Do i need to disinfect my Cold Water System?
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Yes, anyone with a Cold Water System should maintain good hygiene of their tanks.
Some of the problems that can occur in Cold Water Systems can be put down to the property of water. If water is too acid it can lead to the corrosion of pipes, where as hard water leaves deposits that can harbour harmful bacteria.

Getting it right!

Water quality can measured in many different ways, e.g. looking at the PH Value you can determine that acidic content.

Here are a few of the ways we measure water quality and why:

PH Testing.
Slightly acidic water will break down materials in plumbing systems resulting in a build up of silt and debris, favourable to Legionella.

Legionella is a harmful bacteria that thrives in water with a Ph value between 6.5 - 7.5

Conductivity.
Conductivity is a measurement of the salt content in a water solution; relating to the total dissolved solids. Low conductivity tends to mean soft water meaning fewer deposits have been dissolved. Water conductivity is higher in hard water geographical areas.

Calcium Hardness (Hard or Soft Water).
Commonly known as Lime scale, occurs through high temperatures, high PH and high conductivity. Lime scale can lead to poor heat transfer and blockages in hot water systems. Lime scale encourages the growth of harmful bacteria, such as Legionella.

Turbidity.
Turbidity is a measure of the materials in a suspended water solution. Domestic systems can be affected by a presence of Iron (Fe), Copper (Cu), scale, particles and bio-film. Particles are deposited in still waters and present the ideal breeding ground for harmful bacteria.

Dissolved Oxygen.
Dissolved oxygen is caused by poor maintenance or low water quality, making water corrosive and causing problems for galvanised tanks. More modern domestic tanks tend to be coated against this.

Over 300 tests can be performed on a sample to measure all possible contaminants.

Fig.1, Zinc Oxide deposits on stagnant water.

Fig. 2, Corrosion at the bottom of a CWSC.

Fig. 3, Corrosion under a CWSC.

All these examples are usually tested for.

Legionella

Legionella can cause Legionnaires' Disease and Pontiac Fever.
Approx. 200 - 250 cases are reported each year in the U.K; Considered underestimated. Over half of these cases are attributed to foreign travel.

Conditions to promote the growth of Legionella are:
	Water temperatures between 20 ° C and 45 ° C (optimal 35 ° C - 46 ° C)
	Stagnant Water
	PH Range of 6.5 to 7.5
	Sediment in water supporting microbe growth
	Microbes, Lime scale, Algae, Protoza and others
Conditions to reduce the growth of Legionella are:
	Water temperatures below 20 ° C or above 60°C
	Well designed systems to prevent - stagnant water build up of sludge, scale or microfilm

Preventing Legionnaires' Disease.
	Keep water systems clean; including regular disinfection. (recommended every 12 months)
	Keep water moving
	Keep water hot (above 60 ° C)
	Keep water cool (below 20 ° C)

Legionnaires' Disease (A from of Pneumonia)

The bacteria are commonly found in natural water supplies such as rivers and lakes. Mains water is treated but not sterile and can be re-infected through plumbing systems.

The hot or cold water system installed in the building determines the outcome of the final water quality.

Legionnaires' Disease can affect anybody but those particularly susceptible can include:
	People over 45 years
	Suppressed Immune system sufferers
	Heavy smokers or drinkers
	People with weak lungs or kidney disease
Males are twice as likely to contract the disease.
Initial symptoms can include:
	High Fever
	Chills
	Headache
	Muscular pain
May also experience a dry cough; suffer breathing problems or diarrhoea and vomiting.
Incubates in humans within 2 - 10 days (usually 3 - 6) and may respond to medication.