Veterinary practices, kennels, catteries and animal-hydrotherapy centres do carry a Legionella duty - but the law you are meeting protects the people on site, not the animals. Staff, clients in the waiting room, and a hydrotherapist leaning over a warm pool are the ones who can breathe in a contaminated droplet. Your dogs and cats are not the reason for the assessment.

That distinction is the most useful thing to get straight, because it tells you where to spend effort. Legionnaires’ disease is caught by inhaling a fine spray of water small enough to reach the lungs [1]. So the question for an animal-care site is narrow: which parts of your plumbing and equipment turn warm, possibly stagnant water into a breathable mist near a human? Answer that and the rest of the programme falls into place.

Your duty is to people, not patients

Anyone who controls premises has to assess and manage the risk of exposing people to Legionella from a water system; the Approved Code of Practice L8 sets that expectation [2], and HSG274 supplies the technical detail [3]. None of it concerns animal welfare - that sits under the separate veterinary and licensing rules you already meet.

So your “people at risk” are employees, contractors and members of the public who enter the building or stand beside the equipment. Some clients are older or have weaker chests, which is exactly the group more vulnerable to a respiratory infection - another reason the public-facing aerosol generators deserve attention. None of this requires you to think about whether the water is safe for the animals; it requires you to think about who is standing in the spray.

Where the risk actually sits on an animal-care site

A vet or boarding site has the ordinary hot and cold water of any small commercial building, plus a handful of aerosol generators that an office never sees. The ordinary plumbing follows ordinary rules. The unusual kit is what makes this topic its own subject.

Wash-down hoses and spray guns. Kennel and cattery runs, prep rooms, theatres and isolation wards get hosed down daily. A spray gun or pressure lance throws a fine mist straight into the breathing zone of whoever is holding it. If the hose has sat full of warm water since the last shift, that mist carries whatever grew inside the bore. This washdown hose Legionella route is the one most animal sites overlook because the hose looks clean. The water inside it is the problem, not the outside.

Hydrobaths and grooming sprays. A grooming hydrobath recirculates warmed water, and the hand-spray aerosolises it at arm’s length from the groomer’s face. The spray head itself scales up and harbours biofilm in exactly the way a salon backwash fitting does - the same logic covered in Legionella in hairdressers, salons and barbershops: backwash basins and sprays. Treat the grooming hydrobath risk as a cleaning-and-descaling task with a written schedule, not an occasional wipe.

Animal hydrotherapy pools. A warmed, recirculated pool held in the high-20s to low-30s Celsius sits inside the bacterial growth range, and the jets, ramps and a dog shaking itself off all generate aerosol. The exposed person is the human in or beside the water. The control thinking is close to the human case set out in Hydrotherapy pools and Legionella: warm water, vulnerable users, higher stakes: keep turnover and disinfection logged, and treat the splash zone as a respiratory risk to staff. That is the heart of animal hydrotherapy pool Legionella control.

Showers, taps and rarely-used outlets. Staff showers, an outside tap on a kennel block, a spare consult room, a seasonal cattery wing used a few weeks a year - little-used outlets let water stagnate and warm towards room temperature. Scale, sediment and dead legs behind decommissioned equipment do the rest.

A walk-round checklist for a vet, kennel or cattery site

Use this on a clipboard or your logbook app, area by area, and record a date and an initial against each line. It is built for kennels cattery water hygiene and clinic plumbing together, so skip the lines that do not apply to your premises.

Hot and cold water basics

  • Confirm you hold a current site Legionella risk assessment that covers the whole building, and review it whenever you move equipment or change the layout.
  • Record hot water leaving storage and at the furthest (sentinel) taps, and cold water at representative outlets. Stored hot around 60C, roughly 50C at the tap and cold below 20C are the usual targets, but your risk assessment confirms the figures for your site [4].
  • Identify and remove or shorten dead legs left behind by removed sinks, old kennel banks or relocated kit.

Aerosol-generating equipment

  • List every wash-down hose and spray gun. Drain or flush hoses after use rather than leaving them charged with warm water; do not store a hose coiled and full.
  • Strip, clean and descale hydrobath spray heads, grooming sprays and shower roses on a recorded schedule.
  • For an animal hydrotherapy pool, log turnover, disinfection and water-quality checks, and brief staff that the splash zone is an aerosol they breathe.

Little-used and seasonal outlets

  • Map every outlet used less than weekly - isolation runs, spare consult rooms, seasonal cattery wings, the staff shower nobody uses in summer.
  • Flush those outlets on a routine you can evidence, running each long enough to draw through fresh mains water.

People and records

  • Name a responsible person who owns the programme, and keep the logbook current.
  • Brief groomers, kennel staff and hydrotherapists on why the descaling and flushing matters - they are the ones standing in the spray.

Keeping the controls proportionate

The trap on an animal site is the opposite of neglect: spending money testing the pool water for the dogs’ sake while the daily wash-down hose - the genuine human exposure - is never on the schedule. Match effort to where a person breathes the aerosol.

A single-vet practice with mains-fed taps, a couple of basins and no showers may have a short, simple assessment and a light monitoring routine; some of that thinking is set out in our piece on low-risk premises. A boarding kennels with hydrobaths, daily pressure-washing and a hydrotherapy pool is a different animal, closer in risk profile to the spray-heavy plant covered in Legionella prevention in industrial facilities. The clinical side of a busy veterinary practice - dental units, suction lines and instrument water - mirrors the small-bore, aerosol-prone fittings discussed in Legionella control in dental clinics and surgeries, and is worth a separate line in your assessment.

This article is general guidance, not a substitute for a competent, site-specific risk assessment, and it is not legal, veterinary or design advice. The figures and frequencies that actually apply to your premises come from your own assessment, carried out by someone competent to do it; treat the lists here as prompts for that work rather than a finished scheme.

Frequently asked questions

Do I need a Legionella risk assessment if my practice only has hand basins and no showers?

You still need to assess the risk, but the assessment may be brief and conclude that controls are simple. The duty is to identify and manage the risk, not to install testing for its own sake. A site with hydrobaths, wash-down hoses or a hydrotherapy pool has far more to assess than one with cold-fed basins alone.

Is the animal hydrotherapy pool a danger to the dogs or to my staff?

For Legionella purposes it is your staff and clients who matter - the hydrotherapist standing in the splash zone, not the dog swimming. Animal health is governed by other rules. Log the pool’s turnover and disinfection, and treat the aerosol as a respiratory risk to people.

The wash-down hose looks clean, so why is it a risk?

Because the risk is the warm water sitting inside the bore between uses, not the outside of the hose. When you next pull the trigger, that water leaves as a fine mist near your face. Draining hoses after the shift and not storing them charged is the cheapest control you can put in place.

Your next step this week

Walk the premises once with the checklist above and mark every point where warm water becomes a spray near a person - the hydrobath, the wash-down lance, the pool, the staff shower. Hand that list to whoever holds your water-safety records and ask for those specific outlets to be added to the next risk-assessment review. Start with the hoses; they are the item most likely to be missing from your current scheme.

Sources

[1] HSE, “Systems most likely to create legionella risk”. https://www.hse.gov.uk/legionnaires/risk-systems.htm [2] 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 [3] HSE, “Legionnaires’ disease: Technical guidance (HSG274)”. https://www.hse.gov.uk/pubns/books/hsg274.htm [4] HSE, “Hot and cold water systems”. https://www.hse.gov.uk/legionnaires/hot-and-cold.htm