No matter how conscientious you are as a pool/spa operator, the time will come when you’ll need to deal with some type of emergency at your facility.

When it comes to water quality, a number of different emergencies are possible, but a few specific ones elicit the most concern. These include organic matter contamination (a fecal accident, blood or vomit), broken glass and water chemistry issues such as excessively high chlorine.

Opinions may differ on how to respond to these situations, but the underlying premise is, and must remain, protecting the health of the patrons and staff. With this in mind, here are generally accepted responses to these situations.


According to the Centers for Disease Control and Prevention, fecal contamination of recreational waters is on the rise. Outbreaks in man-made venues have seen the greatest increase, a result of people swimming with infectious, diarrhea-causing pathogens. Contamination from solid stools also is a problem. If you are faced with a fecal incident:

  • Close the pool immediately.
  • Remove contaminating material and dispose of properly. DO NOT use a vacuum to remove contaminants.
  • Properly clean and disinfect the equipment used for removal of the contaminants.
  • Properly clean any contaminated surfaces, such as pool walls, and disinfect with a 5,000 ppm bleach solution or equivalent. Disinfectant contact time on the affected area needs to be a minimum of 20 minutes, or as otherwise indicated on the disinfectant label.
  • Check the water quality. Verify a stable water temperature of 77 degrees Fahrenheit or above, and pH of 7.5 or less. Adjust if necessary.
  • Operate the recirculation system while the pool reaches and maintains the required free chlorine concentration.

For fecal accidents involving solid stools, the free chlorine residual needs to be raised to 2.0 ppm, and maintained for a period of at least 25 minutes.
For fecal accidents involving diarrhea, the free chlorine residual needs to be raised to 20.0 ppm, and maintained for a period of at least 12.75 hours.

Take free chlorine readings at various locations in the pool to ensure proper chlorine concentrations throughout.

Fecal accidents in pools using chlorine stabilizers such as cyanuric acid (which slows disinfection) need additional attention. For such pools, the pH should be lowered to 6.5, and the free chlorine residual raised to 40.0 ppm. These parameters need to be maintained for at least 30 hours. Facilities using bromine as a disinfectant should follow the same procedures and chlorine concentration as specified for a chlorinated pool.

When a pool or spa is contaminated by vomit, follow the same procedures described for fecal contamination. The chlorine concentration and contact time should be the same as that for solid feces contamination.

Though there is concern about bloodborne pathogens, there is no public health reason to recommend closing a pool due to blood contamination. Data suggests that the risk from bloodborne pathogens is greatly diminished through dilution and normal chlorine residual levels. This does not prohibit the operator from closing the pool temporarily due to aesthetic concerns.

In blood-contaminated water, the chlorine level should be checked. If it is below the required concentration, the affected area or feature should be closed until the chlorine residual is verified at or above the required level.


Broken glass is very difficult to clean up thoroughly. The hard surfaces in and around pools cause glass to shatter, with large chunks and tiny pieces landing everywhere, including in the pool.

If broken glass lands in the pool, it becomes more dangerous and difficult to clean up. The proper response to such accidents obviously depends upon the extent of the contamination. Generally, you should consider the following steps:

  • Carefully remove all larger pieces on the deck area using a broom and/or “shop-type” vacuum.
  • Vacuum the pool bottom. Depending upon the potential contamination, you may wish to drain the pool first.

    You can minimize the potential for water chemistry issues with careful and frequent monitoring, but sometimes such issues are unavoidable. Problems include too much or too little disinfectant, algae, and colored or cloudy water. Addressing each of these problems requires a unique approach.

     Too much disinfectant can negatively affect other water quality parameters, and create potential respiratory health issues. Correct quantities of disinfectant, as well as careful monitoring of the disinfectant level, are key to minimizing such occurrences. If the chlorine level exceeds requirements, it can be neutralized by adding sodium thiosulfate to the water.

    Algae is usually not harmful to swimmers, but it can cause discoloration and staining of the pool walls. Chlorine and bromine disinfectants kill algae, so it is important to maintain these disinfectants at the required levels. There are also chemicals on the market that can help kill and remove algae from pool surfaces.

    Colored water can occur when chemicals such as iron and copper are present in excess in the pool water. The reddish-brown color resulting from too much iron can result from erosion/corrosion of pumps and other iron-containing equipment. A greenish color, resulting from too much copper in the water, also may be due to corrosion of metal from low pH.

    Maintaining proper levels of water disinfectants and pH  can minimize colored water issues. Removal of color resulting from these problems can be achieved through the use of chelating or sequestering agents, which bind up the metal in the water, allowing it to be filtered or vacuumed out.

    About the Instructor

    Jim Dingman has been employed by Underwriters Laboratories in Northbrook, Ill., since 1998. He is a lead regulatory engineer in the Regulatory Services Department, coordinating regulatory activities for UL’s Environmental & Public Health programs, including drinking water additives and system components, food safety, and pool equipment.