• Aquarius Drilling
  • Aquarius Drilling
  • Aquarius Drilling
  • Aquarius Drilling

Ultraviolet Disinfection for Dam and Rain Water



Private Water supplies are always at risk of bacteria contamination.  This can make people quite ill. 

Rainwater and Tank water

Rainwater is well known as also potentially a high risk for contamination of any water supply during the catchments and reticulation.  It falls free from the sky, drops on roofs, flows into guttering, collects bird poo laden with bacteria, dust, dirt, tannin or colour from leaves lying in the guttering.

Rainwater carries very little mineral base and is aggressive in behavior so what it flows against is what is absorbed.  If the roof is inert such as colourbond, or properly sealed roof construction then it cannot absorb much more than described previously (bacterium) and that is enough to cause fouling. 

Other roofs where various types of metals are present such as copper, aluminium, zinc, etc will cause all those metals to be absorbed by the flow of water and this again renders the water non-potable.

Bacteria grows in Plumbing

The private water supply then flows through down pipes which are full of bio-film from all contaminants as previously mentioned and fouls it further with water that has been left sit from the previous rainfall event and that bacterium has grown to high levels and it can really create quite a strong earthy odour at this moment. 

Storage and reticulation

The rainwater is then stored and reticulated through plumbing to taps for use. 

Bio-film growth

The bio-film grows faster on the inner walls of the delivery pipes as it is in a tight area.  The bacteria explode in number and starts forming a community developing a protective membrane over itself on the inner walls of a pipe and we see or feel it as slime.

It develops faster and more often on regular use taps and more so in hot water services where it is warmed up so that it can grow even faster.  When developing the membrane covering it changes form from one to another and during warming by water heaters.

Bacteria in excess of 30,000 plus colony forming units in 1ml can form into salmonella. So, is your water supply safe to drink? 

Responsibility on suppliers

All persons supplying drinking water to the general public in any premises must take the appropriate steps to ensure that such drinking water is potable. There are guidelines called the Safe Water Drinking Guidelines as adopted by all states.  Some of these bacterium types are listed below to assist you to have a basic understanding.


Esherica Coli (E Coli) should not be detected in 100ml of water of drinking water and if detected immediate action should be taken. Salmonela grows out of E high Coli levels Legionella is a risk factor from warm water systems where mist spray is apparent and can come from E Coli but mores so the bacterium following.  Legionella can cause Legionnaires disease.

The effect of bacteria contaminated water consumed by persons will show as stomach aches, ear aches and lethargy in that person.

Ultra Violet

In the simplest terms this method produces intense ultra violet waves of light that are contained in a chamber with water flowing around.  The water supply needs to be extremely clean for this to be effective as it will not pass through sediment or colour particles but will simply bounce off and the kill or disinfection effect is lost.

Effective filtration prior is critical.  Ultra Violet carries no residual ability outside the chamber.  It is quite passive in operation.

The plumbing down-line must be disinfected after installation.  This is usually performed by a potable chemical that leaves no residue.

Installation and Commissioning of Ultra Violet

Once the system is installed proper commissioning is achieved by using a biocide to strip all possible bacteria from places even within the U V chamber down to every last point of use in all plumbing. 


The intervals for UV lamp replacement and cleaning should not exceed 12 months.  There are uses where the service life is so critical that require service to be more often.

Maintenance includes, stripping the system, cleaning, changing O rings as required then installing the new lamp and re-starting.