In an earlier blog, I mentioned that nonrevenue water is the difference between the volume of water supplied to a system and the volume that is billed to its customers. This can also serve as a form of waste, as well as cost a municipality tens of thousands of dollars. According to the U.S. Environmental Protection Agency (EPA), about 17 percent of treated water is lost due to leaky pipes. Here’s some food for thought. New York City loses anywhere from 33 – 37 million gallons per day (MGD), with some estimates ranging up to 300 MGD of the 1.2 billion gallons a day distributed to its citizens.
The first phase of leak control is detecting the location of the system’s leaks. There are various methods used to perform the detection, in hours rather than minutes. Some municipalities want to locate and repair leaks, but feel that lack the time, techniques or manpower to do so. The following information will be a guide in finding leaks and starting a leak detection program, which will cut costs.
First, establish a way to manage the system’s leaks by either creating a leak detection management plan or having a full-time leak detection person or crew to search and repair system leaks. The management plan would specify time periods where personnel are designated to search for leaks.
There are four basic leak detection management activities–– pressure management, speed and quality of repairs, active leakage control and pipe materials’ management. All of these programs position the system to recover real income losses through system optimization. Managing pressure in the system is vital for several reasons. The two most important are meeting regulations and delivering desirable pressure to the customers. In addition, avoid over-pressurizing pipes. Prepare for, inspect and prevent situations where thrust blocking can occur.
The timeliness of leak detection and repair can be critical to the success of the leak detection management plan. As noted in the chart at the left, very small leaks can generate large volumes of water loss over short periods of time. These numbers show that finding and repairing leaks, not only in a timely manner, but with proper techniques and quality material can be the difference in a monthly, or even a yearly, budget. How much would 400,000 gallons of lost water revenue cost your municipality or system?
As you select pipe materials, whether it is for a new installation or a repair, it is critical that you are using the right materials for the job. Consider not only the material cost, but what is coming through the pipes in that area of town. Can the fittings withstand the contents? How often will routine and major maintenance have to be performed? Are you using the proper bedding and making sure a competent person checks behind the contractor or installer to ensure that the installations were done properly?
Replacement and repair costs should also be considered, since they determine future practices that can be performed, as well as budget control. Savings like these can also help fund manpower and other portions of the leak detection management plan and continue to serve the system. When these principles and techniques are followed, controlling a system’s water loss is easier. Minimizing a system’s water loss protects a precious resource and saves money.