

Chief State Medical Examiner
PO Box 360 March 27, 2023 |
Judith M. Persichilli |
As part of an ongoing investigation by the New Jersey Department of Health (NJDOH) into Legionnaires’ disease among residents in Mercer County in areas served by Trenton Water Works (TWW), seven cases of Legionnaires’ disease have been reported between October 2022 and March 2023. The seven cases occurred in Trenton, Ewing Township, Lawrence Township, and Hamilton Township. Of the seven, two individuals have died.
Health officials from NJDOH have briefed elected representatives at the local and State level on this matter and will continue to collaborate with them throughout this ongoing investigation.
NJDOH continues to urge all residents and building owners who receive water from TWW to follow the recommendations outlined below to reduce the risk of Legionella growth, the bacteria that causes Legionnaires’ disease, in their household and building premise plumbing. Residents who do not know their water utility company can check their water bills; renters can ask their property owners.
While it remains rare for a healthy person who is exposed to Legionella to become sick with Legionnaires’ disease, people who are 50 years or older, especially those who smoke, or those with certain medical conditions, including weakened immune systems, chronic lung disease or other chronic health conditions, are at increased risk. It is not known if individuals with Legionella detected in their homes are more likely to develop Legionnaires’ disease.
Legionnaires’ disease is a type of pneumonia (lung infection) that people can get after breathing in aerosolized water (small droplets of water in the air) containing Legionella bacteria. People cannot get Legionnaires’ disease by drinking water that has Legionella. Less commonly, people can get sick when water containing Legionella is aspirated into the lungs while drinking (“goes down the wrong pipe”).
Symptoms of Legionnaires’ disease include cough, shortness of breath, fever, muscle aches, and headaches, which are similar to symptoms caused by other respiratory infections, including COVID-19. Legionnaires’ disease can be fatal but is treatable with antibiotics. It is important for anyone who thinks they have symptoms of Legionnaires’ disease to contact their health care provider and seek medical evaluation immediately.
Health officials continue to urge health care providers to collect lower respiratory specimens for Legionella PCR and/or culture, in conjunction with use of the urinary antigen test, when suspecting Legionnaires’ disease. This is especially important among residents who receive water from TWW. The urinary antigen test is the most common diagnostic method but can only detect Legionella pneumophila serogroup 1. PCR and culture of lower respiratory specimens can detect all Legionella species and serogroups.
NJDOH continues to partner with the New Jersey Department of Environmental Protection (NJDEP) and the affected local health departments to investigate factors that may be promoting the growth of Legionella bacteria and evaluate remedial actions that can be taken to improve water quality and reduce Legionella in the water system.
In accordance with its October 12, 2022 Unilateral Administrative Order, which provides NJDEP direct operational oversight authority, NJDEP has been working with TWW to implement strategies to optimize operation of the treatment plant and the distribution system. To help address Legionella in its water system, TWW will initiate a low-velocity flushing program throughout its service area in early April 2023 to increase the water circulation throughout the distribution system, and to increase and optimize chlorine levels. Low-velocity, or conventional flushing, restricts the hydrant flow to such levels that the sediment within the pipes is not disturbed or scoured. The goal is to optimize chlorine disinfection to minimize the conditions that contribute to the growth of pathogens, such as Legionella.
TWW employees will be working throughout TWW’s service area to sample or flush hydrants using specific assemblies that will keep hydrant flows at the necessary velocities. It is not expected that customers will experience noticeable water quality changes, such as discoloration, in their home or business through the duration of this program. TWW will also notify customers when flushing activities are occurring in their service areas.
TWW customers on home dialysis should contact their kidney specialist to check if additional testing of water for chlorine residual, or any other measures, is required before use. Additionally, customers using tap water for aquariums should monitor the chlorine residual levels before use and treat as needed.
Residents are encouraged to contact TWW at (609) 989-3208 or the NJDEP Bureau of Safe Drinking Water at (609) 292-5550 with any questions or comments, or visit dep.nj.gov/trentonwater.
NJDOH receives approximately 250-350 reports of Legionnaires’ disease each year throughout New Jersey. Cases of Legionnaires’ disease are more common during warmer months than during colder ones. Frequently Asked Questions on Legionnaires’ disease can be found on the NJDOH website.
HOW TO DECREASE RISKS OF LEGIONELLA EXPOSURE
According to NJDOH, individuals, particularly those at high risk, can follow the recommended steps below to decrease the risk of Legionella exposure and best practices to limit the growth of Legionella in household water systems and devices:
RECOMMENDED ACTIONS FOR BUILDING OWNERS