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Legionella · Hospitals, clinics and frail care · Water safety
Key facts
- Caught in healthcare about 1 in 4 die (CDC)
- US outbreaks 2000 to 2014 healthcare had 85 percent of the deaths
- Hot water at outlets at least 55 °C within one minute
- Hot water returns at least 55 °C on every loop
- South African floor GN 7779 (8.2.9): hot water above 50 °C, cold below 20 °C in health establishments
- Stored cold water no more than 12 hours’ use
- Any Legionella detected corrective action (enHealth)
- Nebulisers sterile water to rinse and fill (CDC)
- Scalding fit and test TMVs first, then raise storage to 60 °C
For the person who signs off the water plan
Legionella Responsible Person Training covers the healthcare limits, the any-detection rule, TMVs, nebulisers and a frail care incident you work through step by step. Ten hours online, R2 950, HPCSA CPD accredited.
Why is Legionella more dangerous in hospitals and frail care?
The people at higher risk are the people healthcare buildings exist for. The CDC lists people aged 50 or over, current or former smokers, and people with chronic lung disease such as COPD, a weakened immune system, cancer, diabetes, kidney failure or liver failure.
The numbers follow. The CDC puts the case fatality at about 1 in 10 overall and about 1 in 4 when the disease is acquired during a healthcare stay. The WHO’s 2007 review gives an attack rate of 0.1 to 5 percent in the general population against 0.4 to 14 percent in hospitals. The WHO also puts the case fatality at 40 to 80 percent in untreated immunosuppressed patients.
South Africa has its own evidence. NICD sentinel surveillance at Klerksdorp-Tshepong and Edendale hospitals from 2012 to 2014 found Legionella in 21 of 1 805 patients (1.2 percent) with severe respiratory illness. Most had HIV and/or TB, and 4 of the 21 died. A case published in 2017 linked a two-week-old baby’s L. pneumophila serogroup 1 infection, by whole genome sequencing, to a hospital water system. More in our guide to Legionnaires’ disease in South Africa.
What do outbreak investigations say about healthcare?
| Finding | Figure | Source |
|---|---|---|
| US outbreaks investigated, 2000 to 2014 | 27 outbreaks, 415 cases, 65 deaths | CDC Vital Signs, 2016 |
| Outbreaks in long-term care | 5 of 27 (19 percent) | CDC Vital Signs, 2016 |
| Outbreaks in hospitals | 4 of 27 (15 percent) | CDC Vital Signs, 2016 |
| Outbreak deaths in healthcare settings | 85 percent | CDC Vital Signs, 2016 |
| Outbreaks with problems a water management programme could have prevented | 23 of 27 (85 percent) | CDC Vital Signs, 2016 |
| US healthcare-associated cases, 2015 | 85 definite and 468 possible, in 72 facilities | CDC Vital Signs, 2017 |
| Case fatality, definite healthcare-associated cases | 25 percent | CDC Vital Signs, 2017 |
The line I put in front of every hospital and care home manager is the fifth one. In 23 of the 27 outbreaks, investigators found process failures, human error, equipment failures or unmanaged external changes, the things a working water management programme is designed to catch.
Where are the Legionella risks in a hospital, clinic or care home?
| System | Why it matters in healthcare | Control |
|---|---|---|
| Hot water storage and loops | Patients shower and wash in it | Store at 60 °C or above, outlets at least 55 °C within one minute, every return at least 55 °C |
| Thermostatic mixing valves | Blended water downstream can let Legionella multiply | As close to the outlet as possible, fail-safe checked, strainers cleaned annually or per risk assessment |
| Assisted bathing showers and hoses | Spray in the breathing zone of frail people | Hung up to drain, cleaned, descaled and disinfected quarterly |
| Nebulisers | Aerosol delivered straight into the lungs | Sterile water only to fill, sterile water to rinse |
| Cold water storage tanks | Warm, stagnant water feeding wards | No more than 12 hours’ use, inspected annually |
| Little-used outlets | Stagnant water at an empty bedside | Flushed weekly, or removed |
| Powered dental equipment | Water lines that spray into the mouth | Drained, cleaned, flushed and disinfected twice daily (HSG274 Part 3) |
The CDC’s water management toolkit lists healthcare facilities with overnight stays and senior housing among the buildings that need a water management programme, and decorative fountains as devices that need one in any building.
The care workers who bath residents need the routine too
Legionella Awareness Training teaches care, cleaning and maintenance staff the temperature numbers, how to flush and clean showers safely, what to report and to whom, with a 90-bed frail care centre as one of the cases. Four hours on a phone, R799 a person.
Should a care home turn the geysers down to stop scalding?
