This study employs stochastic frontier analysis to estimate the production and profit efficiency implications of water quantity constraints and water cost escalation among 220 citrus smallholder production units surveyed across five district municipalities in Limpopo Province. Maximum likelihood estimation results for the normalised profit frontier model reveal that water quantity is the dominant negative predictor of production outcomes (coefficient beta = 0.671, p < 0.001), while water cost is the second largest positive predictor in the profit function (beta = 0.365, p < 0.001) after fertiliser cost (beta = 0.380, p < 0.001), together explaining over 40% of the explained variance in normalised profit. Mean profit efficiency is estimated at 0.74, with water access insecurity identified as the primary driver of profit efficiency shortfalls in the sub group of farmers scoring below the 0.60 viability threshold. Analysis of irrigation infrastructure conditions reveals that 62.3% of sampled production units operate below optimal irrigation system efficiency, and that inadequate water access was rated the most severe adaptation barrier in the dataset, with a mean Likert severity score of 4.2 out of 5.0. Ordinal logistic regression confirms that water access insecurity is the second strongest negative predictor of climate adaptation intensity (OR = 0.51, p < 0.001). These results carry direct implications for the South African National Water and Sanitation Master Plan, agricultural water pricing reform, and the integration of irrigation infrastructure investment into the country’s climate adaptation strategy for commercial horticulture.