INFORMATION NOTE No 353: MICROBIOLOGICAL TESTING First issued: January 2007 Updated: June 2010 ABOUT ISRM This is one of a series of Information Notes produced by the Institute of Sport and Recreation Management, the leading professional body for people managing and operating sports and recreation centres. These Information Notes have been compiled by experts in their fi eld and are designed to provide introductory guidance on a range of issues for people working in the industry. ISRM members can read and download all the Information Notes at ISRM 2010
WHEN IT COMES TO WATER TESTING, JUST WHAT ARE THE RESPONSIBILITIES OF THE POOL MANAGER? This information note offers the pool manager comprehensive guidance based on expert advice by ISRM and the independent Pool Water Treatment Advisory Group What is the pool operator s responsibility towards pool water microbiological testing and interpretation? This information note summarises, updates and supersedes the advice given in previous notes. The guidance is based upon ISRM s own expertise, body of knowledge, and the following: The work of the independent Pool Water Treatment Advisory Group (PWTAG), of which ISRM is a founder and executive member; specifically, their definitive guide Swimming Pool Water Treatment and Quality Standards plus their British Standards Institute (BSI) PAS 39. The guidance of HSG 179 Managing Health and Safety in Swimming Pools, plus the Health and Safety at Work Act and other relevant legislation. ISRM recommends that the operators of swimming pools DO NOT carry out the analysis of microbiological tests themselves The pool operator has responsibility for the safe microbiological condition of their pool. They must ensure that appropriate testing is carried out to ensure a safe condition. In doing so they are meeting their responsibilities under the: Health and Safety at Work Act 1974 (HSAW) Environmental Protection Act 1990 The Control of Substances Hazardous to Health Regulations (COSHH) 2002 Health and Safety (Enforcing Authorities) Regulations 1998 PAS 39: 2003. Management of Public Swimming Pools, Water Treatment Plant and Heating and Ventilation Plant Code of Practice. (now withdrawn but still available to purchase and currently valid) HSG 179 Managing Health and Safety in Swimming Pools BS EN 15288 2 2007 Swimming Pools Safety Requirements for Operation Compliance with the standards The responsibility for ensuring compliance with health and safety legislation at swimming pools lays with either the Health and Safety Executive (HSE) or the local authority environmental health departments, depending upon the main activity of the premises. The HSE enforces pools owned, managed or occupied by local authorities and pools in local authority schools. It does not carry out microbiological testing of these pools, but in the event of a reported problem or incident then the HSE would look for evidence that the pool operator has discharged their responsibilities for testing properly. Privately operated (not domestic) pools, such as those in hotels, holiday camps and fitness clubs, are the responsibility of environmental health departments (EHDs). Environmental health department staff will proactively test swimming and spa pools in their area to ensure compliance with microbiological standards The role of environmental health departments Environmental health officers have right of entry into all pools, both private and publicly-operated, under the Environmental Protection Act 1990, and they may undertake bacteriological sampling if they deem it necessary. The EHO may also carry out regular, routine testing at pools operated by local authorities. In fact, many local authority pools have a mutual arrangement with their local EHD for bacteriological testing. However, the actions of local EHDs do not take away the operator s responsibility for ensuring regular microbiological testing by an accredited laboratory. This accountability stems from the general guidelines under HASAW and COSHH regulations, and is clearly outlined in the HSE Managing Health and Safety in Swimming Pools HSG 179, as the following extract explains: Disinfectants and bacteriological water quality 359 In order to establish that the pool is without risks to the health of those using it, pool operators will need to ensure, under the COSHH Regulations, that they have adequately controlled the risks from exposure to microorganisms. To do this, adequate disinfecting of the pool will need to take place and bacteriological sampling will be required. 360 Bacteriological sampling will need to be undertaken monthly in pools in use all year round. Bacterial levels should be zero (or near zero) as a baseline. More frequent samples will be necessary where deterioration in water quality occurs. Pools that are less frequently used should be checked before use and then monthly throughout their operational period.
In the interests of independently validated, accurate and robust record-keeping, which may be vital in the case of litigation, ISRM recommends that the operators of swimming pools DO NOT carry out the analysis of microbiological tests themselves. The analysis of samples should instead be carried out by a reputable and independent organisation. This will most likely be either an accredited laboratory or through the local Environmental Health Department. European standards BS EN 15288-2 2007 Swimming Pools Safety Requirements for Operation under the section on Monitoring physical, chemical and microbiological quality of pool water says that procedures for monitoring the pool water quality shall include statements that prescribe: the water quality parameters to be achieved (including ph, clarity, temperature, disinfection level, bacteriological quality); the correct way of sampling the water, for both automatic and manual testing equipment; the type, method and frequency of each test; and the proper way of recording and storing the related findings. ISRM National Pool Safety Award (NPSA) The ISRM National Pool Safety Award is based upon BSI PAS 39 and 65. While both these documents are now withdrawn, the NPSA still uses currently valid versions to set the criteria to achieve this award. Undertaking this award is a very thorough means of demonstrating compliance with an operator s responsibilities. PWTAG microbiological standards PWTAG is the independent, voluntary regulator in the UK for swimming pool and spa pools and is recognised as such by the ISRM, the Health Protection Authority and the HSE. PWTAG has agreed the following standards for the assessment of microbiological quality of pool water: How frequently should testing occur? In general: a routine, monthly test will sufice for swimming and spa pools; and weekly testing for hydrotherapy pools. Failure to comply with the target levels for one or more of the parameters is often a passing phenomenon Samples should also be taken: before a pool is used for the irst time; before it is put back into use after it has been shut down for repairs or cleaning, or after an emergency/ incident; if there are dificulties with the treatment system; when there is contamination; and as part of any investigation into possible adverse effects on bathers health. (If health effects are suspected, the consultant in communicable disease control, environmental health officer and director of the testing laboratory should be informed.) Who should carry out tests? In order to ensure their safety, people doing microbiological monitoring should be properly trained and work to a written protocol supported by a COSHH assessment. Microbiological analysis should be carried out in appropriately accredited laboratories, such as UKAS laboratories.
