Sounds about right in that sewer.
Does anyone notice?
WIKI
Over 90% of cases of Legionnaires’ disease are caused by Legionella pneumophila.
Temperatures above 60 °C (140 °F) kill the bacteria.
Before 1988, energy conservation programs from the late 1970s and early 1980s still mandated a maximum hot water generation, storage, and distribution temperature of 110 °F (43 °C), unknowingly Legionella bacteria’s ideal breeding temperature. To minimize risks of bacterial growth, the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ 1988 ASHRAE Standard 188 and subsequent ASHRAE Guideline 12-2000 increased recommended hot water generation and storage temperatures to 135–140 °F (57–60 °C) with minimum distribution temperatures of 124 °F (51 °C).
Although the risk of Legionnaires’ disease being spread by large-scale water systems cannot be eliminated, it can be greatly reduced by writing and enforcing a highly detailed, systematic water safety plan appropriate for the specific facility involved (office building, hospital, hotel, spa, cruise ship, etc.)
Some of the elements that such a plan may include are:
Keep water temperature either below or above the 20–55 °C (68–131 °F) range in which the Legionella bacterium thrives.
Prevent stagnation, for example, by removing from a network of pipes any sections that have no outlet (dead ends). Where stagnation is unavoidable, as when a wing of a hotel is closed for the off-season, remedial measures are recommended, e.g., maintaining elevated temperatures throughout the hot-water distribution system and periodic disinfection or permanent chlorination of cold-water systems.
Prevention of biofilms is crucial because once established they become more difficult to remove from piping systems. The likelihood of formation is increased by pipe scale and corrosion; warm water temperatures; stagnation and the quantity of nutrients that enter the system.
Periodically disinfect the system, by high heat or a chemical biocide, and use chlorination where appropriate. Monochloramine is likely more effective than free chlorine (sodium hypochlorite), being more resistant with residuals likely to persist to the point of delivery. Monochloramine is also more likely to penetrate legionella biofilms.
L. pneumophila thrives in aquatic systems, where it is established within amoebae in a symbiotic relationship. Legionella bacteria survive in water as intracellular parasites of water-dwelling protozoa, such as amoebae. Amoebae are often part of biofilms, and once Legionella and infected amoebae are protected within a biofilm, they are particularly difficult to destroy.
In the built environment, central air conditioning systems in office buildings, hotels, and hospitals are sources of contaminated water.
Other places the bacteria can dwell include cooling towers used in industrial cooling systems, evaporative coolers, nebulizers, humidifiers, whirlpool spas, hot water systems, showers, windshield washers, fountains, room-air humidifiers, ice-making machines, and misting systems typically found in grocery-store produce sections
https://en.wikipedia.org/wiki/Legionnaires%27_disease
I remember when it was first discovered and given the name. Members of the American Legion in 1976 had their yearly convention at the Bellevue-Stratford Hotel in Philadelphia. I recall they linked it to pigeon droppings.
Drama explodes at Billionaires’ Row tower as wealthy homeowners sue for ‘chalky’ water coming from the faucets