Majority of fixed offshore platforms in Brunei employ open drain caissons as a practical approach for collecting drains. It consists of a pipe submerged into the sea with an open bottom without any internals. Density and insolubility of the oil enables it to separate over time and settle atop of sea water within the open caisson and it is eventually removed via a pump through an oil level measurement and control system. Due to tidal variations in sea levels offshore, oil level monitoring and control of the open drain caissons alone is difficult. Majority of level measurement techniques employed no longer operate and/or do not give an accurate and reliable oil level indication. This leads to manual operation of the oil pump and in most cases, seawater is also pumped out along with the oil resulting in potential microbiologically induced corrosion on downstream systems. Inaction on this matter can potentially lead to, at worst case, loss of oil containment as the open drain caisson capacity is limited. This paper aims to study and provide recommendation to improve level measurement and control of open drain caissons on fixed offshore platforms whilst minimizing modification or re-design of the existing open drain caissons.