In September 2022, the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, collected groundwater-level elevation data and water-quality samples from monitoring wells at the Many Diversified Interests, Inc. Superfund Site in Houston, Texas to evaluate the status of groundwater contamination at this previously remediated site. The dataset includes groundwater-level elevations and field properties measured at 12 monitoring wells along with data from environmental and quality assurance and quality control water-quality samples collected at each well. Water-quality samples were analyzed for arsenic, manganese, molybdenum, benzo(a)pyrene, and petroleum hydrocarbons.