Acid-catalyzed hydrolysis is not an important mechanism for carbaryl because as a carbamate the central carbon atom is surrounded by two electron-withdrawing atoms (oxygen and nitrogen).  See Figure 3.  The protonation of the carboxyl oxygen would not greatly improve the appeal of the central carbon atom to a nucleophile. Very little research has been conducted on the neutral hydrolysis mechanism for carbamates, although it could be important at pH values found in the environment.

Alkaline hydrolysis is an important mechanism for carbaryl and other carbamates.  For carbaryl, which has hydrogen as the R₁ substituent (see Figure 3), an elimination step is the slow step and determines the rate of hydrolysis.  For other carbamates that have an alkyl group as the R₁ substituent, formation of a tetrahedral intermediate is the rate-determining step.  The alkyl group at R₁ also makes the rate much slower than if hydrogen were present.