Sending acoustic waves through water pipes to locate leaks is a well-known approach as the country's water and sewage agencies already use this method. The same technology can also be used to successfully estimate appropriate wall thickness of buried water mains. Results from this testing can be used to estimate residual remaining life of the pipe. The method involves sending sound waves through the water main and capturing the speed of sound to determine the thickness of the pipe wall. The method can be applied to a variety of pipe material, and was demonstrated on cast iron and asbestos cement pipes during the field trials.