We have completed a set of CAD models and drawings for our “Pre-Series 0” prototype. This improves on the gamma uDAHR, currently in operation in Kenya and Bangladesh, in a number of ways. The PS0 offers larger diameter pipework connections with implied greater hydraulic efficiencies (>80%, c.f. 70-75% previously) without increasing the pump diameter. It self-starts with all drive pumps (c.f. only drive pumps with a significant “unsteady” component to their flow), and auto-recovers from dry-running without the need for re-priming. Accelerated testing also indicates a much longer service interval than the gamma-uDAHR is possible. However, this is hard to prove as no gamma uDAHRs have yet required service!