The bailer test: a simple effective pumping test for assessing borehole success

A. M. MacDonald, J. A. Barker, J. Davies

Research output: Contribution to journalArticlepeer-review


A new pumping test method has been designed around the practical requirements of those working in rural water-supply projects in developing countries. The bailer test needs only simple equipment and can be completed in under 1 h. The test involves removing 20-50 bails from a borehole over a 10-min period and then measuring the recovery. The test is analysed using large-diameter-well analysis (which accounts for well storage) and is appropriate for testing low productivity aquifers (transmissivity 0.1-10 m(2) d(-1)), where water levels are shallow (<20 m depth). The bailer test was developed and trialled in a rural water supply project in Nigeria where it was found to predict similar transmissivity to 5-h constant rate tests (r (2)=0.9). Analysis of the test was further simplified to provide guidelines for field staff such as community health workers. The likelihood of a borehole sustaining a handpump for 250 people can be indicated by measuring the maximum drawdown and time for 50 and 75% recovery from a bailer test and comparing to a simple table. This simplified test is now being used in this and other rural water-supply projects, and has been modified to indicate whether a borehole can sustain higher yields for small-scale irrigation.
Original languageEnglish
Pages (from-to)1065-1075
Number of pages11
JournalHydrogeology Journal
Issue number6
Publication statusPublished - Sep 2008


  • Africa
  • Nigeria
  • Hydraulic testing
  • Water supply
  • Groundwater development


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