A strain designated PYM3-14T was isolated from the drinking water network of Budapest (Hungary) and was studied by polyphasic taxonomic methods. The straight-rod-shaped cells stained Gram-negative, were aerobic and non-motile. Phylogenetic analysis of the 16S rRNA gene sequence of strain PYM3-14T revealed a clear affiliation with members of the family Xanthomonadaceae within the class Gammaproteobacteria. The 16S rRNA gene sequence of strain PYM3-14T showed the closest sequence similarities to Arenimonas daechungensis CH15-1T (96.2 %), Arenimonas oryziterrae YC6267T (95.2 %) and Lysobacter brunescens UASM DT (94.4 %). The DNA G+C content of strain PYM3-14T, measured by two different methods (52.0 mol% and 55.9 mol%, respectively), was much lower than that of any member of the genus Arenimonas. The predominant fatty acids (>8 %) were iso-C16:0, iso-C15:0, iso-C14:0, iso-C17:1ω9c and C16:1ω7c alcohol. Strain PYM3-14T contained Q-8 as the major ubiquinone and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylmonomethylethanolamine as the major polar lipids. According to phenotypic and genotypic data strain PYM3-14T represents a novel species of the genus Arenimonas, for which the name Arenimonas subflava sp. nov. is proposed. The type strain is PYM3-14T ( = NCAIM B 02508T = DSM 25526T). On the basis of new data obtained in this study, an emended description of the genus Arenimonas is also proposed.