You did not mention that the majority of Honolulu's water pipes are in ancient coral reef Karst. When the pipes were all layed in the coral Karst,  trenches were dug, metal pipe put in and then back filled with crushed coral. These coral trenches then become, with rising salt water and ground water ahead of it, conduits for water to move in and out. Basically along with natural underground springs and streams, the pipe trenches become subsurface waterways. The crushed coral gets washed away and the old pipes corrode and break because the fill is gone. Its a massive problem only getting much worse.
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Instead of dealing with it like in Kakaako and other shoreline communities, the City has largely ignored it, spending all the money, and future property tax money, on insanely expensive rail construction. All of downtown Honolulu and Waikiki are in coral reef Karst, and in fact nearly all areas up to at least 40 feet above sea level which is where the ancient coral reef used to extend.