Aldosterone increases tubular sodium absorption largely by increasing epithelial Na⁺ channel (ENaC) α transcription in collecting duct principal cells. How aldosterone reprograms basal ^αENaC transcription to high-level activity in the collecting duct is incompletely understood. Promoter methylation, a covalent, but reversible epigenetic process, has been implicated in the control of gene expression in health and disease. We investigated the role of promoter methylation/demethyation in epigenetic control of basal and aldosterone-stimulated ^αENaC transcription in mIMCD3 collecting duct cells. Bisulfite treatment and sequencing analysis after treatment of the cells with the DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) identified clusters of methylated cytosines (5mC) in a CpG island near the transcription start site of the ^αENaC promoter. 5-Aza-CdR treatment or siRNA-mediated knockdown of DNMT3b or methyl-CpG binding domain protein (MBD)-4 de-repressed basal ^αENaCtranscription, indicating that promoter methylation suppresses basal ^αENaC transcription. Aldosterone triggered a time-dependent decrease in 5mC and DNMT3b, and a concurrent enrichment in 5-hydroxymethylcytosine (5hmC) and ten-eleven translocation (Tet) 2 at the ^αENaC promoter, consistent with active demethylation. 5-Aza-CdR mimicked aldosterone by enhancing Sp1 binding to the ^αENaC promoter. We conclude that DNMT3b- and MBD4-dependent methylation of the ^αENaC promoter limits basal ^αENaC transcription, in part by limiting Sp1 binding and ^trans-activation. Aldosterone stimulates dispersal of DNMT3b and recruitment of Tet2 to demethylate the ^αENaC promoter to induce ^αENaC transcription. These results disclose a novel epigenetic mechanism for control of basal and aldosterone-induced ^αENaC transcription that adds to previously described epigenetic controls exerted by histone modifications.