When there's poo in the pool, it's everybody's problem.

That was the message Thursday from the Utah County Health Department. Officials were at the Springville Community Pool to show just how quickly bacteria can spread in the water. Standing at the edge of the diving board, environmental health program manager Jason Garret dumped a small load of a dye called methylene blue into the deep end of the pool. Within minutes, the dye had spread across a quarter of the pool's surface and several feet below.

"This is simulating what's referred to as a fecal accident," department spokesman Lance Madigan said as the dye spiraled languidly through the water. "A single fecal release releases millions of spores. It only takes like 10 to make somebody sick."

The spores Madigan was referring to are of the bacteria cryptosporidium. If swallowed with pool water, they can sicken a person for weeks with symptoms including what the department calls "explosive diarrhea."

The department was illustrating the point that although new ultraviolet disinfectant systems provide health officials with a new tool in the fight against contamination -- they call it "sunburn in a can," because it basically fries each individual bacterium to death -- it takes a while for the water to circulate through the system.

"Everybody thinks UV rays are like a magic bullet," Madigan said. "It doesn't magically disappear. You can see it takes a little while for it to spread."

In fact, water must circulate through the system three times before officials are confident the bacteria has been purged -- a process that can take 12-18 hours, said Ron Tobler, another environmental health program manager.

"All the water that we're getting clean mixes right back in with the dirty water," he said. The first run removes about 65 percent of bacteria from the pool, he said.

Tobler said depending on the flow of the pool, sometimes pockets of bacteria can form on their way to the filters and UV system. In Springville, clouds of dark blue water congealed in places along the side of the pool.

"It goes right down that path where people hold onto," he said. "There's a lot of people who would swim through that."

That's why it's county policy to pull everyone out of the pool and shut it down for cleaning if a watery discharge is discovered, Tobler said. Accidents of more solid constitution generally don't suggest illness and require a shorter evacuation. But it's the more dangerous releases that are harder to find, he said.

"It becomes profoundly difficult," Tobler said. "When it comes to crypto, most of this is watery stool."

Tobler said the best countermeasure to bacterial infection is action beforehand -- something too few people did last summer. About 2,000 cases of cryptosporidiosis -- the condition resulting from infection -- were reported in Utah between June and December 2007, including about 450 in Utah County.

"It really was by all definitions an epidemic," he said. "There was enough infection early in the year to gain momentum and take off on its own."

For starters, Tobler said, don't go swimming in any public areas within two weeks of being sick. It's not enough to feel well on the given day you want to swim, he said.

"As soon as people feel better, they assume they are better," he said.

The county also recommends showering before swimming, washing with soap after using the restroom or changing a diaper, and keeping kids who aren't potty-trained in swim diapers.

But UV can help, said Springville facilities manager Shaun Orton. It's quicker and less expensive than the conventional means of containing a bacterial outbreak -- pumping eight times the normal amount of chlorine into pools for 18-hour periods twice a week afterward.

"With a UV system, swimmers could be in the pool the next morning," he said.

The Springville pool should be getting its UV system installed in time for Memorial Day, Orton said. Other cities in Utah County, like Provo and Orem, are also in various stages of installing the systems in their public pools.