This question comes up constantly among New Zealand homeowners looking at UV water systems. Understanding what UV light actually does helps avoid expensive mistakes when choosing water treatment. The short answer might surprise many people who assume UV handles everything.
Why Carbon Filters Handle Chlorine Effectively?
Carbon filtration removes chlorine through a process called adsorption. Water flows through coconut shell activated carbon, and chlorine molecules stick to the carbon's porous surface. This happens because carbon has an enormous surface area - just four grams covers a football field.
The process also eliminates the harsh chemical smell and improves taste dramatically. Wellington and Auckland mains water users notice the difference immediately after installing proper carbon filters.
Carbon also removes chlorine byproducts, pesticides like Roundup, herbicides, and volatile organic compounds. These chemicals cause taste and odour problems that UV light cannot address. The 5-micron carbon filter works specifically for these chemical contaminants.
The Fluoride Challenge in Water Treatment
Fluoride removal presents bigger challenges than chlorine. Standard activated carbon filters cannot effectively remove fluoride because fluoride molecules are extremely small. Many New Zealand councils add fluoride to mains water at 0.7-1.2 parts per million. Some people want this removed for personal health reasons. Standard water filtration systems with only carbon and UV will not accomplish fluoride removal effectively.
How do Complete Water Systems Work Together?
Professional UV water filtration systems use multiple stages working together. Each stage handles specific contaminants that other stages cannot remove. This layered approach protects health better than single-method systems.
A typical setup includes three or four stages. The first pleated 5 micron filter removes sand, sediment, and broken-down leaves. The second carbon 5 micron filter removes taste, smell, discolouration, and chemicals entering from the roof. The third melt-blown 1 micron filter catches small floating matter.
Finally, the UV chamber sterilizes bacteria and viruses after water passes through clean filters. This sequence matters tremendously. Dirty water blocks UV light from reaching microorganisms, so filtration must happen first. Systems designed properly ensure UV light penetrates water effectively.
Why Filtration Must Come Before UV Treatment
Water turbidity affects UV effectiveness dramatically. Turbidity means cloudiness from suspended particles. These particles shield bacteria and viruses from UV exposure, allowing them to survive treatment and reach taps.
The formula for successful sterilization includes water clarity, flow rate, chamber dimensions, and lamp wattage. Change any factor, and the system fails to protect health. Contaminated water needs proper filtration systems to remove particles before UV treatment works.
NSF Certification Proves System Performance
NSF certification means systems actually perform as claimed. NSF International tests products through rigorous processes lasting years. Water systems must prove they remove stated contaminants under real-world conditions.
NSF 42 certification covers filtration and chemical removal, such as chlorine. NSF 55 Classes A and B certify UV sterilization effectiveness. NSF POE (Point of Entry) certification tests complete system structural integrity. These certifications cost substantial money but protect consumer health.
Making Smart Choices for Your Property
Choosing the right system starts with understanding actual water quality. Testing reveals specific contaminants needing removal. Properties on mains water need chlorine removal. Rural tank water requires sediment filtration and UV sterilization. Bore water might need additional treatment for minerals and chemical contaminants.
UV water systems excel at killing dangerous microorganisms but cannot remove chemicals. Carbon filters effectively remove chlorine but barely touch fluoride. Understanding these limitations prevents disappointment and wasted money on inadequate systems.