Regenerator bottoms from hydrogen fluoride (HF) alkylation are often 2-phase systems. The lower phase is relatively rich in HF, containing about 30-40%; and the upper phase is essentially hydrocarbon containing small concentrations (about 0-5%) of HF. The water content of the HF-rich lower phase is usually less than 10%, and that of the upper phase is usually less than 5%. This method is satisfactory for the determination of water in both types of samples. The unsaturates present in the oil do not interfere in the titration for water.