Monitoring and Sampling For Hot and Cold Water Systems

Monitoring and sampling for hot and cold water systems

Legionella monitoring should be carried out where there is doubt about efficacy of control regime or where recommended temperature, disinfectant concentrations or other precautions are not being consistently achieved throughout the system.
Where monitoring for Legionella is considered appropriate in hot and cold water system, sampling should be carried out in accordance with BS7592.
Monitoring includes hot and cold water system temperatures and other parameters accelerating the contamination, amplification, transmission, exposure, susceptibility.

Regular monitoring and inspection
As part of this service we will provide:
  • Weekly flushing of little used outlets
  • Monthly temperature monitoring of the hot and cold sentinel outlets including the flow and return temperatures of the calorifiers
  • Monthly monitoring of the supply temperature to the MV
  • Quarterly shower head cleaning and disinfection
  • Half yearly water sampling
  • Half yearly monitoring of store and ball valve temperatures of the cold water storage tanks
  • Half yearly temperature monitoring of the city mains
  • Annual Tank condition report with photographs
  • Annual blow down and removal of deposits from calorifiers
  • Annual fail safe check and strainer cleaning and disinfection of the TMVs
  • Annual sampling from the calorifiers
  • Annual Auditing
  • Review of the risk assessment in evry two years
  • Sample analysis report (UKAS)
  • Access to your soft copy folder maintained in our website
  • Access to our online library
  • Free archiving of your documents for the next 5- 7 years (legal requirement)

Following a Legionella Risk Assessment a written monitoring plan should be prepared to control the identified risks of Legionella. This plan should identify the chosen control measure, for example, avoiding water temperatures between 20°C and 45°C and how this will be achieved. The plan should then be implemented, regularly managed and monitored. The ACOP L8 says "the risk from exposure to legionella should be prevented or controlled; precautions should include the use of water treatment techniques".
Temperature monitoring
The most favourable temperature for the proliferation of legionella bacteria is between 20°C and 45°C.

The city mains supplying temperature normally sets below20°C. But the stored water temperature could be raised along with the ambient temperature due to so many reasons such as lack of insulation, stagnation, improper air vents, location of the cold water storage tank etc.

The flow temperature from water storage vessel (calorifiers) must be maintained between 60°C and 62°C and the return must be above 50 °C but due to poor condition of the storage vessel or lack of insulation may cause the temperature to fall below the required threshold of 50°C.

  • As part of this service we will provide:
  • Monthly monitoring of the remaining 10% outlet’s temperature
  • Monthly monitoring of the flow and return temperatures of the calorifiers
  • Monthly monitoring of the supply temperature to the calorifier
  • Half yearly monitoring of the stored and ball valve temperatures
  • Half yearly monitoring of the City main’s temperatures
  • Annual monitoring of the stored and ball valve temperatures
  • Annual monitoring of the City main’s temperatures
  • Advice the client to take corrective actions if the temperatures falls within the threshold of 20 -45°C
Microbiological analysis
As part of this service we will provide:
  • Temperature Record
  • Certificate of Compliance
  • An annual tank condition report with photographs
  • Test results (UKAS) with interpretation and advice on required remedial actions
  • Access to your soft copy folder maintained in our website
  • Access to our online library
  • Free archiving of your documents for the next 5- 7 years (legal requirement)
Water Sampling is often a crucial part of any Legionella Control Scheme, by measuring the effectiveness of the control measures. The ACoP L8 says "the risk from exposure to legionella should be prevented or controlled and that the precautions taken should be monitored to ensure that they remain effective". Whilst routine Microbiological sampling is not always necessary as the water supplied to a building should be fit to drink. Where there is the potential for Micro-organisms to grow in areas of hot and cold water systems Microbiological sampling should be carried out:
  • Where drinking water (potable) is stored
  • Where systems treated with biocide and storage and distribution temperatures are lowered
  • Where control measures (correct temperatures) are not consistently achieved
  • Identification of potential hazards and associated risks
  • Where a Legionella outbreak is suspected
  • Where building occupants are deemed at risk, e.g. those who’s immune system is suppressed
  • Where the Legionella Risk Assessment findings recommend Microbiological sampling will aid monitoring
Total Viable Counts (TVC)
  • Basic test of water quality
  • Determines overall levels of contamination
  • Essential that TVC falls within recommended guidelines for the control of Legionella
Coliforms (Coliform & Faecal) & E-Coli
  • Coliform - Indicates potential contamination of water source
  • Coliform - Evaluates general quality of the water
  • Faecal Coliform - Indicates contamination from human / mammal waste product
  • E-Coli – short lived in water so is an indication of recent contamination
  • E-Coli – bacteria of the lower intestine. Rapidly detected on analysis and its detection indicates similar bacteria may be present
Pseudomonas Aeruginosa
  • Common bacterium easily colonises water systems and can produce a biofilm which affects taste and colour of water. This biofilm also produces a habitat and nutrient source for Legionella bacteria
Private Drinking Water Supplies (Boreholes)
  • Sampling suites in accordance with the private drinking water regulations 2009
  • Consultation on analysis results
Rainwater Harvesting (Grey Water) Systems
  • Sampling in accordance with BS 8515:2009 and the Environment Agency guidance
  • Consultation on analysis results
Swimming Pool & Spa Pool Waters
  • Sampling in accordance with PWTAG, Pool Water Treatment Advisory Group
  • Consultation on analysis results
Closed Systems
  • Sampling in accordance with BISRA guidance
  • Consultation on analysis results
  • Chemical dosing of systems
  • We work in strict accordance with current legislation & guidance
  • A qualified engineer will attend site and determine sample quantities, types and locations
  • UKAS accredited laboratory for analysis
  • We will fully explain sample results and any impact these results may have on your water systems along with any further actions deemed necessary
  • Legionella sampling and all types of water testing can be carried out on a one-off or contract basis
  • We use detailed, but easy to follow reporting systems
  • We have many years experience in Legionella control and water treatment
  • We provide a cost effective and efficient service
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