In 2016, EPAL recognized a deviation in the non-revenue water (NRW) trend since implementation of the DMA program. The issue was promptly identified in two supply zones, encompassing 150 kilometers of water transmission mains, predominately composed of large diameter reinforced concrete pipe built in 1965.

Over the last few years, the operation and maintenance of the large valves had declined due to focus being placed on other critical priorities. Without a consistent exercise routine for critical valves, the utility found that many of these valves were inoperable and, as a result, began to seek funding for valve replacements.

New standards of best practice for force main management involve a variety of methods and technologies to provide data and information with which to make decisions. Utilities can now often perform a detailed condition assessment while the force main remains in service.

As part of a pre-emptive program to address non-revenue water loss and understand the condition of their pipes, Gothenburg wanted to conduct a condition assessment and leak detection survey on a series of large diameter transmission mains. The three pipelines were built in the 1960s and made of cement and steel, ranging in size from 1000 mm to 1200 mm.