Proper water-heater temperature.(Letters)(Letter to the editor)

In your June issue, plumbing contractor Dave Yates makes a comment I find very hard to believe (Q&A, 6/06). He states, "Estimates of the number of deaths from potable hot-water system bacterial infections range widely, but 10,000 per year is the middle ground."

The article does not state whether 10,000 per year is an estimate for the United States or for the entire world, but either way, this number seems unbelievably high to me. Please elaborate if you have any more information on the subject.

Gary Dresser

Dresser Homes

Atlanta

Dave Yates responds: Actually, I suspect that the number is low, but others who look at the same data might arrive at a different conclusion. My estimate is based mostly on statistics concerning legionellosis, or Legionnaires' disease (LD), a pneumonialike illness caused when water droplets containing legionella bacteria are inhaled or aspirated.

In the United States, fewer than 2,000 official cases of LD are reported each year, but the national Centers for Disease Control and Prevention estimates that between 8,000 and 18,000 Americans are infected with the disease annually. Many more cases, CDC scientists say, are not reported or are misdiagnosed. For example, some researchers believe that anywhere from 2 percent to 15 percent of the 600,000 patients who enter hospitals each year with community-acquired pneumonia actually have LD.