Nonrevenue water is the difference between the volume of water supplied to a system and the volume that is billed to its customers. There are many factors that can contribute to this volume difference. This includes, but is not limited to, unbilled authorized consumption, apparent loss and real loss. Nonrevenue water loss is now estimated to be, worldwide, a loss of over $18 billion annually. A 1/8-inch hole in a main or pipe can cause a loss of one million gallons per year. The first approach to attacking nonrevenue losses is to understand the causes and effects of your municipality’s specific contributors to the losses. A water audit should be conducted and used to strategize water-loss reduction.
Technology is getting better at contributing to leak detection. There are now Windows-based leak detection systems that use leak-noise correlations to pinpoint seepages in all types of water and fluid pipes, including plastic pipes. By using personal computers, the reliance on the hardware component of leak-noise correlators is eliminated. By using the faster microprocessors of personal computers, the enhancement of correlated function can be dramatically improved in identifying narrow-band leak noise. It also increases the chances of locating small leaks, or situations that have high background noise. So as you begin to fight the nonrevenue water monster, make sure you use the weapons of auditing, new technology, intervention, evaluation and common sense.