Looking at a swimming pool in your neighborhood or at your gym, you can't tell whether you're seeing clean and refreshing water or a reservoir of icky germs.
Pima County Health Department inspectors find a reason to close a public or semi-public pool about 7 percent of the time, usually because of dangerously low or high chemical levels that could make you sick.
When that happens, it's up to the pool owners to fix the problem and report acceptable chemical levels back to inspectors.
Inspectors check 2,500 local swimming pools at least twice a year. Records show inspectors closed pools 446 times in the past year and a half.
Pools with the most problems in recent months are semi-public - those at hotels, apartment complexes, homeowners' associations and gyms.
The county inspects them twice a year.
Pool operators are supposed to check the chemical levels twice a day. However, often when the pool maintenance is contracted out, the water is checked less regularly, which can lead to a chemical imbalance, said inspector Dave Hansen.
In many pool-closure cases, fixes are made the same day or the next day.
When the county closes a pool, pool operators can call the inspector and read the correct levels over the phone to get the OK to reopen, often the same day, Hansen said.
Here are the pools that have failed inspections most often in the past year and a half.
• At JW Marriott Tucson Starr Pass Resort & Spa, 3800 W. Starr Pass Blvd., county health inspectors recorded seven failed inspections during four visits last year, usually because there wasn't enough chlorine.
The resort's engineering director, Mike Hart, said any problems pointed out by inspectors are promptly fixed so facilities are never closed.
The resort passed the most recent inspections in December.
• At Stone Canyon Health & Fitness Club, 14250 N. Hohokam Village Place in Oro Valley, county inspectors recorded seven failed inspections during two visits last year.
In February 2012 the county closed the men's spa, women's spa and lap pool because chlorine levels were too low and pH was too high. And in June 2012 the county closed the men's spa, outdoor spa, lap pool and wading pool because chlorine levels were too high.
Stone Canyon facilities passed their most recent inspections in February.
The club's managers did not return three calls seeking comment.
• At La Vida condo complex, 2601 W. Broadway, county inspectors recorded six failed inspections during four visits last summer and in January because of chlorine levels that were too high or too low.
The complex passed the most recent inspections in January.
The homeowners association board changed its pool maintenance company and has done a lot better since, said Chris Centuori, operations manager and certified pool operator at Arizona Home Owner's Management Experts LLC.
"It's pretty difficult to keep it perfect, and I think they (the Health Department) realize that," he said. "With the heat in the summertime, depending on the usage, I've seen the chlorine go from five to zero in one day."
More enforcement is a good thing, Centuori said, and he credits the county inspectors for good communication with pool operators.
The county inspects public pools monthly during swim season, and pool staff check the water hourly.
Inspectors found a reason to close a public pool only four times in 181 inspections over the past 18 months.
These pools were briefly closed but reopened the same day or the next day.
• Archer Pool, 1665 S. La Cholla Blvd., July 2012.
• Clements Pool, 8155 E. Poinciana Drive, March 2012.
• Palo Verde Pool, 300 S. Mann Ave., two closures in May 2012.
On StarNet: Go to azstarnet.com/databases to find out whether your neighborhood pool passed or failed inspections.
Germs in the pool
A new study of public pools from the Centers for Disease Control and Prevention found some yucky numbers:
• 59: Percentage of water samples with pseudomonas aeruginosa, which can cause skin rashes and ear infections.
• 58: Percentage of water samples with E. coli, a marker for fecal contamination.
• 2: Percentage of water samples with cryptosporidium and giardia, which can cause diarrhea.
"Chlorine and other disinfectants don't kill germs instantly," Michele Hlavsa, chief of the CDC's Healthy Swimming Program, said in a press release.
"That's why it's important for swimmers to protect themselves by not swallowing the water they swim in and to protect others by keeping feces and germs out of the pool by taking a pre-swim shower and not swimming when ill with diarrhea."
Be a pool inspector
Here's what you should check before you and your family take a dip in a public or semi-public pool. Make sure:
• Gates are self-closing and never propped open.
• A ring buoy and shepherd's crook are easily accessible.
• Water is clear, not green or cloudy, and the drain at the bottom is visible.
• And look at the other swimmers. Red or irritated eyes could signal a water-quality problem.
• To report a problem at a semi-public or public pool, call 243-7908.
Contact reporter Becky Pallack at email@example.com or 573-4251. On Twitter @BeckyPallack.