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Outback Water UV Systems - Frequently Asked Questions

Q.  What is the difference between an Ultraviolet system and a UV system?

A. Nothing, there is no difference, they are the same thing. UV is used as an abbreviation for the term Ultraviolet.

Q.  Does the UV process change the taste of my drinking water?

A. No, disinfection by UV is a physical process and not a chemical process. UV does not alter the water chemistry and will not affect the taste or odor of your water. UV only addresses the microbiological concerns.

Q.  Is a UV system expensive to operate and maintain?

A. When compared to other disinfection systems, the answer is no. As long as proper pre-treatment is maintained, an annual system check-up and lamp replacement is all that is required. As most UV systems are designed to be left on at all times, a typical household system will draw about the same energy requirements as a 40 watt light bulb!

Q.  I have never heard of UV as a treatment method before, is it new?

A. Although the term "UV" is most commonly associated with the potentially harmful exposure to the sun, UV has been in use for water treatment for over 100 years. UV was first used by the French in 1906 and has become commonplace in the residential, commercial and municipal markets over the past 20 years. Today, UV is likely the first form of treatment that one will look at when looking to address microbiological concerns in your drinking water.

Q.  I have read that UV is bad for me, is this true, or is this information incorrect?

 A. Sounds conflicting, but there is truth to this statement. Exposure to excessive amounts of sunlight can be harmful to your health. UV energy is actually broken up into three distinct wavelengths; UV-A, UV-B, and UV-C. Sunlight is comprised of all three UV rays however the most powerful UV-C rays are blocked out by the earth's ozone layer thereby protecting us on earth. Direct exposure to the sun should be carefully monitored in order to minimize the exposure risk. It is the UV-C portion that is used for the disinfection of drinking water and to a microorganism such as E-coli, UV-C is deadly. It is true that you don't want to expose your eyes or skin directly to the UV light in a treatment system, however the system is designed to prevent this from happening. In a properly designed UV system, there is absolutely no risk to the homeowner.

Q.  If I install a UV system, can you explain how it actually works?

A.  The UV process is a physical process as opposed to the addition of chlorine to the water to address microbiological issues which is a chemical process. This is important as UV addresses the microbiological issue without adding anything to the water or creating what is known as disinfection by-products (like trihalomethanes, which are proven to be carcinogenic). In simple terms, when a microbe is directly exposed to the UV light, the DNA (its fundamental building block) of the cell is damaged thus preventing replication. If a cell cannot reproduce, then the cell cannot cause infection.

Q.  Does UV work to eliminate micro biological organisms?

A.  UV does have an effect on all microorganisms to some effect. Whether it is bacteria, virus, algae, protozoan cysts, spores, mould, etc., exposure to UV light will harm the organism. Each individual organism requires a different level of exposure (know as UV Dose) in order to prevent cell replication. Some organisms, usually viruses, require extremely high doses of UV light in order to achieve disinfection. The important issue here is that one should ensure that the UV system they are purchasing delivers enough UV dose at the end of the lamp life to ensure adequate disinfection against a typical array of organisms found in drinking water.

Q.  Can UV effectively remove the bacteria E.coli from my drinking water?

A.  Escherichia coli or E.coli for short is a bacterium found in the lower intestine of warm blooded organisms. There are many strains of E.coli, some of which can be found in the water supply. Although E.coli has been blamed for many deaths (i.e. Walkerton in 2000), when exposed to ultraviolet light, at relatively a relatively low dose, UV is easily destroyed. Even the particularly virulent O157:H7 strain of E.coli has a 4-log (99.99%) reduction at a UV dose of 6 mJ/cm². It should be mentioned that all Outback UV systems deliver a UV dose in excess of 30 mJ/cm² at the end of the lamp life.

Q.  I have heard cysts are difficult to kill due to their hard outer surface. Can UV eliminate Cysts such as Cryptosporidium and Giardia lamblia from my water?

A.  No, although you may have read scientific articles from prominent researchers and from other UV companies, this information was based on old research studies. Original studies performed in the 1980's were based on excystation methods which lead to the belief that UV was ineffective against these protozoan cysts. In the early 2000's, it was proven by a host of independent research that UV was in fact extremely effective against both Cryptosporidium and Giarda lamblia at a UV dose of less than of 10 mJ/cm². The change was a result of testing methodology used in the earlier testing. This new information has opened the doors for UV to become a mainstream disinfection method.

Q.  I have heard of something called “log kills”. What does this mean and how does it apply to a UV system?

A.  The term log kill or more aptly log reduction, refers to the level of reduction that the ultraviolet energy has on a specific organisms in an logarithmic ratio. The term "Sanitation" is commonly referred to as a 2-log reduction which translates into a 50-99% reduction or a reduction of 1 out of 100. The term "Disinfection" is commonly referred to as a 4-log reduction which translates into a 99.99% reduction or a reduction of 1 out of 10,000. The term "Sterilization" is sometimes incorrectly associated with UV technology and represents a 6-log reduction which translates into a 99.9999% reduction or a reduction of 1 out of 1,000,000.

