The　gravity-driven　membrane　(GDM)　systems　offer　a　promising　solution　for　decentralized　drinking　water　supply　due　to　its　low　maintenance　and　energy　consumption.　However,　research　on　the　practical　application　of　GDM　under　variable　hydrostatic　pressure　(variable　load)　and　intermittent　operation　conditions,　particularly　in　response　to　high-turbidity　water,　remains　limited.　This　study　investigates　the　long-term　performance　and　characteristics　of　the　biofouling　layer　of　GDM　under　ultra-low　variable　hydrostatic　pressure　(20–60　mbar)　and　intermittent　operation　(8–12　h)　conditions　in　practical　decentralized　water　supply.　The　results　indicate　that　the　membrane　flux　(1.9–6.0　L∙m−2∙h−1,　LMH)　remained　relatively　stable　despite　variations　in　gravity-driven　pressure　(ΔP).　Long-term　operation　of　GDM　can　stably　remove　turbidity　and　potential　pathogens　from　raw　water.　The　total　protein/polysaccharide　ratios　of　extracellular　polymeric　substances　(EPS)　in　the　biofouling　layer　were　below　0.50,　reducing　contaminant　adhesion　on　the　membrane　surface.　The　0.2–0.4　μm　transparent　exopolymer　particles　(TEP)　fraction　might　be　crucial　for　biofouling　layer　formation.　The　key　species,　belong　to　Proteobacteria　and　Patescibacteria,　significantly　alleviated　membrane　fouling　by　degrading　polysaccharide　and　proteins　in　biofouling　layer.　Comammox　Nitrospira　were　significantly　enriched,　contributing　to　efficient　nitrification.　GDM　with　variable　load　maintained　a　stable　flux　of　2.2–5.2　LMH　under　high-turbidity　water　conditions　(300–1200　NTU),　and　simple　forward　flushing　combined　with　sludge　discharge　can　quickly　restore　ΔP.　Overall,　the　variable　load　GDM　system　effectively　manages　membrane　fouling　and　maintains　stable　filtration　performance　through　the　combined　effects　of　variable　load　and　intermittent　operation,　ensuring　long-term　and　low-maintenance　operation　for　decentralized　water　supply.　©　2024　Elsevier　B.V.