The accumulation of organic pollutants in Indonesian waters is challenging for water treatment. Because high pollutant levels increase the burden on the water technology used. Membrane technology can be used to optimize the filtration of organic pollutants. However, this technique is still limited by the fouling phenomenon on the membrane surface. The aim of this study was to investigate the effect of humidity on the structure formation and antifouling properties of the fabricated polyethersulfone (PES)-polyethylene glycol hexadecyl ether (PEG-HE) membranes. The PES membrane was modified by adding the additive PEG-HE and printed using the Vapor and Non-solvent Induced Phase Separation (VNIPS) technique with air humidity of 70% and 90%. Changes in membrane properties and performance were analyzed before and after modification. Overall, the results show that adding 3% PEG-HE additive and using the VNIPS technique have a good impact on the membrane, namely, increasing the hydrophilicity, as well as the number and size of pores. The PES membrane modified with PEGHE additives and 90% air humidity exhibited the highest stability in various aspects of analysis, such as a water contact angle of 55.11°, a pure water flux of 69.86 L/m2.h, a Flux Recovery Ratio (FRR) of 91.91%, and humus acid rejection of 86.84%. In conclusion, the present research provides valuable insights into developing PES membranes with antifouling properties for filtering organic pollutants.