Samples of water isotopically enriched in 17O, 18O, and 2H along with natural water were bombarded by neutrons from the intense deuterium-tritium source provided by the Fusion Neutron Source facility. After irradiation, the accumulated concentrations of 3H and 14C activities were determined by the liquid scintillation method. Special attention was paid to 14C losses in the gas phase during irradiation and preparation of scintillation counting samples. Cross sections for the 17O(n,)14C, 18O(n,n')14C, 17O(n,t)15N, and 18O(n,t)16N reactions at 14.7 MeV have been measured for the first time. The following values have been obtained for these reactions: 18.0 ± 3.3, 35.4 ± 6.5, 0.82 ± 0.15, and 26.8 ± 4.9 mb, respectively, relative to the 93Nb(n,2n)92mNb standard reaction cross section of 460 mb. A study of the systematics of (n,t) reactions at 14.7 MeV on light nuclei (atomic number Z < 10) has been carried out. The experimental cross-section values are also compared with data in the comprehensive activation libraries.