This article discusses and compares the effectiveness of the compound and dual technique-based inline strategy used to upgrade existing steel pipe-based water supply systems. Basically, these techniques are based on splitting the single inline short section, used in the conventional technique, into a couple of two sub-short sections made of two distinct plastic material types: high- and low-density polyethylene (HDPE) and (LDPE). The 1D unconventional water hammer solver based on the method of characteristics was used for numerical computations. Results evidenced that the specific setup of the compound technique based on (HDPE-LDPE) sub-short sections (where the former sub-short section is attached to the hydraulic parts, while the latter is attached to the main steel pipe) is the most prominent configuration providing an acceptable trade-off between attenuation of pressure head surge, and limitation of excessive wave oscillation period spreading. Furthermore, this compound technique setup allowed more important pressure head peak (or crest) attenuation as compared with the dual technique based on (LDPE-LDPE) sub-short sections; while inducing about similar values of wave oscillation period spreading.