How should testing be carried out? The ph value and the concentration of free and total disinfectant in the pool water should be measured when the microbiological sample is collected. Microbiological samples should be taken beginning at a depth of 200mm - 400mm below the surface of the pool. The results of routine microbiological sampling should always be interpreted in conjunction with: chemical tests performed on site and/or in the laboratory at the time of sample collection; and a review of the maintenance records for the pool, including records of the ph, residual disinfectant levels, mechanical failures and water appearance and other untoward events. It should be noted that failure to comply with the target levels for one or more of the parameters is often a passing phenomenon. EXTRACT FROM BSI CODE OF PRACTICE PAS39W Microbiological contamination of the pool water can result in pathogenic (disease producing) microorganisms causing infections to bathers. These contaminants can be introduced into pool water from bathers, from the pool fi lters, or occasionally from defects in pool engineering. Samples of pool water should be tested at appropriate intervals to ensure that all is well. SWIMMING POOL WATER MICROBIOLOGICAL STANDARDS Samples should be tested for aerobic colony count, coliforms, Escherichia coli and Pseudomonas aeruginosa. Colony count (37ºC for 24 hours) Not more than 10cfu/ml Coliforms Absent in 100ml although less than 10 per 100ml is acceptable, provided it does not happen in consecutive samples. There are no Escherichia coli. The colony count is less than 10cfu/ml and the residual disinfectant concentration and ph values are within the recommended ranges Escherichia coli Absent in 100ml Pseudomonas aeruginosa Absent in 100ml for all spas and whirlpools (and as optional additional quality assurance in conventional pools) Aerobic colony count The aerobic colony count (ACC), sometimes called the total viable count, colony count, or plate count, is a general test that indicates whether the pool disinfectant regime is effective in controlling contamination under operational circumstances. The colony count should be carried out in accordance with BS EN ISO 6222 (BS 6068-4.5) but with incubation at 37 C for 24 hours. These test conditions are set to isolate the range of organisms that can colonise in the mouth and on the skin of bathers. The ACC can increase where there is a higher bather load, reduced chlorine residual or where there are defects in water treatment. The aerobic colony count should normally be 10 or less colony forming units (cfu) per millilitre of pool water. If a colony count above 10 cfu/ml is the only unsatisfactory microbiological result, and residual chlorine and ph values are within recommended ranges, the water should be re-tested. Total coliforms Coliforms within swimming pools can be considered as an indication of faecal contamination or poor hygiene (eg. contamination from shoes or leaves in outdoor pools). Their presence indicates that the treatment has failed to remove this contamination. In isolation, coliforms do not usually cause disease so the presence of Escherichia coli is a better indication of faecal contamination. Coliforms are sensitive to disinfectant and should be absent in 100 ml of pool water. A repeat sample should be taken whenever coliforms have been detected. A coliform count of up to 10 cfu/100 ml is acceptable provided that: coliforms are not found in the repeat sample;
the aerobic colony count is less than 10 cfu/ml; there are no E. coli present; and the residual disinfectant and ph values are within recommended ranges. Escherichia coli Escherichia coli is normally present in the faeces of most humans, mammals and birds. It is widely used as a specifi c indicator of faecal contamination as it is unable to grow within the environment. The presence of E. coli in swimming pool water is an indication that faecal material has entered the pool water from contaminated skin, or from faecal material that has been accidentally or deliberately introduced. It also indicates that treatment has failed to remove this contamination. E. coli should be absent in a 100 ml sample. However, because most bathers will have some faecal contamination on their skin, particularly if they have not showered before bathing, a single positive sample may be the result of recent, superfi cial contamination by a bather that has not yet been decontaminated by the disinfectant residual. A repeat sample should then be taken. Pseudomonas aeruginosa Pseudomonas aeruginosa can grow in untreated waters and biofi lms. It can cause skin, ear and eye infections when present in large numbers. Outbreaks of skin infections have been linked to swimming pools and spa pools. The pool should be closed if there is chemical or physical evidence of unsatisfactory disinfection Well-operated pools should not normally contain P. aeruginosa. If the count is over 10 P. aeruginosa per 100 ml, repeat testing should be undertaken. Where repeated samples contain P. aeruginosa, the fi ltration and disinfection processes should be examined to determine whether there are areas within the pool circulation where the organism is able to multiply. Where counts exceed 50, pool closure should be considered. CLOSING POOLS When to close the pool: If one of the microbiological results is unsatisfactory, the test should be repeated as soon as possible. If the second result is also unsatisfactory, the pool s management and operation should be investigated and the test repeated. The investigation may require the help of the laboratory that does the tests, the district council environmental health department, or an independent consultant. If results are still unsatisfactory after the investigation and a third series of tests, immediate remedial action is required that may necessitate pool closure. For example, the pool should be closed if there is chemical or physical evidence of unsatisfactory disinfection. The pool should be closed if microbiological testing discloses gross contamination. GROSS CONTAMINATION MEANS ONE OF TWO THINGS: 1) E. coli over 10 per 100ml PLUS either a colony count over 10cfu per ml or P. aeruginosa over 10 per 100ml (or, of course, both) 2) P. aeruginosa over 50 per 100ml and a colony count over 100 per ml.