Studies reported in the accompanying article of possible causes of poor drainage (despite tile line installations), have also shown that great care must be taken in the construction and location of observation wells used to measure the water table. Open auger holes may be useful to the farmer in determining the water table at one specific time, but are not satisfactory for repeated measurements, especially in unstable soil. Perforated and wrapped plastic wells are desirable for this purpose. For determining the causes of drain failure, however, a wrapped piezometer is recommended because pressures must be determined at specific points. This article discusses the proper construction and placement of observation wells.