WASH infrastructure is the physical hardware that links raw natural water resources to service users; and that takes human excreta and makes it safe before returning it to the environment. Building, maintaining and operating this infrastructure is at the heart of delivering effective WASH services. To do this effectively, the infrastructure itself needs to be appropriate to its context and built and managed to appropriate quality standards. The type of service delivery model is strongly linked to choices about physical infrastructure: a hand-pump will almost never provide the same level of service as a household tap; an open pit latrine is not the same level of service as one that is water sealed. Rapid technological change is radically altering the possibilities of what can be offered to users.
Links to other building blocks: Finance is particularly important to making the right choices for infrastructure: the traditional focus of the sector has tended towards being on initial capital investment at the expense of longer term costs. Monitoring is also essential - to understand how infrastructure is performing and where problems are arising.