The title compound, {[Ag(C6H7AsNO3)(C18H15P)]·H2O}n, has been synthesized from the reaction of 4‐aminophenylarsonic acid with silver nitrate, in aqueous ammonia, with the addition of triphenylphosphane (PPh3). The AgI centre is four‐coordinated by one amino N atom, one PPh3 P atom and two arsonate O atoms, forming a severely distorted [AgNPO2] tetrahedron. Two AgI‐centred tetrahedra are held together to produce a dinuclear [Ag2O2N2P2] unit by sharing an O–O edge. 4‐Aminophenylarsonate (Hapa−) adopts a μ3‐κ3N:O:O‐tridentate coordination mode connecting two dinuclear units, resulting in a neutral [Ag(Hapa)(PPh3)]n layer lying parallel to the (10) plane. The PPh3 ligands are suspended on both sides of the [Ag(Hapa)(PPh3)]n layer, displaying up and down orientations. There is an R22(8) hydrogen‐bonded dimer involving two arsonate groups from two Hapa− ligands related by a centre of inversion. Additionally, there are hydrogen‐bonding interactions involving the solvent water molecules and the arsonate and amine groups of the Hapa− ligands, and weak π–π stacking interactions within the [Ag(Hapa)(PPh3)]n layer. These two‐dimensional layers are further assembled by weak van der Waals interactions to form the final architecture.