AWWA FACT SHEET
Cryptosporidium

Cryptosporidium (sometimes called “crypto”) is a protozoan parasite that lives and
reproduces in the intestines of mammals, including humans.

Cryptosporidium gets into the water supply from the fecal material of infected
mammals, including livestock. Research indicates that Cryptosporidium is present in
95 percent of all surface water sources in America.

Cryptosporidium enters the water supply prior to maturity. Early in its development,
Cryptosporidium is encased in a tough outer shell, which makes it impervious to
chlorine disinfection -- the traditional and most common method of disinfection for
American drinking water supplies.

Infection by a specific strain of Cryptosporidium, known as Cryptosporidium parvum,
causes the disease cryptosporidiosis in humans. The symptoms of cryptosporidiosis
include stomach cramps and diarrhea. There is no cure; however, people with healthy
immune systems will recover naturally after approximately 14 days. For individuals
who have weakened immune systems, such as those infected with HIV, the disease
can be fatal.

Cryptosporidium outbreaks are a relatively new problem for the U.S. According to
the Center for Disease Control, instances of outbreaks worldwide were rare prior to
1982. To date, only 6 recognized outbreaks attributed to drinking water have
occurred nationwide.

In 1993, the largest recognized Cryptosporidium outbreak stemming from
contaminated drinking water occurred in Milwaukee. In that episode, an estimated
400,000 people became sick and 40 deaths were attributed to cryptosporidiosis. The
Milwaukee outbreak raised awareness of the need to find effective treatment methods
for Cryptosporidium contamination.

Due to Cryptosporidium’s relatively recent emergence, it was not originally listed as
a contaminant under the Safe Drinking Water Act. However in 1994, the U.S.
Environmental Protection Agency (USEPA) proposed the Interim Enhanced Surface
Water Treatment Rule (IESWTR) which established a goal of zeroing out
Cryptosporidium concentration in drinking water.

The Safe Drinking Water Act Amendments of 1996 required USEPA to promulgate
the IESWTR by November 1998.

In December 1998, USEPA issued the final IESWTR. The rule included the initial
goal of zeroing out Cryptosporidium concentration levels and also required 99% of
Cryptosporidium to be removed by systems already required to filter by federal law.
In addition, the rule required all new finished reservoirs to be fitted for covers. The
rule also sought to address the reality that monitoring water supplies for
Cryptosporidium is very difficult, requiring a 60 percent reduction in turbidity for
finished water.

In November, 2000, USEPA reached agreement with stakeholders –including
AWWA—on more stringent cryptosporidium protections for community water
supplies. Under the agreement, water providers will:
1. increase monitoring for Cryptosporidium
2. produce a removal plan drawing from a number of options, such as improved
source water protection, alternative disinfection methods and more thorough
filtration.

AWWA estimates the rule will cost water utilities over $5 billion in capital
investments and $300 million annually in operations costs.