Parasite Found In Baltimore-Area Drinking Water, Prompting Warning

BALTIMORE, MD — Low levels of the parasite Cryptosporidium were discovered this week in Druid Lake Reservoir, one of two reservoirs that provide drinking water to Baltimore area, officials said.

According to a release from the Baltimore Department of Public Works, Cryptosporidium is a micro-organism commonly found in lakes and rivers and can cause gastrointestinal problems, especially in children, older adults and people who are immunocompromised.

The warning affects the water supply for Baltimore City as well as Baltimore and Howard counties, officials said.

The affected area is shown in the map below. Residents can also use this interactive map to determine if they live in an affected area.

Officials said Cryptosporidium poses a low risk for the general population, meaning water is still safe to drink. However, those vulnerable to illness should take the following precautions:

• Drink bottled water.
• Boil water for one minute before consuming.
• Filter tap water using a filter labeled to ANSI/NSF 53 or 58 standards, or a filter designed to remove objects 1 micron or larger (i.e. not Brita-type filters.)

The most common symptoms of cryptosporidiosis include diarrhea, vomiting, fever and stomach pain. People with healthy immune systems typically aren't affected and quickly recover without medical treatment.

Examples of people with weakened immune systems include those with HIV/AIDS, those with diseases that affect the immune system, cancer and transplant patients who are taking immunosuppressive drugs.

According to officials, the city will conduct more frequent testing at reservoirs until Cryptosporidium is no longer detected.