Anyone working on sanitation: service providers, government regulators and development partners. The standard is published as a public good, so using it does not depend on a licence, a project, or on all your data living in one system.
Video: Who can use the Sanitation Asset Standard #mwater on YouTube
A data standard only pays off when the other institutions along the service chain can adopt it too. If it is tied to one organisation's software or one donor's project, it fragments again the moment the project ends. Open availability is what lets a regulator, a utility and an NGO describe the same septic tank the same way, and what makes it safe for a ministry to build national reporting on top of it.