Legionella can develop in water systems when conditions are right.

Here’s what it is, who’s most at risk, and the simple steps that help reduce the chance of exposure.

Legionella is a type of bacteria that can grow in water systems, particularly when water is stored or sits still for long periods. It becomes a concern when tiny droplets of contaminated water are breathed in; commonly through aerosols created by showers, taps, hoses, pressure washers, or some commercial systems. While serious illness is uncommon, it can be severe, so prevention is always the best approach.

The good news is that the conditions Legionella prefers are well understood. Risk increases when water is stagnant, when temperatures sit in the “warm but not hot” range, and when there is scale, sludge, rust, or biofilm that gives bacteria a place to grow. These issues can crop up in a range of settings; from homes with little-used pipework to larger premises with water tanks, long pipe runs, dead legs, or seasonal use.

Who’s most at risk

Certain people are more vulnerable to Legionnaires’ disease, including older adults, smokers, and those with weaker immune systems or underlying health conditions. That doesn’t mean others are risk free; it simply means prevention and good water hygiene matters for everyone.

Practical ways to reduce risk

Here are some sensible steps that can help lower risk in domestic and light commercial settings:

• Run little-used taps and showers to flush the system, especially after time away.

• Keep hot water hot and cold water cold; hot water should reach a temperature that discourages bacterial growth, and cold water should be stored and delivered as cold as possible.

• Clean and descale shower heads and hoses regularly, as scale and biofilm can build up over time.

• Avoid long periods of stagnation in unused areas of a property, outbuildings, or spare rooms.

• For businesses and landlords: consider a structured approach; basic monitoring, record keeping, and periodic checks depending on the type of premises and system.

When to get professional support

If you manage a property with water storage tanks, complex pipework, a history of temperature problems, or buildings that are empty for stretches of time, it may be worth arranging a professional review. A simple inspection can highlight common issues like dead legs, poorly insulated pipework, and areas of low circulation.

If you’d like help understanding what’s sensible for your property type, get in touch and we can point you in the right direction.