Despite low bacteria levels found Monday, the Florida Department of Health in Martin County is still warning people to stay out of the St. Lucie River around the Roosevelt Bridge in Stuart and Leighton Park in Palm City.

Department officials want to see two consecutive readings with low counts of enteric bacteria at the sites before giving the all clear, said Todd Reinhold, environmental health manager at the Martin County office.

The next sampling is scheduled for Monday.

"If both sites come back with acceptable (bacteria) levels Monday, we'll lift the advisory," Reinhold said.

Enteric bacteria inhabit the intestinal tracts of humans and animals, and their presence in recreational waters is an indication of fecal pollution from stormwater runoff, pets, wildlife and human sewage.

Swallowing or coming in contact with contaminated water can cause upset stomach, diarrhea, eye irritations and skin rashes.

Health department officials suspect heavy rains last weekend washed the bacteria into the water.

The department issued the warning Friday after water samples taken at the two sites Jan. 28 and 30 had high levels of bacteria.

More:Health advisory issued at 2 sites in St. Lucie River

The health department considers levels above 70 enteric bacteria colonies in a 100-milliliter water sample to be unsafe. Samples had bacteria levels of:

Leighton Park: 624 on Jan. 28, 164 on Jan. 30

624 on Jan. 28, 164 on Jan. 30 Roosevelt Bridge: 111 on Jan. 28, 137 on Jan. 30

Monday's results were:

Leighton Park: 31

31 Roosevelt Bridge: 10

The department also conducts weekly water sampling in the St. Lucie River at Sandsprit Park near Port Salerno and in the Indian River Lagoon at the Stuart Sandbar between Sewall's Point and Sailfish Point.

Both those sites had bacteria counts Monday of 10 colonies per 100 milliliters of water.

A similar warning was issued last week at three ocean beaches in Vero Beach. The state Health Department in Indian River County lifted the warning Tuesday after a single round of acceptable bacteria levels.

More: Health department lifts bacteria warning at 3 Indian River County beaches

How's the water?: Check on the status of the water near you with our interactive map. Note: The map will not reflect new advisories until an auto-update at 5 p.m.