Leak detection surveys will be conducted to locate and quantify specific points of leakage across the water
distribution system. The quantity of leakage will be estimated by the consultant and used to identify necessary
remedial actions to reduce system leakage.
The first step will always be leak detection, for which a field crew will establish “listening points” via physical contact
with valves, hydrants, pipes, B-boxes, meter settings etc., to listen for leak noises escaping from fire hydrants,
accessible main-line valves, and select service connections throughout the distribution system. Listening points have
been prioritized with the following order: direct contact with the pipe, main-line valves, hydrant valves, hydrants, and
service valves or meter settings. The Project Team will use state-of-the-art Electronic Leak Correlators (ELCs) to
determine if a leak is present and then to pinpoint the leak.
Pipe material will define the specific listening distances. These distances shall be no more than 500, 300, and 150
feet for metallic, non-metallic AC/concrete, and non-metallic PVC/HDPE pipes, respectively.
All areas where leak noise is detected and/or suspected will be maintained in a “suspected leaks” log. This log will be
referred to as the Project Team verifies the area of the suspected leak to confirm its actual location. This log will be
included in regular reports to DWSD regardless of whether or not an actual leak is found. The source of the noise will
also be explained in the log. After logging an initial suspected leak noise, the Project team will do a second
verification to confirm the leak noise detected. This procedure will take place at least four (4) hours after the first
listening.
The field crew will line-locate water mains and service lines within the study area so that correct
pipe distances can be entered into the ELC and make DWSD aware of the location of all water mains before
excavation. Non-metallic piping locations will be determined as specifically as possible based on the location of the
line of the metallic services, DWSD’s knowledge of the surrounding area, and/or other information regarding the
main’s location. Each field team will indicate leak locations on the surface using environmentally formulated,
precautionary blue paint.
The Project Team will document all leak locations with a diagram indicating the location of the leak and input this
information into Cityworks. Other information related to detected leaks, such as filters used for the correlation, line
locations, distances between sensors, etc., will also be input. The quantity of leakage will be estimated by a
consultant and used to identify necessary remedial actions to reduce system leakage. The locations of leaks
requiring immediate attention (because they stand to cause a threat to life, injury, or traffic) will be prioritized within
the repair process. The data will be collected into a Cityworks leak detection inspection survey. This system will
automatically create work orders on assets that leaks are detected on with all required information necessary to
prioritize, locate, and address repairs.
