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-κ3　N: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.　©　2015　International　Union　of　Crystallography.