The pump is fitted with a non-return valve on its outlet to prevent water from flowing back into the borehole when pump is switched off; nevertheless, it is recommended that an additional non- return valve be installed on the surface delivery pipe as default especially on long pipelines.

To ensure borehole sustainability and avert pump failure due to over pumping, the pumped output should not exceed 70% of the tested borehole yield, in other words if the borehole yield is 3m3/hr, the maximum abstraction will be 2.1m3/hr

For a solar scheme the size of the storage tank should be determined by the daily demand and should be large enough to store as much water as possible during sun hours. A tank that is at least 1.5 – 3 times the daily demand is recommended. Areas that have significant seasonal variations in irradiation (due to weather) the tank would be greater than in areas where there is less variation.