UV Water Treatment

An ultraviolet unit passes water along a quartz sleeve containing a UV lamp. The dose the water receives — measured in mJ/cm² and set by flow rate, lamp output and water clarity — reduces the ability of microorganisms to reproduce. It adds nothing to the water, changes neither taste nor conductivity, and leaves no residue.

Two conditions it depends on

Clear water. Turbidity shadows microorganisms from the lamp. A UV unit fitted behind an unfiltered well supply delivers a fraction of its rated dose, which is why sediment filtration always comes first.

Correct flow rate. Dose falls as flow rises. A unit rated for 2 m³/h passing 4 m³/h is not performing at half strength — it is below the threshold that matters. Size on peak flow, not average.

Lamp and quartz sleeve

A UV lamp keeps lighting long after its useful output has fallen. Lamps are replaced on a time basis — commonly around 9,000 operating hours — not when they stop glowing. The quartz sleeve is cleaned at the same interval; scale and iron film on the sleeve cut transmission just as turbidity does.

Lamps and sleeves are consumables and sit outside warranty cover. The housing, ballast and control carry a 2-year warranty.

Where a UV stage belongs

On well and tank supplies, and on building inlets where water stands in a roof tank. On treated mains water it is generally unnecessary. It is always the last stage before the point of use — anything downstream of the lamp can reintroduce what the lamp addressed.