Owners/Operators of Public Pools Located in the County of Orange
Procedures Following the Contamination of a Public Pool by Feces,
Vomitus or Dead Animals
Microorganisms, such as Cryptosporidium, E. coli 0157:H7, and Giardia
have been linked to waterborne outbreaks at public pool facilities.
The 1998 outbreak of E. coli 0157:H7 illness associated with a fecal
contamination of a public pool at a waterpark in Georgia reinforces
the seriousness of these situations. The strain of E. coli associated
with the waterpark outbreak is the same one that was associated
with contaminated hamburger patties at a chain of fast food restaurants.
These diseases are caused by the consumption of water or food that
has been contaminated with human or animal fecal matter or human
vomitus that contains these microorganisms.
The effects of feces, vomitus or a dead animal in a public pool
can be serious, if not life-threatening to pool users especially
children, the elderly and people with suppressed immune systems.
Feces and vomitus material can contain large numbers of pathogenic
(harmful) microorganisms. If an animal enters the pool and dies
it voids its bowels releasing pathogens into the pool water.
The following are some requirements and recommendations that, when
implemented, can reduce the possibility of contracting a waterborne
illness from a pool:
the pool water chemistry in balance and proper levels of disinfectant
pool should not be used unless the filtration system is in good
wearing only diapers in the pool, changing of diapers at poolside,
or washing off soiled infants in the pool water should be prohibited.
who are not toilet trained or anyone who is incontinent should
not use the pool. If incontinent individuals are allowed to
use the pool, rubber pants, "swim diapers" or special
swimsuits should be worn. These items have some ability to contain
fecal material and may afford only limited protection.
users should wash their hands with soap and hot water after
using the toilet.
users should take a shower before entering the pool.
users who are suffering from a communicable disease that can be
transmitted through water or who have had diarrhea in the past two
weeks should not use the pool.
If feces, vomitus or a dead animal is found in a pool, the following
steps must be immediately implemented:
all pool users to exit the pool(s) immediately. Do not allow
anyone to enter the contaminated pool until all of the following
steps are completed.
as much of the fecal material as possible using a net or scoop
and dispose of it in a sanitary manner. Clean and disinfect
the net or scoop (e.g., after cleaning, leave the net or scoop
immersed in the pool during the disinfection period). Vacuuming
stool from the pool is not recommended. If the pool is vacuumed,
waste should be directed to a sanitary sewer and not through
the filtration system.
If the fecal accident involves a formed stool (solid, not liquid)
or vomitus is found in the pool - raise the free available
chlorine concentration to 2 parts per million (ppm) and maintain
the pH between 7.2 - 7.5 for at least 25 minutes. If a free
available chlorine concentration of 3 ppm is present, the time
can be reduced to 19 minutes.
b. If the fecal accident involves diarrhea or a loose stool
or if a dead animal is found in the pool - raise the free
available chlorine concentration to 20 ppm and maintain the
pH between 7.2 and 7.5 for at least 8 hours. This is equivalent
to a Concentration/Time (CT) value of 9,600. The CT value is
the concentration of chlorine in ppm multiplied by the time
in minutes and is used to determine the point at which Cryptosporidium
oocysts are inactivated. In this case, a 20 ppm concentration
of chlorine maintained in a pool for 8 hours or 480 minutes
will result in a CT value of 9,600 (480 minutes X 20 ppm). Any
combination of chlorine concentration and time resulting in
a CT value of 9,600 or greater can be used to achieve disinfection.
For fecal accidents involving diarrhea or loose stools, the
filter should be thoroughly backwashed to a sanitary sewer after
the CT value has been reached and before the pool is reopened.
the entire treatment period, ensure that the pH is maintained
between 7.2 and 7.5. The pH may be affected if additional chlorine
is added to the pool.
that the filtration system is operating and the proper free
available chlorine concentration is maintained throughout the
treatment period. Ensure that free available chlorine concentrations
are found throughout all areas of the pool or co-circulating
pools by sampling in at least three widely spaced locations
away from return water inlets.
pool may be reopened after the required time/concentration or
CT value has been achieved and the free available chlorine residual
is below 5.0 ppm.
the pool is a low water volume pool, such as a spa pool or wading
pool, the pool can be drained. The pool should be refilled,
the water balanced and the proper CT value achieved before being
Establish a fecal accident log. Document each fecal accident
by recording the following information:
and time of the event
stool or diarrhea
available chlorine concentration and pH at the time of observation
of the event
available chlorine and pH before reopening the pool
Procedures followed to respond to the fecal accident, including
the process used to increase the free chlorine residual
accident pool closure procedures are based on recommendations
by the Centers for Disease Control and Prevention.
contact times assume a water temperature of 25°C (77°F).
Theoretical Pool Closure Times for 99.9% Inactivation of Giardia
Cysts by Free Available Chlorine, pH 7.5, 25°C derived from
the EPA's Disinfection Profiling and Benchmarking Guidance Manual.
short pool closure time is the chlorine concentration/contact
time theoretically required to inactivate Giardia cysts. The
long pool closure time is the chlorine concentration/contact
time theoretically required to inactivate Cryptosporidium oocysts.
Chlorine disinfectants are not addressed and should not be used
because there is limited pathogen inactivation data available
for these compounds.
impact of chlorine stabilizers such as chlorinated isocyanurates
on pathogen inactivation and disinfection measurement is unclear
and warrants further investigation. Increased contact time may
conventional test kits cannot measure free available chlorine
in a range that includes 20 ppm. In this case, use chlorine
test strips, kits that can measure in this range, or make dilutions
using a standard DPD (N,N-diethyl-p-phenylenediamine) test kit
and chlorine-free water.
levels of chlorine may damage pool equipment. Exercise caution or
consult with an experienced aquatic professional.