No. Every frail care manager fears a resident scalded in the bath, and fairly so. At Sinethemba Care Centre, the frail care case in our courses (a training scenario built from real audit patterns), the six 300 litre geysers were turned down to 50 °C after a resident was scalded in 2022, with no TMVs fitted. The scald risk went down and the Legionella risk went up, in a building full of the people least able to survive it. The National Environmental Health Norms and Standards for Premises and Acceptable Monitoring Standards for Environmental Health Practitioners (GN 7779, 2026) also require health establishments to keep hot water above 50 °C and cold water below 20 °C (8.2.9), so the 50 °C setting does not meet the norm.
ASC’s rule: never solve a scald risk by turning the storage temperature down. The order of work matters:
- Fit type 3 thermostatic mixing valves as close as possible to the outlets where residents wash, and test that they fail safe if the cold supply stops.
- Only then raise storage to 60 °C or above. Raising it first puts very hot water at the outlets of the people the scald fix was meant to protect.
- Take hot sentinel readings at outlets without a TMV, not at a resident’s basin or shower, which should run at a mixed, safe temperature.
- Clean, descale and disinfect TMV strainers and filters annually or as the risk assessment says.
The temperature science is in our hot water temperature guide.
Free tool: walk your care home or clinic
The free Legionella Water Walk has a healthcare setting that applies the 55 °C outlet and return limits and the 12 hour storage rule. It ranks what it finds and exports the list.
Try the free Water Walk, then learn to act on what it finds in Legionella Awareness Training (R799).
What else does a frail care walk-through find?
- Hand-held showers left lying in the shower trays. Water stands in the hose and the head sits in the tray. Hang them up to drain and put them on the quarterly clean, descale and disinfect. Our flushing and showerhead guide has the procedure.
- Nebuliser parts rinsed under the tap. CDC guidance on preventing healthcare-associated pneumonia: clean, disinfect, rinse with sterile water and dry nebuliser parts between treatments, and fill reservoirs only with sterile water. Never rinse parts in tap water and put them straight back into use.
- A borehole and three plastic storage tanks, two with cracked lids. In healthcare, stored cold water should not normally exceed 12 hours’ use, and ASC treats a care centre as healthcare. See our guide to water storage tanks.
There is no cooling tower or evaporative condenser on site, so the assessment concentrates on water, showers, tanks and nebulisers.
What happens when a resident tests positive?
In the Intermediate course, Sinethemba’s case takes a turn. A 78-year-old resident in Wing C is admitted to hospital with pneumonia and tests positive on a Legionella urinary antigen test. Ten weeks earlier, a resident from the same wing was treated for pneumonia, cause not identified.
- Notification is by the doctor or laboratory that diagnoses it, within 7 days. Legionellosis is a Category 2 notifiable medical condition.
- A cluster, under NICD guidance, is two or more cases linked to one location within 12 months. It triggers a full environmental assessment, ideally starting within 24 hours. Whether the earlier pneumonia counts is for the investigating environmental health practitioner to judge.
- The urine test detects L. pneumophila serogroup 1, so a negative result does not rule out other serogroups or species.
- Do not drain, flush, dose or disinfect the wing’s water on your own. Take outlets out of use to protect residents, and agree the next steps with the EHP so samples are taken before the evidence is destroyed.
For remediation, the Australian health and aged care guideline (enHealth, 2015) gives thermal disinfection at 70 °C or above for at least 5 minutes at each outlet (60 °C or above for at least 10 minutes where 70 °C cannot be reached), or hyperchlorination, holding at least 2 mg/L free residual chlorine through the system while each outlet is flushed for at least 5 minutes. Either method is contractor work under a written method statement, and in a frail care wing the order is fixed. Fit and test the TMVs first. Then disinfect with every outlet in the area locked off and residents kept away until the water is back to its normal temperature, because water at 70 °C scalds in moments. Then hold storage at 60 °C or above. Resample 3 to 7 days later. Heat only holds for weeks unless the cause is fixed. Our Legionella testing guide covers sampling and results.
Which limits are tighter in healthcare?
| Control | Most buildings | Healthcare (and frail care, ASC position) |
|---|---|---|
| Hot water at outlets within one minute | At least 50 °C | At least 55 °C (HSG274 Part 2) |
| Hot water returns | At least 50 °C | At least 55 °C (HSG274 Part 2, enHealth) |
| Stored cold water | No more than one day’s use | No more than 12 hours’ use |
| Cooling tower restart | Clean and disinfect after a month or more | After more than 5 days |
| Routine hot and cold sampling | Not usually needed where temperatures are consistently met | Indicated, because the population is more susceptible |
| Legionella result that triggers action | More than 100 cfu/L review, more than 1 000 cfu/L act now (HSE) | Any detection (enHealth) |
The older South African code (WRC TT 174/02, 2003) treats hospitals and frail care as low risk below 1 000 Legionella per litre and calls for urgent action above it. ASC teaches the stricter current rule: in healthcare, any detection is a trigger.
