HSG179 is one of those documents that every commercial pool operator in the UK has heard of, but surprisingly few have actually read cover to cover. It is the HSE's guidance document for managing health and safety in swimming pools, and it is the standard that Environmental Health Officers and the HSE itself will measure you against if something goes wrong.
The current version is the 4th edition, published in 2018. It is free to download from the HSE website, and if you run a commercial pool and have not read it, you should. But it is also a fairly dense document, so here is a practical breakdown of what it actually requires and what that looks like in the real world.
What HSG179 actually is (and is not)
First, something that surprises a lot of people: HSG179 is guidance, not law. There is no specific legislation in the UK that regulates swimming pools directly. Instead, pool operators are covered by general health and safety legislation, primarily the Health and Safety at Work Act 1974 and the Management of Health and Safety at Work Regulations 1999.
What HSG179 does is interpret those general legal duties in the context of swimming pools. It tells you what "reasonably practicable" looks like when you are running a pool. And here is the important bit: if an enforcing authority investigates an incident at your facility, HSG179 is the benchmark they will use. If you were following it, you are in a strong position. If you were not, you have a problem.
PWTAG guidance (the Code of Practice and the Swimming Pool Water book) complements HSG179 by going into much more detail on water treatment and quality. Between the two, you have the full picture of what is expected.
Who enforces it
Enforcement of health and safety in commercial pools falls to two bodies. The HSE covers pools in government buildings, factories, and similar premises. Local authority Environmental Health Officers handle everything else, which means hotels, leisure centres, schools, private sports clubs, and spas.
Each local authority makes its own arrangements for inspections and water quality monitoring. Some are proactive and visit regularly. Others are reactive and only turn up after a complaint or incident. Either way, you need to be ready at all times, because you will not always get advance notice.
The enforcing authorities have the power to issue improvement notices (requiring you to fix something within a set timeframe) or prohibition notices (requiring you to close the pool immediately if there is an imminent risk to health). A prohibition notice means the pool stays closed until the issue is resolved and the authority is satisfied.
The Pool Safety Operating Procedure (PSOP)
This is the centrepiece of HSG179 compliance. Every commercial pool must have a written Pool Safety Operating Procedure, and it needs to consist of two parts: a Normal Operating Plan (NOP) and an Emergency Action Plan (EAP).
Normal Operating Plan (NOP)
Your NOP sets out how the pool operates on a day to day basis. It should cover:
Pool details and dimensions: A factual description of your pool or pools, including depths, dimensions, features (slides, wave machines, moveable floors), and a scaled plan showing the layout.
Potential hazards: Every hazard you have identified through your risk assessment, along with the controls you have in place. This includes water quality risks, slip hazards, entrapment risks from drain covers or grates, diving injuries, and anything specific to your pool design.
Supervision arrangements: How many lifeguards or supervisors are on duty, where they are positioned, rotation schedules, and maximum bather loads. If your risk assessment determines that constant poolside supervision is not required (for example, a small hotel pool with restricted access), the NOP should explain why and what alternative arrangements are in place.
Water quality management: Your testing regime, who is responsible, acceptable parameter ranges, and what happens when a reading is out of specification. This should reference your PWTAG compliance procedures.
Staff training and competence: What qualifications your staff hold, refresher training schedules, and who is authorised to do what. This includes lifeguard qualifications, first aid training, and pool plant operation competence.
Operating procedures: Opening and closing routines, cleaning schedules, changing room management, and any specific rules for different sessions (lane swimming, lessons, public sessions).
Maximum bather loads: Calculated based on pool size, depth, lifeguard numbers, and the type of activity taking place. HSG179 does not give a single formula for this. It expects you to work it out through your risk assessment, taking into account your specific pool, users, and supervision arrangements.
Emergency Action Plan (EAP)
Your EAP covers what happens when things go wrong. It needs to be specific to your facility, not a generic template pulled from the internet. The plan should cover:
Serious injury or fatality in the water: Rescue procedures, resuscitation, calling emergency services, clearing the pool, preserving the scene.
Pool water contamination: Faecal releases (solid and liquid), blood, vomit. What is the closure procedure? How long does the pool stay closed? What testing do you do before reopening? PWTAG has specific guidance on contamination response times that your EAP should reflect.
Chemical incidents: Gas leaks from chlorine storage, chemical spills, dosing system failures. Where are the shut-off points? Who is trained to deal with chemical emergencies? What PPE is available?
