For this job, we returned to evaluate a reported sulfur smell in the home’s water following a previous visit in which the water softener and whole-house filtration system were serviced. During this visit, a sulfur odor was present. While on site, the customer replaced the carbon filter, and the odor noticeably subsided afterward. Based on our findings, we recommended completing an Endym water test or a standard laboratory water analysis to accurately identify the cause of the odor and determine whether an air cycle treatment unit would be appropriate. We explained that proper system sizing would depend on the test results, and we will provide detailed recommendations and estimates once the test results are received from the customer.