Swimming at Lake Darling is not recommended at this time due to recent E. Coli samples from Lake Darling revealing another spike in bacteria levels. The latest single sample of E. Coli collected on July 21 came back with 340 colony forming units per 100 milliliters of water. This caution for swimming at the lake was put out by the Iowa Department of Natural Resources and will be in effect until E. Coli levels for a single sample read 235 colony forming units or lower. Iowa DNR Lake and Beach Monitoring Coordinator Daniel Kendall says swimming in lakes with higher E. Coli levels can be harmful if you ingest the lake water. Issues that could arise include intestinal problems, diarrhea, chills, and stomach cramps. He also says parasites can lurk in these lakes and cause intestinal cramps and vomiting if lake water is ingested.