Is Your Building Safe? Baltimore's Legionella Outbreaks Spark New Warnings
- The NuChem Crew
- Jul 16
- 6 min read
Updated: Aug 26
What Is Legionella and Why Is It a Risk?
Legionella is a bacteria found in water that is capable of causing Legionnaires’ disease, a severe form of pneumonia. Humans typically contract it by inhaling tiny water droplets (aerosols) containing the bacteria. Outbreaks often occur via man-made water systems like contaminated cooling towers, faucets, showers, or hot tubs which can spread aerosolized Legionella over a wide area. While healthy individuals may not always fall ill, Legionnaires’ disease can be very dangerous for older adults or those with weakened immune systems, and about one in ten infected people may die. Because Legionella grows best in warm and stagnant water, building water systems that aren’t properly maintained can inadvertently become breeding grounds for this pathogen.
Recent Legionella Outbreaks in Baltimore and Maryland
Over the past year, there have been several confirmed Legionella incidents in Baltimore and surrounding Maryland areas. These incidents have affected a range of facilities from government office buildings to healthcare facilities which emphasizes that no building is immune if water systems are not properly monitored. Below is a summary of key outbreaks and detections reported in the last 12 months, including dates, locations, and impacts:
July 2024 (Baltimore County): Routine testing found Legionella bacteria in water fixtures at two large federal office complexes, the Centers for Medicare & Medicaid Services (CMS) and the Social Security Administration (SSA) headquarters in Woodlawn. Thousands of employees were shifted to remote work out of caution, though no illnesses were reported and both agencies noted no confirmed Legionnaires’ cases among staff. Federal officials attributed the findings partly to pandemic era building low occupancy rates. The resulting stagnant water may have created ideal conditions for Legionella growth.
Fall 2024 (Baltimore City): Multiple Maryland state office buildings in Baltimore’s State Center complex were temporarily shut down in November and December after water samples came back positive for Legionella. The complex, housing state agencies like Health, Labor, and Budget underwent emergency pipe flushing and chlorination. Approximately 4,300 employees were sent home during remediation. No Legionnaires’ disease cases were linked to these buildings but the Maryland Department of Health noted that by late 2024 the state had recorded around 175 Legionnaires’ cases statewide (mostly isolated, individual cases) a slight uptick from the previous year.
December 2024 (Baltimore City): Several Baltimore City government buildings downtown experienced Legionella detections, prompting precautionary closures. In mid-December, three Mitchell Baltimore City courthouses the and Cummings Circuit Courthouses and a civil courts building tested positive for Legionella in their water systems. City officials closed these courthouses for deep cleaning and pipe chlorination over a several day period. Around the same time, City Hall and two other municipal buildings (the Abel Wolman Building and Benton Building) were also found to have elevated Legionella levels. They were closed over a weekend for water system disinfection and later reopened once tests showed the bacteria was cleared. Notably, no confirmed Legionnaires’ disease cases were reported from any of these city building. The closures were “out of an abundance of caution,” as city officials emphasized the mitigation work (flushing and chlorination) itself required shutting off water thus temporarily closing the facilities.
January 2025 (Jessup, MD): A Legionnaires’ disease case was confirmed in an inmate at Dorsey Run Correctional Facility in Jessup (Anne Arundel/Howard County border). The individual developed pneumonia symptoms and tested positive at a hospital; fortunately, he was treated and his condition improved. In response, the correctional facility working with county and state health departments implemented protective measures for staff and other inmates in the same housing unit. “The safety and well-being of our staff and those in our care remain our highest priority,” the Department of Public Safety and Correctional Services stated, confirming they were following all Health Department recommendations to contain the situation. This was one of the few actual illness cases reported in the region over the year, highlighting that even facilities like prisons (with large plumbing systems) are vulnerable to Legionella if water management falters.
February 2025 (Baltimore County): The Maryland Department of Health announced that Spring Grove Hospital Center a psychiatric hospital in the Baltimore area had elevated Legionella levels in parts of its water system. The bacteria was discovered during the facility’s routine annual water testing. Thankfully, no patients or staff were sickened in this case. As a precaution, the hospital temporarily shut down certain water sources (like showers) and installed special filters while carrying out disinfection. “Remediation efforts are underway with shower filters being overnighted so that the showers that are off can be turned back on,” a Maryland Health Department spokesperson said at the time. This incident underscored the importance of vigilant monitoring in healthcare facilities, where immunocompromised patients could face grave risk from Legionella exposure.
