In this paper a comparison of the use of Type-1 and Type-2 fuzzy logic in the benchmark problem known as the problem of the water tank is presented. Fuzzy logic allows managing uncertainty, which is very common in linguistic fuzzy systems. It has been shown that Type-2 fuzzy systems manage better the uncertainty in real world problems but, evidence exists also to show that using Type-2 technology is usually computationally more expensive. It is shown in this paper using an experimental basis that an interval Type-2 Fuzzy System presents better results than those obtained with the traditional way of handling fuzzy systems with Type-1 fuzzy logic. Experiments and comparisons are presented to validate the proposed approach.