Application of Lean Six Sigma for Reducing the Rejection Rate in Water Meter Production

According to the United Nations 2023 World Water Development Report (United Nations 2023), water scarcity represents an imminent crisis affecting between two and three billion people annually, with projections indicating worsening conditions, particularly in urban areas. This scenario underscores the urgent need for effective water management and conservation strategies. In this context, water meters can play a significant role, particularly in controlling consumption, detecting leaks, and raising awareness about excessive water use. Consequently, the water meter manufacturing industry is increasingly vital today.

This study addressed the issue of a high rejection rate in the production of water meters by a company within the metrology equipment industry. The central problem identified concerns one of the company’s most significant products, which had a rejection rate of 53% in 2023—a clear indicator of quality control failures and inefficiencies in the production process. The main issue lay in the costs associated with this high rejection rate, particularly regarding time and resources invested in manufacturing and subsequent rework. The direct losses from rejected products were substantial, compounded by the inability to produce more water meters due to the high rate of rejections, as well as the costs of unnecessary labor and non-conforming water meters. The time and effort expended by the quality team in analyzing and correcting defects were excessive, inflating costs and delaying the production cycle. Additionally, delays in the water meter approval process significantly prolonged the time to market, affecting the production’s responsiveness and agility. Moreover, the surplus inventory of finished products and components resulted in tied-up capital and unnecessary storage space, ultimately limiting the company’s financial health and operational agility. The need for rework due to the high defect rate decreases the availability of labor and machinery, which could otherwise enhance the company’s flexibility to respond more promptly to market demand.

In conclusion, there was a pronounced need within the company to understand the root causes of the high rejection rate for such a financially and operationally significant product. Addressing this problem involves not only reducing the rejection rate of one of the water meters but also strategically adopting the methods used to resolve this specific problem for other types of water meters produced by the company. The goal is to establish a new paradigm of quality for all its products.

Lean Six Sigma,  Rejection Rate,  Water Meter

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