April 2025 (Baltimore City): In the spring, the Baltimore City Department of Social Services revealed that its East Biddle Street office complex had isolated areas of Legionella in the water. Proactive water testing begun in January identified the issue, and by late April the building’s water system underwent “shock” chlorination and flushing to eradicate the bacteria. In this case the building remained open with bottled water and hand sanitizer provided, since only a few peripheral locations in the facility showed above-normal bacteria levels. City officials noted that aging plumbing infrastructure could be contributing to recurring Legionella findings in some buildings. In response, Baltimore ramped up water quality checks across many facilities and even upgraded some water treatment systems (adding new corrosion inhibitors and stabilizers) to help prevent bacterial regrowth. Importantly, no Legionnaires’ disease cases were tied to the Biddle Street building or other Baltimore offices – the city’s Health Department confirmed that none of the positive-water tests led to reported human infections.
The past year’s outbreaks in Maryland fortunately resulted in very few actual illnesses, but they served as a wake-up call. From office high-rises and courthouses to hospitals and prisons, the common thread was water systems maintenance (or lack thereof). Each incident was met with aggressive remediation; flushing pipes, shock chlorination, cleaning cooling towers, and temporary closures to eliminate the bacteria. Public health officials repeatedly stressed that these measures were preventive since, in most cases, no confirmed Legionnaires’ cases occurred. However, the disruptions and concern caused by these events highlight that waiting for an outbreak is not an option. The goal is to prevent isolated bacteria detections from ever escalating into multi-person outbreaks.
Legislative and Policy Responses to Baltimore’s Legionella Outbreaks
In response to repeated Legionella detections in government buildings across Baltimore including courthouses, the Department of Social Services, and other state-owned facilities state and local leaders are now considering stronger legislative measures.
In 2022, Maryland lawmakers introduced the Legionnaires’ Disease Prevention Act (Senate Bill 0302, cross‑filed as House Bill 0248), which would mandate that owners/operators of public buildings implement water management programs in alignment with ASHRAE Standard 188 to prevent Legionella growth.
The bill was referred to the Education, Health & Environmental Affairs Committee, with a hearing held on February 2, 2022.
However, the legislative effort stalled in 2022, and no new version has been formally advanced since. Advocates believe that the overlooked outbreaks in Baltimore especially mass testing that revealed Legionella in 15 state and municipal buildings between July 2024 and March 2025, could spur renewed momentum .
Local Advocacy in Baltimore City
Baltimore City Council is exploring citywide mandates requiring periodic Legionella water testing and management plans for public buildings. Councilman Zachary Blanchard has stated that the current system is “reactive only” and is open to policy changes.
The Baltimore City Circuit Court Clerk’s Office, following the detection of Legionella in key courthouses in December 2024 and February 2025, urged for a “routine water quality maintenance plan” and called out the shortcomings of “Band‑Aid tactics”.
The Alliance to Prevent Legionnaires’ Disease, a nonprofit advocacy group, is preparing to draft legislation modeled after New Jersey’s comprehensive Legionella law spanning from water source to taps targeted for upcoming Maryland legislative sessions. They intend to secure sponsorship from state lawmakers soon.
Despite heightened problems there remains no binding state-level regulation for Legionella testing or remediation. Maryland currently lacks enforceable standards, relying instead on voluntary frameworks like ASHRAE 188 and guidance from the Centers for Medicare & Medicaid Services. Advocates and public health experts argue that legislation is needed to mandate consistent testing, risk-based water management, and transparency in publicly used buildings echoing regulations now found in states like New York and New Jersey.
Don’t wait for Legionella to make headlines in your building. Act now to ensure your water systems are safe. Contact NuChem Corp today for a consultation. Our professional team will develop a customized Building Management Program or Legionella prevention program that fits your facility and keeps you in control of water safety. In the wake of the Baltimore outbreaks, the message is clear: vigilance and prevention are non-negotiable. Let NuChem Corp partner with you to implement these life saving measures. Together, we can protect your tenants, employees, patients, or residents and ensure that Legionella stays out of your water and out of the news.
Be proactive, be prepared, and you’ll be safeguarding not just your facility’s compliance, but the health of everyone who walks through its doors.
Protect your building and its people from Legionella - contact NuChem Corp to get started on a water safety plan today.
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