7,400 gallons of wastewater spilled into John’s Pass. An abandoned shovel is to blame.

UPDATE: Pinellas County said Friday the latest water quality samples showed water around John’s Pass was safe to swim in again, according to spokesperson Sydney Criteser.

MADEIRA BEACH — Enough dirty water to fill nearly 200 bathtubs was emptied into John’s Pass Tuesday night — and county utility officials say an abandoned shovel is to blame.

An estimated 7,400 gallons of untreated wastewater spilled into the channel that separates Treasure Island and Madeira Beach after a shovel was left in a manhole, according to Michele Duggan, utilities compliance manager for Pinellas County Utilities. The shovel likely blocked the wastewater that flowed from nearby businesses on the John’s Pass boardwalk, and the water had nowhere to go but out.

Of the four water samples the county received Thursday from around John’s Pass, two showed overly high bacteria levels, according to county spokesperson Sydney Criteser. That means “the area is not yet cleared to resume recreational activities,” she said in a statement to the Tampa Bay Times. The county was still collecting more water samples as of Thursday afternoon.

The spill lasted nearly 3½ hours, beginning just after 6 p.m. Tuesday, according to an initial pollution notice the county submitted to the Florida Department of Environmental Protection Wednesday morning.

It’s currently unclear who left behind the shovel, Duggan said. The county is working on piecing together a more detailed pollution report, and the state is investigating the spill, according to spokesperson Alexandra Kuchta.

Water first flowed into a nearby storm drain, then emptied into John’s Pass, Duggan said. The county put out three warning signs urging the public to stay out of the water: one upstream of the spill, one downstream and a third at the spot where wastewater empties from the drain into the waterway. Because water samples showed higher-than-normal bacteria levels, the signs will remain posted until the water improves, Criteser said.

“We are out there sampling until we feel it’s resolved,” Duggan said Wednesday. “We’ll let nature do its thing. It will clear up. It’s windy out there today.”

Wind can help to break up densely concentrated wastewater spills.

It was blowing at 16 mph in Madeira Beach on Wednesday and 11 mph on Thursday, weather data shows.

A 7,400-gallon spill pales in comparison to some recent local wastewater spills reported to the state — but this one directly impacted a waterway. On Feb. 12, for instance, nearly 130,000 gallons of untreated wastewater were emptied into a rural Wesley Chapel field and roadway after a pipe broke, state pollution reports show. No waterways were impacted in that spill and there were no potential public health risks.