Legionella risk assessment in Cardiff

Updated 16 August 2026

Cardiff's legionella risk assessment work is governed by the same HSWA 1974 and ACOP L8 framework that applies across Great Britain, with enforcement through Public Health Wales and the relevant local authority environmental health team. The city's NHS estate at University Hospital of Wales and the large student accommodation market around Cardiff University drive most of the demand.

Local water supply

The mains water supplier for Cardiff is Dŵr Cymru Welsh Water (Dŵr Cymru Welsh Water website). The mains supply is treated and controlled by the supplier, so your legionella duties begin where the water enters your premises. Anything downstream of the boundary stop tap (storage tanks, calorifiers, pipework, outlets) is your responsibility.

Water in the Cardiff area is classed as Soft on the Drinking Water Inspectorate hardness scale (around 45 mg/l as CaCO₃), according to MyTapWater water quality data (single source - unverified). Harder water lays down scale inside calorifiers, cylinders, and mixing valves, and scale gives legionella a foothold while blunting temperature control, so in hard-water areas descaling and inspection belong in the written scheme of control. Check your supplier's postcode water-quality checker for the figure for your exact supply zone.

Legionnaires' disease in Wales

The most recent regional surveillance figures recorded 43 confirmed cases of legionellosis in Wales in 2023, a rate of 1.4 per 100,000 residents.

These are the confirmed figures UKHSA states explicitly; a full region-by-region table is not published, and surveillance counts only laboratory-confirmed, reported cases, so they are a floor rather than the true total. The national picture, with the trend since 2017, is on the Legionella Data Index. The regional figure changes nothing about your own duties: whatever the count, a non-domestic water system in Cardiff still needs a risk assessment, a control scheme, and the records to show the scheme is being followed.

Typical cost in Cardiff

Legionella risk assessment costs in Cardiff depend more on the water system than on the location. A rough guide:

• Small premises, mains-fed only, no storage: £150 to £250
• Typical office or shop with a hot water cylinder: £200 to £400
• Care home, hotel, or school with stored hot and cold water: £400 to £800
• Premises with a cooling tower or evaporative condenser: from £800, often much higher

Cooling towers drive the cost up because they are notifiable to the local authority under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992, and they need quarterly sampling and extensive cleaning. Get a tailored estimate with our cost calculator.

Legionella enforcement in Wales

Prosecutions for legionella failings are usually brought under the Health and Safety at Work etc. Act 1974, whether by the HSE, a local authority, or (in Scotland) the Crown Office and Procurator Fiscal Service. No case in our tracker is recorded in Cardiff itself; the cases below are the most recent recorded elsewhere in Wales, shown as regional context rather than local history. They are drawn from our legionella enforcement tracker, which records each one against its primary source:

Coilcolor Limited, 2015 (Manufacturing) — fined £75k. A Newport steel-coating firm ran two cooling towers from 2009 with no risk assessment, no written scheme, no water-treatment programme and missing drift eliminators, exposing staff and the public to aerosol. The HSE served prohibition notices stopping the towers being used.

DEBA UK Ltd, 2009 (Water treatment) — fined £24k. A risk-assessment contractor (not the care-home operator) carried out inadequate legionella risk assessments in 2007 that wrongly rated two Craegmoor Healthcare nursing homes in Wales as low risk, where controls were in fact inadequate. No outbreak or death resulted. Pleaded guilty to three charges under HSWA s3(1) and was fined £24,000 plus £17,276 costs at Abertillery Magistrates' Court in August 2009. Notable as a prosecution of the assessor rather than the duty-holder.

The failings behind these cases are consistent: no suitable risk assessment, no written scheme of control, monitoring not carried out, or records that could not show the controls happened. The full dataset is on the enforcement tracker, and legionella fines and prosecutions explains how the courts approach sentencing.

Find a legionella risk assessor in Cardiff

We are building a directory of qualified water hygiene assessors in Cardiff and across the UK. In the meantime, look for assessors who:

• Work for a company registered with the Legionella Control Association (the LCA is the main UK trade body for water hygiene)
• Hold a City & Guilds or equivalent qualification in legionella risk assessment
• Can provide references from similar premises in the Cardiff area
• Will quote against a clear scope (number of outlets, inclusion of hot and cold surveys, whether sampling is included)

Legionella testing labs covering Cardiff

Routine temperature monitoring is done on site, but where your risk assessment or written scheme calls for water sampling, the samples go to a laboratory for culture. None of the UKAS-accredited laboratories in our directory is based in Cardiff itself, so the nearest UKAS-accredited labs are listed below — all accept postal samples, and posted sampling is how most premises use them:

• Feedwater Laboratories (UKAS no. 2234), turnaround ~10 days, from £82.68 per sample
• Eurofins Water Hygiene Testing UK Limited (UKAS no. 9658)
• ALS Environmental (ALS Laboratories (UK) Limited) (UKAS no. 1314)

Methods, turnaround times and published prices for the full directory are compared on the legionella testing labs page. Sampling is not a substitute for day-to-day control: a clear result records what was found at that outlet on that day, it never certifies a system as safe, and it sits alongside the routine checks in your written scheme of control, not instead of them.

Building types in Cardiff

Different building types have specific legionella considerations. Browse the guides most relevant to Cardiff premises:

• Landlords and rental properties
• Offices
• Care homes
• Hotels
• Schools
• Dental practices
• All building types