Biotransformation enzyme that catalyzes the hydrolysis of arene and aliphatic epoxides to less reactive and more water soluble dihydrodiols by the trans addition of water. May play a role in the metabolism of endogenous lipids such as epoxide-containing fatty acids. Metabolizes the abundant endocannabinoid 2-arachidonoylglycerol (2-AG) to free arachidonic acid (AA) and glycerol (By similarity). cis-stilbene oxide + H2O = (1R,2R)-hydrobenzoin 1-(4-methoxyphenyl)-N-methyl-N-[(3-methyloxetan-3-yl)methyl]methanamine + H2O = 2-{[(4-methoxybenzyl)(methyl)amino]methyl}-2-methylpropane-1,3-diol 8,9-epoxy-(5Z,11Z,14Z)-eicosatrienoate + H2O = 8,9-dihydroxy-(5Z,11Z,14Z)-eicosatrienoate 11,12-epoxy-(5Z,8Z,14Z)-eicosatrienoate + H2O = 11,12-dihydroxy-(5Z,8Z,14Z)-eicosatrienoate 2-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-glycerol + H2O = (5Z,8Z,11Z,14Z)-eicosatetraenoate + glycerol + H(+) Inhibited by 10-hydroxystearamide and methoxy-arachidonyl fluorophosphate. Belongs to the peptidase S33 family.