Legionella is a pathogenic bacteria that can cause several different illnesses, the collective term for these illnesses is Legionellosis which includes the mild flu-like illness Pontiac Flu and the more serious pneumonia-type illness Legionnaires disease. 

GCW can provide:

  • A risk assessment of site water systems
  • Design a bespoke logbook and suitable maintenance program
  • Legionella training for inhouse monitoring and maintenance
  • Sample Analysis that is UKAS certified
  • Disinfection and chlorination to BS8558
  • GCW serve the South West and South Central England


About Legionella



Where can you get Legionnaires disease

Legionella can be commonly found (usually in low numbers) in natural water sources such as ponds, lakes, rivers and reservoirs. In conditions where there are low numbers and low temperatures the bacteria poses little health risk to humans.

Legionella can also be found in purpose-built water systems such as:

  • Hot and cold water system
  • Showers
  • Jacuzzis
  • Spa Pools
  • Cooling Towers
  • Evaporative Condensers

A contaminated purpose-built water system can produce favourable conditions for the legionella bacteria to grow and multiply. At temperatures of 20 to 45° the conditions become ideal for growth and multiplication.

The disease is contracted in most cases through inhalation of water droplets known as aerosols and the risks become greater in people over 45 years of age and / or with a weak or impaired immune system.

Legionella Risk Assessment



Under UK Health and Safety law, commercial organisations including residential and commercial landlords are responsible for the health and safety of employees and members of the public on their premises. The HSE L8 requires organisations and commercial building owners of whom have installed hot and cold water systems, should consider the risks from Legionella by carrying out a risk assessment.

The risk assessment will look at the current system and how it is used. It will then look at the current measures taken in maintenance and monitoring. This will include whether a ‘responsible person’ has already been appointed and whether existing control schemes are sufficient.


Should the outcome of the risk assessment conclude the system is of low risk then no further action may be necessary.

Where the risk assessment concludes the system is of a higher risk then a scheme will need to be put in place to help prevent, control and manage the risk.


Legionella Logbook

A logbook, either standard or bespoke may need to be created to assist with ongoing legionella risk management. The legionella logbook will be used to record and log all water management and legionella control data with monitoring and maintenance checkforms, a copy of the risk assessment, a full copy of the HSE L8 documentation and a list of service providers.


Legionella Testing

Where sampling / testing is required, GCW can provide sample analysis with UKAS certification. This would only normally be required if existing legionella controls are deemed insufficient or if the existing water system is concluded to be of high risk.


Legionella Treatment



GCW can provide complete disinfection and chlorination services  to existing pipework and water systems conforming to British Standards BS8558. Our staff have over 30 years in the water utilities industry.

Further guidance can be found from the Health and Safety Executive website



Legionella Service Areas Covered by GCW


 Services in Gloucestershire

Lydney, Coleford, Gloucester, Tewkesbury, Chipping Campden, Stow on-the wold, Cheltenham, Brockworth, Northleach, Stroud, Durlsey, Wotton-under-Edge, Badmington, Tetbury, Cirencester, Bibury, Lechlade.

 Services in Wiltshire

Amesbury, Bradford on Avon, Calne, Chippenham, Corsham, Cricklade, Devizes, Ludgershall, Malmesbury, Marborough, Melksham, Mere, Royal Wootton Bassett, Salisbury, Swindon, Tidworth, Trowbridge, Warminster, Westbury, Wilton.

Services in Somerset

Axbridge, Bath, Bridgwater, Burnham on Sea, Chard, Cheddar, Clevedon, Crewkerne, Dunster, Exmoor, Frome, Glastonbury, Ilminster, Langport, Minehead, Nailsea, Porlock, Radstock, Shepton Mallet, Somerton, Street, Taunton, Watchet, Wellington, Wells, Weston Super Mare, Wincanton, Wiveliscombe, Yeovil.

 Services in Dorset

Abbotsbury, Beaminster, Blandford Forum, Bournemouth, Bridport, Cerne Abbas, Christchurch, Corfe, Castle, Dorchester, Evershot, Gillingham, Kimmeridge, Lulworth, Lyme Regis, Milton Abbas, Moreton, Poole, Portland, Puddletown, Purbeck, Shaftesbury, Sherborne, Stalbridge, Sturminster Newton, Swanage, Tolpuddle, Tyneham, Wareham, Weymouth, Wimborne, Wool, Yetminster.

Services in Devon

Appledore, Ashburton, Axminster, Barnstaple, Beer, Bideford, Bovey Tracey, Brixham, Buckfastleigh, Budleigh Salterton, Chumleigh, Clovelly, Cullompton, Crediton, Dartmouth, Dawlish, Exeter, Exmouth, Holsworthy, Honiton, Ilfracombe, Ivybridge, Kinsbridge, Lifton, Lyme Regis, Lynton, Newton Abbot, Newton Ferrers, Okehampton, Ottery St Mary, Paignton, Plymouth, Salcombe, Seaton, Sidmouth, South Molton, Tavistock, Teignmouth, Tiverton, Topsham, Torquay, Totnes, Woolacombe.

Services in Cornwall

Camborne, Helston, Marazion, Mullion, Penzance, St Ives, The Lizard, Hayle, Lands End, Mousehole, Porthleven, Sennen, Charlestown, Fowey, lostwithiel, Penryn, Rame, St Mawes, Truro, Falmouth, looe, Mevagissey, Polperro, St Austell, The Roseland, Boscastle, Bude, Camelford, Crackington Haven, Mawgan Porth, Newquay, Padstow, Perranporth, Polzeath, Port Isaac, Rock, St Agnes, Tintagel, Wadebridge, Watergate Bay.