South African law sets a floor too: GN 7779 (8.2.9) requires health establishments to keep hot water above 50 °C and cold water below 20 °C to prevent organisms such as Legionella spp. HSG274’s 55 °C outlet figure is stricter, and ASC teaches it.
What changes in a healthcare water management plan?
The structure is the same as for any building, and our water management plan template walks through it. What changes is the team (nursing and infection control alongside maintenance) and the clinical items: nebulisers, assisted bathing, TMVs and dental lines. Section 9 of the OHS Act covers patients and residents. The HBA Regulations keep Legionella spp. at Risk Group 2 and require the risk assessment to deal with pregnant, immunocompromised and vulnerable employees. Who carries the duty is covered in who is responsible for Legionella.
What you walk away with from the Responsible Person course
- An asset register and schematic method for every water system in the building
- The ASC risk rating scale, where frail care residents rate as the most severe consequence
- A monitoring schedule and corrective action matrix
- A results reader that applies the healthcare any-detection rule
- The plan builder, which exports your own plan as an xlsx workbook
- A dated certificate on passing. HPCSA CPD accredited
Build a plan you can show an investigating EHP
From TMVs and nebulisers to the any-detection rule and the first hours after a positive test. Online, self-paced, R2 950.
Frequently asked questions
Why is Legionella more dangerous in hospitals?
Because hospitals and care homes are full of the people most likely to fall seriously ill: older people, smokers, and people with lung disease, diabetes, cancer or weak immune systems. The CDC says about 1 in 4 people who catch Legionnaires’ disease during a healthcare stay die, against about 1 in 10 overall.
What temperature should hospital hot water be?
Stored at 60 °C or above, reaching outlets at 55 °C or more within one minute, with every circulation return at least 55 °C (HSE HSG274 Part 2). South African law (GN 7779, 8.2.9) sets a floor of above 50 °C for health establishments. Where patients could be scalded, fit and test thermostatic mixing valves at their outlets instead of turning the storage down.
Does a frail care centre need a Legionella water management plan?
Yes. Residents are covered by section 9 of the OHS Act, and the HBA Regulations, 2022 require a documented risk assessment by a competent person. The CDC lists healthcare facilities with overnight stays and senior housing among buildings that need a water management programme.
What Legionella result needs action in a hospital or care home?
Any detection. Australia’s enHealth guideline for health and aged care says any Legionella detection triggers corrective action and immediate control of exposure of vulnerable people, and ASC teaches that rule. The older WRC 2003 code treated anything below 1 000 per litre as low risk, which is too loose for frail people.
How should nebulisers be rinsed to prevent Legionella?
With sterile water. CDC guidance says clean, disinfect, rinse with sterile water and dry nebuliser parts between treatments, and fill reservoirs only with sterile water. If sterile rinsing is not feasible, use filtered or tap water followed by an isopropyl alcohol rinse and forced-air drying.
Should we turn the geysers down to stop residents being scalded?
No. Turning storage down puts the water in the range where Legionella grows. Fit type 3 thermostatic mixing valves close to residents’ outlets, test them, then raise storage to 60 °C or above. Raising the temperature before the valves are in puts very hot water at residents’ outlets.
What should a care home do if a resident has Legionnaires’ disease?
Take the suspected outlets out of use, but do not drain, flush, dose or disinfect on your own. The diagnosing doctor or laboratory notifies within 7 days. Agree next steps with the investigating environmental health practitioner, so samples are taken before evidence is destroyed.
Train your care staff before the next scald fix
Ten hours for the manager who carries the duty, with the healthcare limits, the incident response and a full water management plan. Four hours for the care, cleaning and maintenance staff who run the routine every week.
Start the Responsible Person course (R2 950) →Awareness Training for your team (R799)Self-paced, works on a phone. HPCSA CPD accredited. Certificate on passing.
Sources and further reading
- CDC: about Legionnaires’ disease
- CDC Vital Signs: Legionnaires’ disease outbreaks, 2000 to 2014
- CDC Vital Signs: healthcare-associated Legionnaires’ disease, 2015
- CDC and HICPAC: preventing healthcare-associated pneumonia (2003)
- HSE HSG274 Part 2: hot and cold water systems
- enHealth (2015): Legionella control in health and aged care
- Wolter et al. (2016): Legionella in severe respiratory illness, South Africa
- NICD recommendations for Legionnaires’ disease
- WRC TT 174/02 (2003): guidelines for Legionella levels in water
- National Environmental Health Norms and Standards (GN 7779, 2026)