A Legionella risk assessment is a documented survey of a building's hot and cold water systems and any aerosol-generating equipment to identify where Legionella bacteria could grow and what controls are needed to prevent it. It is a legal requirement under the Health and Safety at Work Act 1974, COSHH Regulation 6, and ACoP L8 for any employer or person in control of premises with a water system — including standard offices. The assessment must be in writing for any business with five or more employees and reviewed at least every two years, more frequently for higher-risk systems.
Legionella risk assessment is a legal duty for any employer or person in control of premises with a water system — and that duty applies to standard offices, not just complex industrial sites. RiskSorted assessors are members of the Legionella Control Association (LCA) and produce assessments to ACoP L8, HSG274 Parts 1–3, and BS 8580-1:2019. All assessors carry minimum £2m Professional Indemnity insurance and are matched to your specific water system type — standard hot and cold water systems for office and small commercial, cooling tower and evaporative system specialists for industrial and large hospitality, healthcare-experienced assessors for care environments. Results are stored in your account with automatic review reminders.
Survey of all hot and cold water systems (cold water storage tanks, calorifiers, plate heat exchangers, distribution pipework), all outlets including infrequently-used ones (dead legs, seldom-used taps, emergency eyewash stations, safety showers), all aerosol-generating systems (cooling towers, evaporative condensers, spa pools, decorative water features), and any thermostatic mixing valves (TMVs). Identification of vulnerable occupants. Temperature monitoring point recommendations. Site-specific risk score per outlet category. Recommended written scheme of control under ACoP L8.
Full ACoP L8 / HSG274 risk assessment report, schematic of water system with asset register, prioritised control measures with timescales, recommended monitoring schedule (temperature checks, flushing regime, sampling frequency where indicated), site-specific written scheme of control, review date, and certificate signed by your LCA assessor. All records retained for the ACoP L8 minimum five-year period in your RiskSorted account, with audit-ready export. Where vulnerable occupants are present (healthcare, care, supported housing), the report includes an enhanced control framework.
| Assessor qualification | Legionella Control Association (LCA) member; City & Guilds 6041/6042 or equivalent |
| Insurance requirement | Minimum £2m Professional Indemnity |
| Report standard | ACoP L8 (4th edition); HSG274 Parts 1–3; BS 8580-1:2019 |
| Record retention (statutory minimum) | 5 years from ACoP L8 |
| Average duration | 2 to 4 hours for typical commercial premises; full day for healthcare or cooling-tower sites |
| Certificate format | Branded PDF assessment with full water system schematic, stored in your account |
| Review reminder | 60 and 30 days before review date — automatic |
UK Legionella risk management sits within a layered framework of primary legislation, regulations, and an Approved Code of Practice that has special legal status. The legal foundation is the Health and Safety at Work etc. Act 1974, which places a general duty on every employer to ensure, so far as is reasonably practicable, the health and safety of employees and others affected by the work. Section 3(1) extends this duty explicitly to non-employees — the public, contractors, visitors — who could be exposed to Legionella through the workplace's water systems.
The Control of Substances Hazardous to Health Regulations 2002 (COSHH) apply specifically to Legionella as a biological agent under Regulation 6, requiring a suitable and sufficient assessment of the risks to health created by work liable to expose persons to a substance hazardous to health. The Management of Health and Safety at Work Regulations 1999 (MHSWR) Regulation 3 adds the broader workplace risk assessment duty under which Legionella sits as one identified risk. Together, these regulations establish that the duty to assess Legionella risk applies to every UK workplace with a water system, regardless of size — including standard offices on mains water supplies.
The Approved Code of Practice L8 — Legionnaires' disease: The control of Legionella bacteria in water systems (4th edition) is the technical reference that interprets these legal duties. ACoP L8 has special legal status: if you are prosecuted for breach of health and safety law and it is proved that you did not follow the relevant provisions of the Code, you must show that you complied with the law in some other way, or a court will find you at fault. In practice, ACoP L8 compliance is the recognised defensible standard. Four areas in the 4th edition have ACoP status (legal weight): risk assessment procedures, the role of the responsible person, written schemes of control, and review processes.
HSG274 — Legionnaires' disease: Technical Guidance provides the operational detail that supports ACoP L8. It is split into three parts: Part 1 covers cooling towers and evaporative condensers; Part 2 covers hot and cold water systems (the most common scope for offices, hospitality, and standard commercial); Part 3 covers other risk systems including spa pools and decorative water features. HSG274 Part 2 also defines the tiered Legionella action framework — counts between 100 and 1,000 CFU/L trigger a review of the risk assessment, control measures and water management programme; counts exceeding 1,000 CFU/L require immediate corrective action.
BS 8580-1:2019 — Risk assessments for Legionella control. Code of practice is the British Standard that sets out the methodology for Legionella risk assessments specifically. Where ACoP L8 establishes the legal duty and HSG274 covers technical control, BS 8580-1:2019 standardises how the assessment itself is conducted — the structure of the survey, the asset register, the risk-scoring approach, and the format of the output. RiskSorted assessors work to all four documents.
An ACoP L8 risk assessment doesn't just identify hazards — it drives a complete written scheme of control. The recommended controls fall into a consistent structure across most premises:
The assessment identifies which of these controls are required for your specific premises, calibrated to the risk profile of your water system and occupants. A small office on mains water with no stored hot water and no aerosol-generating equipment will receive a substantially lighter control scheme than a hotel with cooling towers and a spa pool — but both need an assessment, and both will receive a documented written scheme of control proportionate to the actual risk.
