The Legionella risk in a food business is almost never the cooking. It hides in the water assets that get wiped down for food safety but never assessed for water hygiene: the ice machine, the pre-rinse spray arm over the pot sink, the glass washer, the tap in the function room nobody has run since the last wedding.

Those things make a fine spray, hold warm standing water, or both. The fryer and the hob do not.

Legionella reaches people when contaminated water is broken into a breathable aerosol and drawn into the lungs [2]. In a restaurant or pub that means the spray off a tap, the mist from a dishwasher door opening, the haze from a hose washing down a yard — not water that is boiled, and not food that is cooked. So the duty here is the ordinary one every employer carries: identify the water systems that could create risk, assess them, and control them through a written scheme [1]. The snag is that hospitality kitchens already run tight cleaning regimes for food, and it is easy to assume the Legionella side rides along on the same rota. It usually does not.

Where the real risks sit, and why food hygiene misses them

Food hygiene asks whether a surface is clean and whether food is safe to serve. Legionella control asks a different question: does this part of the water system let the bacteria grow, and does it then make a breathable spray. A spotless stainless worktop can sit a foot from a furred-up spray-tap aerator. The two routines overlap — both reward cleaning, descaling and good records — but they are not the same audit, and an outlet can pass one while failing the other.

The assets worth your attention share three traits: they hold water at lukewarm temperatures, they are used only now and then, or they generate spray. Plenty tick two of the three.

The field checklist

Walk the building with this, grouped the way the site is actually laid out. Make every line something you can date and sign.

Front-of-house and WCs

  • Run every customer and staff WC basin, especially in cloakrooms that only open at weekends or for functions, so the outlet is not left stagnant [3].
  • Check and service the thermostatic mixing valves (TMVs) on blended basins — blended water sits in the 30–45°C growth band, and a neglected TMV is a small warm reservoir feeding a tap people use close to their face [4].
  • Flush taps in the disabled WC and any cloakroom that is rarely the busy one.
  • Descale and clean tap aerators and any spray fittings that produce a mist.

Kitchen and wash-up

  • Identify the pre-rinse spray arm at the pot wash — it atomises water every time it is squeezed, and it is the classic forgotten aerosol source in a kitchen.
  • Put glass washers and dishwashers on a cleaning and descaling schedule, and treat the burst of warm vapour when the door opens as the exposure point, not just steam.
  • Flush the hand-wash and prep-sink taps on days the kitchen is closed.
  • Service any water softener, filter housing or boiling-water tap on the manufacturer’s schedule rather than “when the water tastes off”.

Cellar and outside

  • For pub cellars, log the cellar cooling unit and any remote beer cooler or ice-bank with a recirculated water bath, and keep condensate trays and drains clean.
  • Service outside and hose-down taps, and never leave a hose attached holding warm, sun-heated water that sprays out on first use.
  • Flush taps in seasonal spaces — beer gardens, marquees, upstairs function rooms — before the season opens, not on the morning of the first booking.

Drinks and ice

  • Put every ice machine on the water risk assessment and the cleaning log, not just the catering rota.
  • Clean and sanitise post-mix and drinks dispensers, water coolers, and the supply lines and carbonators behind them on a set schedule.
  • Run drinking-water and bottle-refill taps that staff or customers only use occasionally.

Recording it without conflating it with food safety

The pragmatic move is to fold these into the rotas you already keep, but tag them as water-hygiene tasks with their own evidence. A glass-washer descale can sit on the same weekly sheet as the food-safety clean, provided it is a separate, dated line that a water-hygiene check would accept on its own terms. Keep the two stories distinct: an environmental health officer and a Legionella assessor are asking different questions, and one tidy “we clean everything” note answers neither well.

Two cross-references save repeating detail here. Ice machines have their own quiet failure mode — warm standing water and biofilm in a unit nobody strips down — set out in Ice machines and Legionella. The drinks side, from water coolers to post-mix, is covered in Are water coolers and bottle-filling stations a Legionella risk?.

Pubs: the seasonal and closed-day trap

Pubs add a pattern most restaurants dodge: long quiet spells. A function room booked solid for a Christmas run and then silent until spring. A garden bar that is dry all winter. A let above the trade that sits empty between tenancies. Each is a set of outlets going stagnant in the growth band, and the answer is a flushing regime that keeps water moving through them weekly, plus a deliberate recommissioning flush before a space reopens. Closed Mondays count too: a regular two-day weekly closure is usually short enough not to matter much, but a fortnight’s refit shutdown is not, and that distinction belongs in your assessment [3]. The wider hospitality picture — guest rooms, spas, patchy occupancy — runs alongside this in Legionella risks in hotels and hospitality.

The items people skip

Three get missed almost every time. The pre-rinse spray arm, because it reads as a tap rather than a sprayer. The outside hose tap, because it is “only for cleaning”. And the rarely-used outlet — the disabled WC, the cellar sink, the seasonal bar — because low use feels like low risk when it is the opposite. Stagnation, not heavy use, is what grows the bacteria. Several of these recur on the wider list of common Legionella control mistakes.

A caveat that applies to your site

A single small café with a domestic-style boiler and three taps is not a large gastropub with a cellar, a function suite and an ice machine on every floor, and the two will not need the same scheme. What goes on the assessment, how often each outlet is flushed or descaled, and whether any of it warrants sampling are decisions for a competent person working from a risk assessment of your actual premises [1][5]. This is general guidance on where to look, not legal advice or a control scheme for your building.

Your next step this week

Take the checklist above and walk your premises once, marking every water outlet you find — including the ones that only run seasonally. For each, answer three things: is it on the risk assessment, who cleans or flushes it, and when did that last happen with a record to prove it. Every blank is a task, not a verdict. Then give those recurring flushes and descales a dated home rather than a memory, so the rarely-used tap and the quarterly ice-machine strip-down stay visible instead of quietly lapsing between busy services.

Common questions

Does a restaurant need a Legionella risk assessment?

Yes. Any employer or person in control of premises with a water system has to assess and manage the Legionella risk, and a commercial kitchen with taps, a dishwasher, an ice machine and WCs plainly qualifies [1]. The assessment can be proportionate to a small, simple system, but having no showers does not remove the duty.

Is the kitchen tap the biggest risk?

Usually not. A tap in constant use, fed with properly cold or properly hot water, is lower risk than an outlet that sits stagnant or one that throws a fine spray. The pre-rinse spray arm, the glass washer and the long-idle function-room tap deserve more attention than the busy hot tap on the main run [3].

We close two days a week — does that matter?

A regular two-day closure is usually short enough that normal use on reopening clears it, though your assessment should confirm that for your system. The longer gaps are the issue: a seasonal room, a winter beer garden or a refurbishment shutdown can leave outlets stagnant long enough to need a planned flush before they are used again [3].

Sources

[1] HSE, “Legionnaires’ disease - what you must do”. https://www.hse.gov.uk/legionnaires/what-you-must-do/index.htm [2] CDC, “How Legionella Spreads”. https://www.cdc.gov/legionella/causes/index.html [3] HSE, “Systems most likely to create legionella risk”. https://www.hse.gov.uk/legionnaires/risk-systems.htm [4] HSE, “Hot and cold water systems”. https://www.hse.gov.uk/legionnaires/hot-and-cold.htm [5] HSE, “Legionnaires’ disease. The control of legionella bacteria in water systems - Approved Code of Practice and guidance (L8)”. https://www.hse.gov.uk/pubns/books/l8.htm