Objective: To understand the hydration status and related factors of rural boarding primary school students, so as to provide a scientific basis for drinking water health intervention for primary school students. Methods: In November 2023, a convenience sampling approach was employed to conduct a hydration status survey among 144 boarding students in grades 5 and 6 of a rural primary school in Guangxi. The Duplicate meal method and weighing method were utilized to measure the food derived water intake over three consecutive days. Urine osmolarity of students was measured on site for three days, and a simple physical examination was also carried out. A self administered questionnaire was used to investigate students drinking water literacy, daily water intake, and physical activity levels. Meanwhile, a drinking water literacy survey was conducted among 21 substitute teachers and 144 parents of the boarding students in grades 5 and 6. Logistic regression was used to identify factors associated with students hydration status. Results: The median daily total water intake of students was 2 043.55 mL, and 54.86% of the students did not reach the recommended Adequate Intake (AI). The median food derived water intake was 1 149.24 mL, accounting for 53.94% of the total water intake. Univariate analysis revealed that the daily drinking frequency, daily water intake, and food derived water intake of students were related factors of hydration status ( β =-1.60, -1.01, -0.00, all P <0.05). Multivariate Logistic regression analysis showed that primary school students with a daily drinking frequency of ≥7 times were more likely to maintain an adequate hydration status ( OR =0.28, 95% CI =0.09-0.93, P ＜0.05). Conclusions The water intake from food is the main source of water in the body for boarding primary school students in a certain rural school in Guangxi. Primary school students should increase their water intake frequency appropriately to maintain an adequate hydration status.