Pumping tests are used to evaluate aquifers for the purposes of developing water supplies and designing programs for the remediation of contaminated aquifers.   Considerable quantities of water are usually pumped during pumping tests.   The pumped water has to be discharged, and if necessary treated and discharged.   In the case of evaluating aquifer conditions where contaminated groundwater is involved, pumping tests are often not practical because of the generation of contaminated water that has to be either treated or disposed of properly.   Slug tests are often used to evaluate aquifers where contaminated groundwater is involved because little or no groundwater needs to be removed.