Fire and evacuation: Getting people out of the water and out of the building safely, including people who cannot swim or who have disabilities.
Structural failure: What happens if a ceiling panel falls, a light fitting drops into the water, or a moveable floor or boom malfunctions.
Loss of power or water supply: How do you maintain safety if the plant fails, the lights go out, or you lose water circulation.
The critical thing about your EAP is that staff need to know it. A beautifully written document sitting in a folder in the manager's office is worthless if the lifeguard on duty at 7pm on a Saturday does not know what to do when someone has a cardiac arrest in the deep end. Regular drills, training, and refresher sessions are not optional.
Risk assessment
HSG179 requires a comprehensive risk assessment covering all aspects of pool operation. This is not a one-off exercise. Your risk assessment needs to be reviewed regularly and updated whenever something changes, whether that is a new activity, new equipment, a change in user profile, or an incident that reveals a hazard you had not considered.
The risk assessment should cover the pool itself, the surrounding areas (changing rooms, showers, spectator areas), the plant room, chemical storage, and any ancillary facilities.
For the risk assessment to be meaningful, it needs to be done by someone who understands pool operations. A generic risk assessment template filled in by someone who has never stood in a plant room is not going to cut it.
Water quality and treatment
HSG179 covers water quality at a high level and defers to PWTAG for the detailed guidance. But it does make clear that pool operators must have effective systems for monitoring and maintaining water quality, and must keep records of all testing and corrective actions.
The key requirements from HSG179's perspective are that water must be properly disinfected and filtered, that testing must be carried out regularly, that out-of-specification results must be acted on, and that records must be kept.
If you want the full detail on testing frequencies, parameter ranges, and microbiological sampling requirements, see our PWTAG Compliance Checklist for a practical breakdown.
What an inspector will actually ask for
When an EHO or HSE inspector visits your facility, they are not just looking at the water. They are looking at the whole management system. Based on real inspection experiences, here is what they typically want to see:
Your PSOP (NOP and EAP), and evidence that staff know what is in it. They may ask a member of staff what they would do in a specific scenario to check whether training is actually landing.
Water quality records for at least the last three months. They want to see consistent testing, results within acceptable ranges, and documented corrective actions when things were out of spec. Gaps in your records are a red flag.
Microbiological sampling results showing monthly lab testing (weekly for hydrotherapy pools). If you cannot produce these, expect follow-up action.
Risk assessments that are current, specific to your facility, and signed off by someone competent.
Staff training records showing qualifications, dates, and refresher schedules.
Maintenance records for plant and equipment, including filter backwashing, dosing system calibration, and any repairs or replacements.
Chemical storage and COSHH assessments covering every chemical on site, with material safety data sheets available.
Incident records showing how you have dealt with contamination events, injuries, or near misses.
The inspectors who really know their stuff will also look at the physical state of your plant room. Leaking pipes, corroded equipment, unlabelled chemical containers, and general disorder all tell a story about how seriously management takes pool safety.
The practical reality
The honest truth is that HSG179 compliance is not complicated. It is thorough, and it requires discipline, but none of it is unreasonable. The operators who get caught out are usually not the ones who do not care. They are the ones who let things slip gradually. Testing gets missed on a busy day. The EAP does not get updated when a new pool feature is installed. Staff training lapses because the budget is tight.
The key is having systems that make compliance the default rather than something that requires extra effort. If your testing regime is built into the daily routine, if your records are easy to keep and easy to find, and if your staff are properly trained and regularly refreshed, you are already doing most of what HSG179 asks.
How AquaAssure supports HSG179 compliance
We built AquaAssure to make the record-keeping and monitoring side of HSG179 compliance as painless as possible. Every water test is logged with automatic range checking and instant alerts when readings are out of specification. Corrective actions are recorded alongside the original reading, so your compliance trail is always complete and audit-ready.
Equipment maintenance scheduling, chemical inventory tracking, and compliance reporting all sit in one place, accessible from a tablet or phone. When an inspector asks to see your records, you can pull them up in seconds rather than digging through filing cabinets.
The platform was built by a working facilities manager at a Premier League academy, designed around the actual requirements of HSG179 and PWTAG, and tested in a real operational environment. If you are managing compliance on paper or spreadsheets and want to see a better way, book a demo and we will walk you through it.