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What is UV treatment?

Ultra-violet (UV) treatment is the disinfection process of passing water by a special light source. Immersed in the water in a protective transparent sleeve, the special light source emits UV waves that can inactivate harmful biological substances.This method of treatment is growing in popularity because it does not necessarily require the addition of chemicals.

It is presumed in this document that the water you are using meets all health regulations and is known to be safe.

UV systems alone are neither intended to treat water that is visually contaminated nor intended to convert waste water to safe, microbiologically potable water.

If your drinking water comes from a private source, (such as a well), be sure to have your water tested periodically to ensure it safe to drink.

How does UV treatment work?

The ultra-violet rays, similar to the sun’s UV but stronger, alter the nucleic acid (DNA) of viruses, bacteria, molds or parasites, so that they cannot reproduce and are considered inactivated. UV treatment does not alter water chemically as nothing is added except energy. It should be noted that sterilized micro-organisms are not removed from the water, and UV treatment does not remove dirt and particles, metals such as lead or iron, or hard minerals such as calcium. Other devices are required to remove particles, metals and minerals, and information can be found in other About Your House documents in the water treatment series.

Do I need a UV system?

If your drinking water is municipally supplied or your regularly tested water source is safe, it is likely that you do not need a UV system for health purposes. If additional peace of mind for safe drinking water is your goal, UV may provide additional treatment to your water, but note that no one system can treat water 100 per cent, and that without proper maintenance it should not be considered 100 per cent reliable.

Is UV-treated water safe to drink?

UV-treated water is safe to drink — provided your source is known to be safe, or additional treatment devices are used. Prolonged storage of water after UV treatment is not recommended.

What sizes are UV systems?

UV systems can be small, portable devices that attach to a faucet and rest on the counter. They can be also be mounted under a counter. Both are called point-of-use devices.

Larger systems are available which are installed where the water supply enters the home, disinfecting the entire water supply. These systems are called point-of-entry systems. A small system can treat up to 4 L (0.8 gal.) per minute, while larger systems can treat 11 L (2.42 gal.) to 53 L (11.66 gal.) per minute. All types of systems require a 110-V outlet for operation.

What are the parts of a UV system?

A UV system is comprised of the following:

	UV light source called a "lamp" or "bulb". There are a variety of wattages for the lamp. Ensure your replacement bulb is the one the manufacturer recommends for that unit.
	Protective transparent housing for bulb — usually quartz.
	Power supply.
	A water chamber for the water to travel through for treatment.
	Filters for pre- and/or posttreatment.
	For larger systems, there may be a bulb replacement indicator light and/or alarm.

How much do UV units cost?

Costs vary from $300 for a basic self-installed unit to $700-$900 for a plumber-installed system—which includes a basic UV unit and labour. Costs can go up to $1,200 for a unit with more features. These include a flow-restrictor to make sure that the treatment capacity of the unit is not exceeded, a solenoid — a device that shuts off the water when the power is off — and an intensity meter to close down the system if the bulb is not producing strong enough UV rays.

If the system is combined with filters, there are additional costs for regular filter replacement. An annual filter/lamp replacement can be approximately $150. A lamp/ bulb alone may cost from $40 to $100.00 depending on the wattage of the bulb.

Electricity costs are another consideration, however, the system is similar to running a 60-W bulb.

There is no additional water cost for running a UV system, as the water treated is also available for consumption.

Who installs the UV unit?

Point-of-use systems can be installed by you; however, it’s important to know the condition of your water prior to use in the case you need some pre-filters.

With point-of-entry systems, there are a number of aspects that need to be considered when installing a unit.These include assessing the condition of the incoming water, the need to install some pipes and the need to properly disinfect the system. This work is probably best done by a plumber, water professional or mechanical contractor. If you are in a rural area and wish to install a system by yourself, contact a local plumbing supply store. In all cases, carefully read the manufacturer’s instructions and follow them to the letter.You may want to consult a professional if a larger system (one that uses filters) is required.

What are the installation considerations?

Water should be free of soil or sand particles (it should look clear and not cloudy). Such particles can block the UV rays and allow harmful particles to survive. Accordingly, a UV system normally has a fivemicron filter installed upstream from the UV unit. For surface water usage (as opposed to well water), a one-micron absolute filter should then be installed after the five-micron filter to remove cysts (small capsulelike sacs that enclose certain organisms). The UV unit is installed after these filters.

There are substances that can affect UV effectiveness such as water hardness, alkalinity, pH, and iron concentrations etc. Accordingly, water should be tested before installation to see if it will need additional treatment.This will assure proper UV disinfection. Contact a UV manufacturer or a water-testing laboratory to arrange a test.

How do I operate UV safely?

If your water is municipally treated, then simply follow the manufacturer’s instructions for operation and maintenance. The basics for a point-of-source (tap) model is to attach it to the faucet, plug the device into an electrical outlet and ensure the bulb is maintained by at least monthly cleaning, and replacing it annually.

When a UV unit is installed and the water source is not known to be safe, all pipes in the house should be disinfected with water mixed with unscented household bleach. It is recommended that you contact your local public health unit for the proper procedures. Any dead-end pipes should have taps placed on them to assure proper flushing and disinfection.This will ensure that any micro-organisms in the pipes are killed. If the electric power fails or the UV unit is off for any reason and water is used, contaminated water may enter your household system. In such cases where you suspect the water is unsafe you should boil water for two minutes before using the water for drinking and brushing teeth. When the electricity returns, the pipes should be flushed with chlorine bleach and water. Do not drink the water until the concentration of chlorine has been reduced.

How do I maintain a UV system?

UV units operate at a low cost. The bulb gradually loses its disinfecting capabilities over time. It should be changed by you at least once a year — even if it is still operating.The quartz sleeve surrounding the bulb must be kept clean in order for the unit to function safely. It should be examined once a month; and if it becomes cloudy, it should be cleaned.

Considerations

Other treatment devices may be required in addition to UV.

Prolonged storage of water using UV, as the sole method of treatment, is not recommended.

Certification

Health Canada recommends that all products that come into contact with drinking water be certified to the appropriate health-based performance standard developed by NSF International. In the case of Ultra-Violet Light units, it is recommended that they be certified as meeting standard NSF/ANSI 44. Components employed in conjunction with the UV system should also be certified to meet other applicable NSF/ANSI Standards. These standards have been designed to safeguard drinking water by helping to ensure material safety and performance of water softeners that come into contact with drinking water. In Canada, CSA International, NSF International, and Underwriters Laboratories have been accredited by the Standards Council of Canada to certify drinking water materials as meeting the above-mentioned standards.

These standards are widely accepted in North America , as they ensure the removal of specific contaminants, as well as the performance and mechanical integrity of the materials that come into contact with drinking water. Check the UV treatment unit's packaging or ask your dealer for a listing of the substances that the unit is certified to remove.

Where can I get more information?

You can check the Web site of NSF International at http://www.nsf.org for information about health-based performance standard related to drinking water treatment units. NSF also lists certified systems.

You can talk to various retailers and dealers to discuss different approaches to water treatment. A municipal water department or local utility may also be of assistance to you.