How Safe is Our Drinking Water?

Q:  Some friends and I were recently discussing the great Milwaukee cryptosporidium outbreak of the early 90s and started to wonder:

How safe is our drinking water these days?

If you use water to make drip coffee, could you get sick from it? (I'd guess the answer is yes.)

Could you get crypto from drinking beer? (My guess is no.)

A:  Cryptosporidium ("crypto") is a parasite that lives in the intestines of infected humans and animals. Its eggs are passed in stool, so we can pick up crypto from soil, food, water, or surfaces that have been in touch with the feces. We become infected by swallowing the parasite.

Symptoms can start from 2 to 10 days after contact with the parasite. In generally healthy people, symptoms include diarrhea, loose or watery stools, stomach cramps, upset stomach or vomiting, and a slight fever. These usually last about 2 weeks and may go in cycles in which the illness seems to go away for a few days, then comes back. Some people have no symptoms.

Unlike healthier people, crypto is very dangerous for those with immune system deficiencies from conditions such as HIV/AIDS, cancer or leukemia, or from treatments such as chemotherapy or steroid therapy that suppress the body's natural immunity. Immune-compromised patients can get severe, chronic diarrhea with weight loss and abdominal pain.

No specific treatment exists for "crypto," so patients must be careful not to get dehydrated while they wait it out.

As a result of the 1993 crypto outbreak that put Milwaukee on the national map, we now have the most monitored water in the US, according to Paul W. Nannis, the Commissioner of Health for the city health department. He told me that the health and water departments have extensive protocols for reviewing water quality parameters, and the Milwaukee Health Department has its own crypto lab (one of the few cities that does) for regular water monitoring.

The city also installed state-of-the-art turbidity monitors and particle counters at our two water treatment plants. Another important change was the movement of the intake "crib" (which pulls in Lake Michigan water) to a point one mile further out than it was previously. This should ensure that no water from the three rivers that flow into the lake gets pulled into our plants.

Lastly, Mr. Nannis told me that the improved plants will now use ozone as the disinfection agent. The crypto parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine disinfection; ozone is the only known agent that kills crypto to within limits that are safe for humans.

As for your last two questions, you're batting 500. A coffee maker will kill crypto if the water gets above 140 degrees. Beer is pasteurized and this process also kills crypto.

"Dear Doctor" is a compilation of patient questions answered by doctors from the Medical College of Wisconsin.