be either physical, microbiological, or chemical. Where the homeowner maintains his own water system, he is well advised to have periodic bacteriological tests run. Such tests can assure him that the water is safe to drink, though admittedly a source could be contaminated at any time.
Municipal water systems make regular analyses of their water supplies, the larger the system, the more frequent the tests. The program in each city conforms to EPA Drinking Water Regulations.
While there are no controls requiring periodic bacteriological tests over private water systems, wise owners of private water systems do have such tests run on their drinking water at least once a year. A bacteriological test of a water sample will show the possible presence of disease organisms. A report will normally indicate whether the water is potable or not from a bacterial standpoint. Such tests may be run at no cost or for a small fee. Generally, any state or city health department has the facilities for running the tests.
Chemical analyses are run far less frequently. Indeed, the average homeowner may consider having a chemical analysis only in the event the notes a change in the water supply ... a strange taste or odor, an unusual color, etc. Again, he may feel compelled to have an analysis performed in considering the purchase of a water softener or some type of filter, for example. Limited mineral analysis can be run to provide a spot check on certain contaminants. A complete analysis can be made so as to provide a thorough "personality profile" on a water supply. An independent water laboratory can perform such analyses. In many cases, water conditioning equipment manufacturers are equipped to run the tests.
A simple test you can do by yourself at home for water hardness. Take a small bottle or jar (about 2-ounce capacity) and put in it one ounce of water. Add liquid soap (use a tincture of green soap Lilly No.100 or U.S.P. XV, which can be obtained at any drug store), one drop at a time. After each drop, cap the bottle and shake. Continue to add soap until a good quantity of lasting suds has been formed. The number of drops of soap required to form suds will indicate the approximate hardness of the water in grains per gallon. (One drop equals one grain.) If more than one drop of soap is added, the water is considered hard. Soft water will form suds after the addition of one drop of soap.
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