Frequently asked question for Whole House UV Systems

UV Disinfection System
About UV: What is ultraviolet light?

Ultraviolet light exists at the invisible, violet end of the light spectrum. Although we can't see UV light, we are exposed to a small amount every time we walk out into sunlight. The water treatment industry uses special lamps that emit UV light of a particular wavelength in order to disinfect water.

Functionality: How does UV work?

The germicidal energy of ultraviolet light destroys illness-causing microorganisms by attacking their genetic core (DNA). This powerful dose of UV light (wavelength of 253.7 nanometers) eliminates their ability to reproduce, and the organisms simply die. Disinfecting your water with ultraviolet light is exceptionally simple, effective and environmentally safe: our systems destroy 99.99% of harmful microorganisms without adding chemicals or changing your water's taste or odor. It is well proven, and it is the way of the future for water disinfection.

Whole House UV Disinfection


Who Needs UV: When do you need a Whole House UV light?

Whole House UV Systems are an effective means of water disinfection for residential point of entry (POE) use. UV water sterilizers are designed to specifically kill 99.99% of harmful microorganisms such as bacteria and viruses in untreated water (well water or private well systems). Whole House UV systems are highly recommended to homeowners who may suspect E.coli, cryptosporidium, giardia or any other types of bacteria and viruses in the water. Ultraviolet (UV) technology is more effective than chemicals in destroying certain waterborne contaminants and is safe and chemical free. For the most complete and safest purified drinking water, pair your UV system with a point of use (POU) reverse osmosis drinking water system for bottled quality drinking water.

Chlorine Concern: Why is disinfecting your water with chlorine bad for you?

Many people object to the taste and smell of chlorinated water. But a greater concern is chlorine's ability to react with certain compounds that may be present in the water supply, to create by-products that have been linked to cancer (such as trihalomethanes, or THM's). By comparison, UV light is a natural process and does not produce harmful chemicals in drinking water. It's a safe, effective, and environmentally friendly disinfection method that is widely used for residential and industrial applications around the world.

Pre-Treatment: Is pre-treatment of my water recommended for a UV system to work?

A 5-micron sediment filter should be installed upstream of any UV system so as to eliminate any particles large enough to block the UV light. Additional activated carbon filter pre-treatment can be added after the sediment filter in order to remove some invisible organic compounds that may absorb the UV energy and reduces the efficiency of the system. The UV system should always be installed downstream of any other water treatment equipment. Ultimately, the quality of your water will determine if additional pre-treatment is required.

  • Chemicals such as iron and calcium carbonate can form deposits on the UV lamp's protective sleeve, reducing the light that can penetrate the water. Water softeners and iron removal systems are sometimes required.
  • Chemicals such as iron, tannins and humic acid are able to absorb UV light and thus reduce the amount available for disinfection.

Energy Consumption: Does a UV light consume a lot of energy?

No, a UV system able to treat the water for a typical house will consume about the same amount of energy as a 40 or 80-watt light bulb depending on the model. UV is a cost-effective, natural way to improve water quality.

Choosing a System: How do I know what size UV unit I need?

If you draw from a private water supply, it is recommended that you treat the water for your entire home. To assure your highest satisfaction, please choose the right size (gpm) of UV system that matches your household peak demand flow rate. This is simply a measure of how much water can flow through your main water line if all the water outlets were opened at once.

Typically, a North American house might have a maximum flow rate of 7 GPM (26 LPM), while a larger home might reach 15 GPM (56 LPM) or more. You may also determine the flow rate you need based on the number of bathrooms in your home.

Number of Bathrooms in Your Home Flow Rates (in gpm)
1 Bathroom 5
2 Bathroom 8.5
3 Bathroom 12
4 Bathroom 15.5
5 Bathroom 19
6 Bathroom 22.5

UV Transmittance: What is UV transmittance (UVT)?

UV transmittance (UVT) measures water's ability to transmit UV light. The majority of deep wells have a UVT of about 85% or greater and most of municipal water supply have about 95% UVT. Surface water such as lakes, streams, ponds and springs may have about 75% UVT. Water with a lower UVT will require a larger UV system to deliver the disinfection performance required. Therefore, we recommend pre-treating water that has less than 75% UVT as it will affect the dosage* your UV system is capable of producing.

*Dosage: it is the intensity of UV light that is able to penetrate each liter of water measured in Millijoules per liter (m/J) that passes through the UV chamber.

UV Lamp Life: How often should I change the UV lamp?

The amount of UV light created by the lamp decreases over time, like light bulbs, UV lamps will dim with age and eventually burn out. So, it is essential to replace the UV lamp every 12 months. These whole house UV units are designed to generate the necessary UV light intensity for only one year of continuous use. The lamp will continue to burn long after, but it will not generate an adequate amount of UV light.

Note: The UV system is designed to operate continuously and should not be shut off for short periods of time, such as over a period of less than three weeks.

Taste: Will UV change the taste of my water?

No, UV will not change the taste or odor of the water. It does not add anything to the water and simply provides safe and reliable disinfection for your entire home. If your water contains hydrogen sulphide (rotten egg smell), the UV treatment may slightly improve the smell of the water.

Performance Test: How do I know if the system is working?

Systems are equipped with both audible and visual alarm signals to notify the homeowner if their system is not functioning properly. It is important to clean your lamp regularly and replace the UV lamp annually to ensure maximum performance.

Installation: Where should I install the whole house UV light?

This whole house UV unit works in tandem with a pre-treatment system that prepares your water for UV disinfection. The UV system must be installed after all water treatment equipment and we suggest installing the unit indoors at room temperature only.

System On/Off: Should I turn off the UV light when I am not using water?

No. The whole house UV light is designed to operate continuously. If the system is turned off, it may be possible for bacteria and viruses to travel through the water chamber and contaminate the distribution lines past the UV system. In addition, frequently starting and stopping the lamp and ballast may reduce its life span.

Maintenance: What kind of maintenance is required for the whole house UV system?

Every whole house UV system contains a UV sleeve to protect the UV light bulb. Overtime, minerals in the water may slowly form a coating on the sleeve during normal operation. This coating must be removed from the sleeve because it reduces the amount of UV light reaching the water, thereby reducing purification performance. Therefore, it is recommended to use scale removers such as Lime Away™ or CLR™, with soft, lint-free, and chemical-free cloth to remove any coatings adhering to the sleeve. Depending on the quality of the process water, we suggest you clean the sleeve regularly, about 3-4 times a year.

Cleaning the lamp is not necessary because the lamp itself is protected by the sleeve. The need to clean the sleeve will be indicated by the UV alarm on the UV-WHS-14-PLUS, UV-WHS-28, UV-WHS-47 models. If the process water entering the UV system is sufficiently filtered, then the cleaning requirement would be less frequent. If you have the whole house sediment filter upgrade option, the filter should be replaced every 6-8 months depending on your water quality.