The Lot 46 Valley Gardens TCE site sits in Des Moines, Iowa, and was added to the Superfund National Priorities List in 2024. Trichloroethylene (TCE), a volatile organic compound widely used in industrial processes, has contaminated groundwater beneath the site. A second source of contamination may also be present. The Iowa Department of Natural Resources began investigating the groundwater plume in 2004, and the EPA took the lead in 2020. The site has one active operable unit focused on groundwater contamination.
The main contaminants are TCE and cis-1,2-dichloroethylene (cis-1,2-DCE), a breakdown product of TCE. Both have been detected in water samples from the Des Moines Water Works Fleur Drive Treatment Plant intake gallery near the Raccoon River, but at levels below the EPA's Maximum Contaminant Levels for drinking water. Trace amounts of cis-1,2-DCE have also appeared in finished drinking water from the plant, again below those standards. Des Moines Water Works regularly samples its supply to check quality. The EPA is also investigating whether TCE vapors are moving from the groundwater into buildings above, though no significant vapor exposure risk has been identified so far. Recreational use of Water Works Park and normal business activity within the site boundary can continue as usual.
The groundwater plume is not yet stabilized, and no cleanup remedy has been selected. The next major step is a combined Remedial Investigation and Feasibility Study, estimated to start between September and November 2026. That study will map the full extent of contamination, assess risks to human health and the environment, and identify cleanup options.
No public meetings or comment periods are currently scheduled. Residents can join the site mailing list to receive updates and notices of future participation opportunities. Two free support programs are available to community members. The Technical Assistance Services for Communities program connects residents with scientists and engineers who can explain environmental information. The Technical Assistance Grant program offers up to $50,000 in initial funding to community groups who want to hire their own technical advisor to review reports and EPA proposals. Public records related to the site are available at the Des Moines Public Library Central Branch at 1000 Grand Avenue.
