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CLEVELAND (WJW) — Northeast Ohio Regional Sewer District officials on Friday again warned swimmers of heightened bacteria levels at a Lake Erie beach.

Another local beach was closed Friday after sewage overflowed near the swimming area, due to a recent storm.

Water quality at Edgewater Beach and Villa Angela Beach is expected to be poor on Friday, July 18, due to a recent combined sewer overflow near the swimming area and concentrations of E. coli predicted by virtual modeling technology, according to a Friday news release from the sewer district.

Combined sewer systems — commonly designed in the 19th century — carry sewage as well as stormwater runoff and are designed to overflow in periods of heavy rain and discharge into nearby water bodies at certain points, called combined sewer overflows, or CSOs.

Edgewater Beach was closed on Friday due to the sewage overflow, according to the Cleveland Metroparks. The district first issued an alert on Thursday.

Villa Angela Beach on Friday was predicted to have an E. coli concentration of 209 most probable number of organisms per 100 milliliters, or MPN/100mL. The E. coli threshold for that beach is 110 MPN/100mL, according to the district.

The E. coli level there is down from Thursday, July 17, when it shot up to 1,622 MPN/100mL, according to data from the U.S. Geological Survey.

E. coli is an infectious bacteria that can cause bloody or watery diarrhea, severe stomach cramps, vomiting or a low fever, according to the U.S. Centers for Disease Control and Prevention.

The district uses virtual modeling technology to predict whether bacteria levels will exceed the threshold, and that modeling tends to underestimate the concentration, according to the release. For Villa Angela Beach, the probability bacteria would exceed the threshold was above 68% on Friday.

Bacteria advisories are not an indicator of whether a beach will be closed. To find out, visit the Cleveland Metroparks website.