An improved method of controlled energy delivery utilizing solid, liquid, and gaseous carbon dioxide (CO.sub.2) into a water well and the surrounding aquifer to remove deposited material which may cause loss of capacity in wells and a variety of water quality problems. After proper study and evaluation of problems associated with a well to be treated, adequate injection of the required amount of CO.sub.2 and energy is achieved by real-time monitoring during the injection and manipulating the phase changes in the CO.sub.2 that take place in the well and the aquifer.