The daily per capita costs of all NSS scenarios were most sensitive to labor wages (OP operator wage for the Biogenic Refinery and CRT labor wage for the NEWgenerator and Reclaimer) and the price level ratio. The Biogenic Refinery relies on a daily operator to manage and oversee the system, and uncertainty in wages leads to higher uncertainty in the overall cost of the system. The NEWgenerator and Reclaimer do not require an on-site operator but do require periodic maintenance for treatment operations. Labor wages were estimated using the "water supply, sewerage, and waste management and remediation activities" economic activity average monthly wage for a country . Although this economic activity best represents the activities necessary to operate and maintain the NSS systems, 50% uncertainty was added to the reported wages to account for the limited information regarding wages. The price level ratio was the key contextual parameter used to convert generalized material costs to country-specific costs. The magnitude of the ratio directly alters the expected capital and consumables costs of the system, resulting in high correlation with the calculated daily per capita cost of each NSS system.