Wax　deposition　in　crude　oil　pipelines　critically　undermines　flow　efficiency　and　increases　operational　costs,　yet　the　aging　behavior　of　wax　deposits　in　polyethylene　pipelines　under　water-containing　conditions　remains　underexplored.　This　study　presents　systematic　investigation　into　the　water-containing　aging　dynamics　of　wax　deposits　in　polyethylene　pipelines,　addressing　a　gap　in　multiphase　flow　deposition　research.　A　flow　loop　with　interchangeable　polyethylene　and　steel　test　sections　was　employed　to　conduct　wax　deposition　experiments　under　water　contents　(0–50　vol%)　and　temperature　conditions　(bulk　25–29　°C,　wall　19–23　°C).　Differential　scanning　calorimetry　was　used　to　quantify　wax　content,　while　heat　transfer　and　wax　precipitation　analysis　provided　insights.　Innovatively,　polyethylene　pipes　demonstrated　16.3–68.3%　lower　aging　rates　than　steel　pipes　under　identical　conditions,　directly　attributed　to　their　15.6–32.2%　lower　radial　concentration　gradients.　This　reduction　is　linked　to　polyethylene’s　inherently　lower　thermal　conductivity,　establishing　a　novel　material-driven　correlation　in　wax　deposition　dynamics.　Notably,　when　the　water　content　reaches　50　vol%,　this　causes　phase　inversion　of　the　emulsion,　resulting　in　negative　aging　rates　of　the　deposition　layer.　These　findings　redefine　design　parameters　for　high-water-cut　polyethylene　pipelines,　enabling　predictive　maintenance　to　minimize　pigging　frequency.　©　2025　Taylor　&　Francis　Group,　LLC.