The swim beach at Long Branch State Park is open, and the latest state sample is well under the bacteria line that triggers a “swimming not recommended” posting. A different Macon County site, on a Little Chariton tributary, failed every day it was tested in a new statewide report.
The Missouri Department of Natural Resources posted the Aug. 17 sample Friday morning on its public beach table. Long Branch that day: 11.0 and 12.2 E. coli colonies per 100 milliliters, geometric mean 11.6, status Open. The week-of-Aug. 10 row was 5.2, 2.0 and a geomean of 3.2, also open. The legal line is 190. Both recent samples sit far below it.
DNR samples designated state-park beaches every week from Memorial Day weekend through Labor Day weekend. If the geomean exceeds 190, state law (§ 640.080, RSMo) requires a posting that swimming is not recommended. Full reprints of the weekly list show Long Branch open the weeks of July 16, July 23 and Aug. 13. No beaches were on the not-recommended list those weeks.
The numbers are snapshots. Counts move after rain. Anyone headed to the beach this weekend should check the live list at dnr.mo.gov/water/alerts-hazards/beaches before they go.
The park sits two miles west of Macon on U.S. 36, at 28615 Visitor Center Road. The campground is closed for all of 2026 for construction. Missouri State Parks still advertises day use, the beach and the boat ramps. The park office number is 660-773-5229. The U.S. Army Corps of Engineers lake office is 660-385-2108.
A report covered Aug. 18 by KBIA and KCUR put Long Branch in a different dataset. Environment America Research & Policy Center looked at 202 Missouri recreation sites tested in 2024 and 2025. Testing found fecal-indicator bacteria over the EPA freshwater Beach Action Value of 190 cfu/100 mL on at least one day at 171 of them, or 85 percent. Seventy percent of the sites were over the line on at least a quarter of the days they were tested. Missouri sent the group its data on April 23, 2026.
The report’s named problem waters are Truman Lake in Benton County, Sycamore Creek in Newton County and Grand Glaize Creek in St. Louis County. Those are not Macon County.
The public map that goes with the report is the site list. It has 202 Missouri points. Long Branch L., Long Branch S.P. Public Beach, Macon County, is on it: 30 testing days, 0 days over 190, 0 percent. It is in the clean 31, not the dirty 171.
A Macon County tributary site is in the 171. Middle Fork Little Chariton River at Harvest Road shows 6 testing days and 6 days over the line, 100 percent. The map does not name the main-stem Chariton River as a site.
The report lists sewage overflows, stormwater, manure and failing septic systems as sources of fecal bacteria. It says Missouri needs about $450 million a year for 20 years for wastewater and stormwater work. One federal source sent about $95 million. Those are statewide figures. This story does not invent a Macon sewer or septic dollar.
Labor Day is Monday, Sept. 7. DNR’s weekly sampling runs through that weekend.