The title carbamate monohydrates, C13H12N2O2.H2O and C12H9BrN2O2.H2O, form isomorphous crystals that are isostructural in their primary hydrogenbonding modes. In both carbamates, the primary hydrogen bonding and aggregation involves cyclic amide–water–pyridine moieties as (N—H...O—H...N)2 dimers about inversion centres [as R4 4(14) rings], where the participation of strong hydrogen-bonding donors and acceptors is maximized. The remaining water–carbonyl O—H...O C interaction extends the aggregation into two-dimensional planar sheets that stack parallel to the (100) plane. The Br derivative does not participate in halogen bonding. A weak intramolecular C—H...O hydrogen bond is observed in each compound.