This paper presents results of an assessment of several solar water units to determine causes of their malfunctioning. A survey of solar water heater (SWH) installations in the Gaborone area, Botswana was carried out to obtain performance characteristics of SWH in the local market. Extensive inspections were performed on both in-service and non-functioning units, problems were diagnosed and pragmatic solutions were proffered. The paper presents some of the discoveries made during the investigation, namely, several units did not last up to the payback period of say 10 to 15 years. The results obtained could provide guidance in selecting operating criteria and suitable system design for solar water heating applications.