However, they do not effectively remove many microorganisms. In addition, RO systems are subject to membrane fouling. This occurs when unfavorable water conditions create a coating on the membrane, reducing the treated water quality and quantity over time. Fouling is the most significant factor affecting the performance of membrane processing systems, causing a reduction in product water quality and flow. Even the best RO system becomes less effective over time.
Premature failure is common, often due to improper installation or defective components.
Most systems require professional monitoring, water testing and maintenance. Regular replacement of the membrane and filters is necessary and costly. These expensive membranes need to be replaced about every 12 months to 24 months depending on deterioration, water condition and usage. Most RO systems use plastic materials to house the membrane and to store treated water. These plastic components often warp, crack and leak, leading to additional replacement expenses.