From my experience, ABS pipes much much versatile and if installed correctly will be in service for many2 years compared to pvc pipe or any other types. ABS pipes expecially its fittings is crucial that one get the same brand. So the fit is exact. Cutting of the ABS also have their specific tools, unlike pvc where any hacksaw can be used to cut the pipes. Then comes the ABS cleaner and glue. The glue part can buy any brand no hal, but the clener specific one for ABS, very important. Workers nowadays not like old school workers, they dont have any pride in doing construction, so if can curi tulang, ular, most of he time, the area to be mated are not properly cleaned. So disaster.

For using pumps in the system, best is Groundfos pumps as they are leaders in this field. If using ABS, maximum I would recommend in 2.1 bar. The nominal range for household around 1.2 to 1.6 bar.

For internal house water tank, the best is actually poly tank. Comes in many shapes and sizes. Light, cheap, easy to service and maintain. Only setback is that every few years must perform full internal cleaning to get rid of the blue algae.

It depend on the water quality within your area. Apart from the usual dirt and mud which will accumulate with time, so cleaning is done in one shot. Anyway it is good practise to just do some preventive maintenance which costs roughly RM100 every three years to clean and check the float, lingkages etc