Is Your Water Well Safe?

If you rely on a well as your water source, it's up to you to make sure your well construction is sound and that your drinking water and pipes are free of contaminants.


| July/August 1983



drilled well diagram

A drilled well. Every well should have an annular seal, a concrete slab, and a well casing that extends above the slab. 


ILLUSTRATION: MOTHER EARTH NEWS STAFF

Fresh, unpolluted water is essential to our survival. If you live in a rural area and use a well (whether it be new or old) it's up to you to check your water source frequently and to pay careful attention to its maintenance. Surface contamination—often undetectable to the senses of taste or smell—can occur quickly and without warning. Properly located and properly cared for, a water well will give long service, but if you don't know what you're doing, you can run into a pack of trouble!  

Well Construction Basics

Every well should have an annular (circular) seal, a concrete slab, and a well casing that extends above the slab. The annular seal should be at least 6 inches thick, completely enclosing the casing to a depth of at least 20 feet. The seal—made of cement, bentonite, or any other approved material—is an absolute must to prevent surface water contamination. Many old wells have been lined with brick. If those clay blocks are glazed and in good condition, they can be faced with an inch or so of cement to form a satisfactory seal. Unglazed brick, however, must be removed and a new seal must be installed. 

In many areas of the country, the natural water table is only a few feet below the soil surface. Where the water table is high, a well without adequate sealing is easily polluted by surface seepage. A new well with a new casing will be safe from such contamination for a while, but only until it develops the inevitable rust holes. In the long run, it's less expensive—and less frustrating—to go ahead and put in a good annular seal than to have to pull and replace the casing every time it develops a spot of rust. 

Before being put into use (or reuse), every well should be tested for minerals, chemicals (particularly nitrate), and bacteria. After the initial analysis, the well should be tested once every year. 

Mineral and Chemical Contamination

Calcium can't be removed satisfactorily, and the only way to avoid it is to switch to a different water source. Since the major hazard of this mineral is fouled pipes, though, you could try to get by with using the water only at the well head, but this would obviously entail considerable inconvenience. 

Iron contamination can range from mere unpleasantness to a downright impossible-to-deal-with nuisance. A potassium permanganate filter will remove mineral iron down to 2 parts per million (PPM), which is a satisfactory solution for coping with suspended particles. However, the problem of so-called "iron bacteria" is harder to deal with. (These organisms aren't detrimental to human health. Still, brown drinking water isn't high on anyone's list of refreshments.) Your best initial recourse may be to put in a new pump that's been pretreated with full-strength swimming pool chlorine. And be sure to flush clean all the tools used in removing the old pump, because iron bacteria can adhere to almost anything, including your hands! If the problem persists in spite of the pump change and chlorine flushing, a chlorinator or chemical feeder may be the answer—that, or a new well. 





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