Before drilling starts, it is good to analyse where the water might be. There are lots of clues to look for in WellSpringAfrica.org's [http://www.wellspringafrica.org/WebManual/chapter4.htm Selecting a Site.]
{{procontable | proborder="1" cellpadding="5" cellspacing="0" align="center"|-! width="50%" style="background:#efefef;" | Advantages! style="background:#ffdead;" | Disadvantages|-| valign="top" | - Unlike any other drilling method, percussion can remove boulders and break harder formations, effectively and quickly through most types of earth. <br>
- Percussion drilling can in principle deal with most ground conditions.<br>
- Can drill hundreds of feet (one well hand-drilled in China in 1923 was over 4000 feet deep). <br>
- Can drill further into the water table than dug wells, even drilling past one water table to reach another. <br> | convalign= "top" | - The equipment can be very heavy and relatively expensive. <br>
- Especially in harder rock the method is slow (weeks, rather than days). <br>
- When temporary casing has to be used, the time taken driving and removing it can significantly increase drilling time.<br>
- Equipment costs are high and the method is slow (resulting in high cost / drilled meter).<br>|}}
==Construction, operations and maintenance==