The Multiplier Effect.
Water infrastructure is something that is taken for granted in MEDC (more economically developed countries) but it is severely lacking in LEDCs (less economically developed countries). Large investments into water infrastructure leads to several multiplier effects; the most obvious is the increase in positive health trends. Clean water eradicates a large source of disease in the developing world and subsequently enables more of the population to contribute economically to their communities.
A more nuanced benefit is the increase in jobs that improving or creating water infrastructure brings. Construction companies build the infrastructure and will continue to repair and replace these systems as they age, specialist equipment is manufactured to aid in the development of infrastructure and the procurement of raw materials is needed for this manufacturing process. These concepts even filter down to the production of what we would consider necessities such as showers and toilets. Their production, installation and maintenance all contribute towards the multiplier effect and improving the economies they are implemented in.
Lastly the greater the gap is between the amount of water infrastructure needed and the current amount being supplied the greater the multiplier effect is. This is why investment into infrastructure should be a priority of LEDC nations where water provision is at its lowest. The closer we get to achieving total water provision for everyone, the closer we get to being prosperous together.