Contemporary understanding of agricultural development options for smallholder farmers in Sub-Saharan Africa (SSA) follows several narratives. One such narrative is that the global population will reach 9.5 billion by 2050 and global food production needs to double to ensure adequate global food supply. Furthermore, SSA can support the projected increase in production through agricultural intensification. The latter will require significant investments to increase land under irrigation. Major constraints to agricultural intensification are lack of land ownership and land fragmentation. Much agricultural land in SSA consists of small parcels of 0.5-2 acres that are under some type of customary ownership. Policy initiatives, e.g. in Rwanda and Ethiopia, aim to re-allocate land in order to consolidate it for agricultural intensification with improved technology adoption. These schemes are usually driven by funding from external NGOs or government agencies which makes their long-term sustainability questionable. We applied the Common Pool Resources (CPR) management principles to evaluate the sustainability of a 200-acre irrigated farm that is comprised of 400 household plots of 0.5 acres each. The scheme was developed by and continues to receive support from, an international NGO in two villages in northern Tanzania. The region has low rainfall (~300 mm per year) and there have been several failed community irrigation schemes in the region. This project employs novel operational rules that are supported by the communities. We collected data over two years, including household questionnaires, key informant interviews, and focus group discussions. Our findings suggest that unclear group boundaries and increased pest and disease prevalence are undermining the farmer’s sustainability. The high maintenance cost of irrigation equipment also undermines financial sustainability. This study gives important insights into how collective irrigation schemes can be designed and managed adaptively for community benefit in SSA.