## 5 Assessment of Leak Detection Methods
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Category** & **Methods** & \
\begin{tabular}{c} **Leak** \\ **Sensitivity** \\ \end{tabular} & **Accuracy** & **Leak Location** &
\begin{tabular}{c} **Real-Time** \\ **Monitoring** \\ \end{tabular} & **False Alarms** & **Cost** \\ \hline \multirow{4}{*}{Non-Acoustic} & Visual survey & Low & Moderate & Yes & No & Low & Low \\  & Gas injection & High & High & Yes & No & Low & High \\  & Thermography & Medium & Medium & Yes & No & Medium & High \\  & Ground-penetrating radar & Medium & Medium & Yes & No & Medium & High \\  & Negative-pressure waves & High & High & Yes & No & High & Medium \\ \hline \multirow{4}{*}{Acoustic} & Manual listening sticks & Medium & Medium & Yes & No & Medium & Low \\  & Leak noise correlation & Medium & Medium & Yes & Yes & Medium & High \\  & Leak noise loggers & Medium & Medium & Yes & Yes & Medium & High \\ \hline \multirow{4}{*}{Inline} & Sahara & High & High & Yes & No & Low & High \\  & SmartBall & High & High & Yes & No & Low & High \\  & Fiber optic & High & High & Yes & Yes & Low & High \\ \hline \multirow{4}{*}{Software-based} & Flow variation method & Low & Low & No & Yes & Low & Low \\  & Pressure point analysis & Medium & Medium & No & Yes & Medium & Medium \\  & Water balance method & Low & Low & No & Yes & Low & Low \\  & Numerical methods & Medium & Medium & No & Yes & Medium & Medium \\  & Support vector machines & High & High & Yes & Yes & Low & Medium \\  & Deep learning & High & High & Yes & Yes & Low & High \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparative analysis of various techniques for detecting water leaks. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & **Methods** & **Limitations** & **Improvements for Future Research** \\ \hline \multirow{4}{*}{Non-Acoustic} & Visual survey & Detection of visible surface & Develop complementary technologies for a more comprehensive leak assessment \\  & & water leaks only [91]. & \\  & & & beyond detecting surface water leaks only. \\ \cline{2-3}  & Gas injection & Accuracy affected by environmental factors, such as wind, temperature, and gas & Refining the gas injection process, including the selection of suitable tracer gases. \\ \cline{2-3}  & & & dispersion characteristics [92]. & \\ \cline{2-3}  & Thermography & Insufficient temperature differential [93]. & Improve its sensitivity to detect minor \\  & & & temperature fluctuations. \\ \cline{2-3}  & Ground-penetrating radar & Difficulty in differentiation between water & Adapt to diverse soil types and differentiate \\  & & pipes and other buried objects [94]. & various subterranean characteristics. \\ \cline{2-3}  & Negative-pressure waves & Accuracy highly affected by pipe material, diameter, and network complexity [95]. & Integrate data analysis techniques to address \\ \hline \multirow{4}{*}{Acoustic} & Manual listening sticks & Less efficient in large systems or noisy urban environments [96]. & Develop noise-filtering technologies and automated detection mechanisms to reduce human error. \\ \cline{2-3}  & Leak noise correlation & Sensitive to pipeline materials, diameters, and network complexity [97]. & Integrate calibration methods to consider diverse pipeline configurations. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Limitations and required improvements of various techniques for detecting water leaks.