Legionella risk assessment pricing varies more than most compliance services because the work scales directly with water system complexity, not just floor area. Market rates currently sit roughly as follows.
Simple low-risk premises (small office, retail, single-tenant commercial on mains water): £250 to £400. Site time 2 to 3 hours. Limited stored water, no cooling towers, no aerosol-generating equipment. Standard ACoP L8 risk assessment with light-touch written scheme of control.
Medium-complexity premises (mid-size offices with stored hot water, smaller hotels and hospitality, gyms with shower facilities, schools, GP surgeries): £400 to £700. Site time 3 to 5 hours. Hot water storage, multiple shower outlets, infrequently-used outlets requiring flushing regime specification. Standard HSG274 Part 2 scope with full schedule.
Higher-complexity premises (hotels with substantial pipework, healthcare, care homes, supported housing, large multi-tenant commercial): £700 to £1,500. Site time half-day to full day. Vulnerable occupants drive enhanced control requirements. PCFRA-equivalent vulnerability assessment integrated into the report.
Cooling-tower or industrial water-system premises: £1,500 to £4,000+. HSG274 Part 1 scope adds substantial technical specialism — cooling tower water treatment, biocide regimes, drift eliminators, blowdown programmes. Site time often a full day with follow-up assessment of treatment chemistry. Specialist water hygiene consultancy territory.
RiskSorted's pricing is shown in full at the point of booking based on your premises type, water system characteristics, and occupant profile. There are no hidden extras for the schematic, the written scheme of control, or storage of records in your account. Where ongoing monitoring is recommended (sampling, temperature monitoring, flushing supervision), that's quoted separately as a service contract rather than padded into the assessment fee.
Bundle savings. Most office and small commercial customers who book a Legionella risk assessment also need a Fire Risk Assessment, EICR, and PAT testing on broadly similar review cycles. Our bundle pricing on combined visits typically saves 15–20% versus booking each service separately — driven by single-trip mobilisation rather than discount marketing.
Every Legionella risk assessor in the RiskSorted network is verified before their first booking. Verification includes:
When you book a Legionella risk assessment through RiskSorted, the booking is matched to the assessor with the right competence for your water system type, the closest postcode to your premises, current insurance, and capacity in your timeframe. Match-by-system-type is the discipline that distinguishes proper Legionella work from generic H&S consultancy — a hot-water-system specialist will not be matched to a cooling-tower site, and a cooling-tower specialist will not be wasted on a small office. Verification is repeated annually; assessors whose insurance or competence evidence lapses are removed from the matching pool until renewed.
Legionella is the compliance service where the gap between regulatory requirement and buyer understanding is widest. Most office managers, landlords, and small-business owners discover that they need a Legionella risk assessment when an insurance renewal flags it, a lease audit picks it up, or — worst case — after an outbreak in a comparable building. By that stage, the buyer is trying to procure a service they don't fully understand, in a market dominated by either generic H&S consultancies pretending to specialism they don't have, or water hygiene companies who write for engineers, not buyers.
The standard misconception: Legionella is only a concern for cooling towers and large industrial sites. The reality: Legionella bacteria can grow in any water system between 20°C and 45°C, and any aerosol-generating outlet — including a standard office tap, a shower head, or a hot drinks dispenser — can deliver an infectious dose. Standard offices on mains water are lower risk than hotels with cooling towers, but not zero risk. The legal duty to assess applies regardless.
The standard cost trap: Buyers shop on price for what they think is a paperwork exercise, not realising that an inadequate assessment from a non-specialist creates worse exposure than no assessment at all. A document that says 'low risk, no action required' from someone who doesn't actually understand the water system, written without proper schematic mapping or vulnerability assessment, is the sort of thing that gets discovered after an incident. The HSE's prosecution pattern in Legionella cases consistently shows that 'we had an assessment' is no defence if the assessment itself was inadequate or done by an incompetent assessor.
The standard frequency confusion: Buyers ask 'how often do I need to test the water?' when they actually need to ask 'when do I need to review the risk assessment, and what monitoring does the assessment recommend?' Routine sampling is not a legal requirement for most low-risk premises. Most offices need temperature monitoring and flushing of low-use outlets, not quarterly water sampling. The risk assessment specifies what's needed for your specific system.
What proper Legionella content looks like. RiskSorted's Legionella assessments include a full schematic of your water system (most non-specialist consultants don't draw one), an asset register of every relevant outlet (most don't compile one), a vulnerability assessment for your specific occupant profile (most apply a generic template), and a written scheme of control that you can actually operate (most produce control schemes that look impressive but are too generic to follow). The assessment costs slightly more than the cheapest available, and the saving over the lifetime of the asset is substantial — proper monitoring frequency rather than over-sampling, proper control framework rather than over-engineered chemistry, and proper defence in any subsequent investigation rather than a document that won't stand up to scrutiny.
Every booking through RiskSorted supports a UK Legionella Control Association member assessor or specialist water hygiene practice — not a generic H&S consultant adding Legionella to a service menu they're not properly competent to deliver. Compliance spend stays in the UK communities where the buildings stand, and the assessment quality reflects the genuine specialism the law expects.
Reviewed by RiskSorted's compliance team. RiskSorted's in-house team holds collective qualifications across NEBOSH General Certificate, IOSH Managing Safely, Fire Risk Assessment (PAS 79-1), and electrical compliance. All service guides are reviewed against current UK regulations and the latest editions of the relevant British and ACoP standards.
This page provides general guidance on UK compliance services and is not a substitute for professional advice. Specific compliance requirements should be confirmed with a qualified professional based on the particulars of your premises, business activities and applicable regulations.
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