Handpump wells are sanitary because they are closed wells. Handpumps are installed on “tube” wells that are bored deep into the ground. The upper twenty to forty feet of the boring is lined with a steel or plastic retaining sleeve. On top of this a pedestal is mounted and around this pedestal a concrete pad is poured. A water tank with spout is attached to the top of the pedestal. Threaded into the underside of the tank is the first of up to fifteen 10 ft lengths of pipe.
At the bottom of the last pipe is a pump with a plunger attached to the handle at the top of the well through a series of rods and a chain. This construction essentially seals the top of the well from contamination. The water in the boring is clean. Rain water that reaches the water table from above does so only after it percolates through the ground. This process filters the water and provides the necessary time for harmful bacteria to die off. Water pumped to the surface is cool and clean.
Dug wells, on the other hand, are not sanitary because they are open. Although all sorts of debris can and does fall into these wells, the most harmful contamination likely comes from the very containers used to fetch water from these wells. If a bucket that was previously sitting on the ground is attached to a rope and tossed into a well, it can carry into the water contaminants that it picked up from the ground. These contaminants may include fecal bacteria from animal or human sources.
A chlorination program as shown at right is effective at cleaning water from open sources. However, evidence has shown that water from almost all handpumps in our work area is clean and requires no treatment. A few years back a study conducted by The Abdul Jameel Poverty Action Lab in association with Seva Mandir and Vidya Bhavan (both of Udaipur) showed this to be true. Water samples were taken from over 600 dug wells and 200 handpump wells and tested for
both fecal and non-fecal coliform bacteria. The results clearly showed that handpump water is clean. Of the 201 handpump wells tested 3 showed evidence of fecal contamination. When these wells were re-tested the results were negative for fecal contamination. It is suspected that these wells had been opened for repair and were contaminated during this process. Twenty eight percent of the dug wells tested positive for fecal contamination. Although people do drink directly from both types of wells, handpump wells are the clear choice for safe clean drinking water.