The reference, given below, includes several tests on oil including the saponification value & the water content, in detail.

In our laboratories, we apply a simple procedure to find out the % water in an oil sample. Each group, of my students, weighs 5.0 g. of oil in a flat Pyrex glass dish & places it in an oven set previously at 103 oC . It is left for half an hour & then taken out. After cooling, weight is measured. Assuming that the weight of oil has become 4.9 g. then the % of water is = (0.1/5.0) X 100 = 2 %.