Declining water levels caused by withdrawals of water from well in Akaki , thernsouthern part of Addis Ababa have raised concerns with respect to the ability ofrnthe aquifer system to sustain production . As the aquifer of akaki in particular isrnheavily used in this area , understanding the hydraulic parameters of the area isrnessential for efficient sustainable management of the groundwater resource . A singlernwell test was conducted to estimate the hydraulic parameters of the aquifer. An overviewrnof the hydraulic parameters estimated for the 12 wells in the study clearly show strongrnevidence of inappropriate estimation. Thus this study was conducted to identify thernpossible miss-interpretation of the observed time-drawdown , step-drawdown , timeresidualrndrawdown based parameter estimation . After data quality checking , appropriaterndata correction for partial penetration and unconfinedness (if exists) were conducted.rnThen the standard methods like Theis curve fitting, Cooper-Jacob methods for timedrawdownrndata & Theis recovery method for time-residual drawdown data were usedrnfor parameter estimation. Beside Aquifer test v3.5 software was also used to verify thernresults of the original study. Evaluation and analysis result showed that out of the 12rnwell analyzed , 11 transmissivity values used in the well yield estimate werernoverestimated (on an average of twenty times ) and one underestimated (fivefold) ,rnsuch highly over estimated transmissivity value misleads the designers & operators inrnfixing the well yield . Therefore, in this evaluation it is recommended to conductrnmultiple well test to determine the actual hydraulic parameters of the aquifer inrnorder to obtain the safe yield of the wells which is intended to prolong thernproductivity of the aquifer and to delay excessive loss of saturated thickness .