Q.  What does the term “Dose” mean in reference to UV systems? Why is it important?

A.  UV dose is the product of UV intensity (total UV energy per unit volume) and residence time (total time the water is in contact with the UV light), expressed by the equation D = I x T. Typically UV dose is expressed in the units mJ/cm² but can also be in microWsec/cm². The conversion between the two is, 1 mJ/cm² equals 1,000 microWsec/cm².

Q.  Can you tell me what level of “Dose” is right for my application?

A.  The right UV dose can be a difficult question and is directly dependant on the application. Many industrial applications are pathogen specific, meaning equipment and UV dose is chosen based on the dose requirements of a specific pathogen or group of pathogens. For the average home owner, the target pathogens typically require low UV dosages to be eradicated. As an example, E.coli, requires a UV dose of 6 mJ/cm² for a 4-log or 99.99% kill. Currently, three different UV dose levels exist in the market; 16, 30 and 40 mJ/cm². The 16 mJ/cm² dose is based on a US Public Health document produced in the 1960's. Typical waterborne pathogens will be eradicated at this UV dose, but with the emergence of some new viral contaminants and with the lack of a safety margin, this dose is typically used in instances to treat non-pathogenic or nuisance bacteria. Typical industry standards have long suggested a UV dose of 30 mJ/cm² at the end of lamp life. This dose allows for nearly double the original US Public Health dose and allows for a comfortable safety margin. The most recent UV dose suggested is that of NSF International (NSF) and the US EPA drinking water regulations, who suggest a UV dose of 40 mJ/cm². This dose is the direct result of the introduction of certain emerging pathogens (specifically rotavirus) that was found to require a dose of 36 mJ/cm² for eradication. Outback publishes system flow rates at all three dose levels in their literature and allows the customer to make their own educated decision on what is best for their requirements.

Q.  We get our household water from a nearby lake. The report we get on the water quality of the lake says it is fine. Why would I need to still disinfectthe water coming into my home with a UV system?

A.  Even though you may have received a "negative" test result for bacteriological contaminants, it is important to realize that this is a single test and a single point-in-time. If you are drawing water from a non-municipal source, or a source that is of unknown quality, it is imperative that you follow some form of disinfection prior to the consumption of any water from that source. The reason is that there can be season fluctuations in the quality of the water and one single test, does not guarantee a safe result for 365 days of the year. If you live near a local beach that happens to be closed periodically throughout the summer months you will easily understand the reasoning. Bottom line is that if the source is unprotected, you are the only one who can ensure the safety of that source and it is your responsibility to do so.

Q.  Once, the UV system is installed on my incoming water supply, do I need to continue testing for biological contamination?

A.  Yes, although you have taken the right step to install a UV system to protect you and your family from bacteriological contaminants, it is important to continue to test your water to ensure everything is working as intended. Having your water tested every six months is simply an additional peace of mind that takes very little time.

Q.  I live in the city, is there any reason to install a UV system on my incoming water supply?

A.   The answer to this question depends on ones level of confidence. Although most municipalities do provide bacteriological safe water to their clients, and this is closely monitored by most provincial, state, or other regulators, there have been numerous instances around the globe where water has been provided from the municipality that may not be safe. In these cases, the municipality will inform their clients that the water is in fact unsafe for consumption andwill suggest alternate means. In these cases the UV system installed in your home acts as "the insurance for your water supply". The need for this level of insurance is up to you, but considering the fact that water is the number one key to life, it seems to be a very inexpensive way to offer the security that you may be looking for, for you and your family.

Q.  What is a Boil Water Advisory and how does it affect me?

A.  A Boil Water Advisory (BWA) will be issued by your municipal water provider if the municipal water being provided to your home or business is deemed to be unfit for human consumption. This may be the result of a number of circumstances, however the municipality is informing their customers that at this point-in-time, the water is not safe for drinking, unless treated by some other method such as physically boiling the water for a minimum of 1 minute at a rapid boil. Depending on the exact nature of the BWA, other precautions may need to be taking such as avoiding baths or showers (especially in water ingestion is possible). The municipality will advise when the BWA is over and how to ensure your home's water supply is made safe. For an example of some of the procedures surrounding a BWA, please click here.

Q.  Do I need to hire a plumber to install the UV system or can I install it myself?

A.  If local state or provincial regulations allow, the installation of a residential UV system can easily be done by the competent handyman. The typical installation involves cutting into the cold water supply and installing the UV with unions and appropriate fittings. Once installed, the unit is plugged into a separate GFCI plug. Please refer to one of the installation manuals found within this site for more detailed installation instructions.

Q.  What is the difference between a POU (point of use) and POE (point of entry) system?

A.  In deciding whether a point-of-use (POU) or point-of-entry (POE) unit should be installed one should determine the potential locations (taps) within the home where one could consume water. If there is only one tap in a small cottage or apartment, then one might consider a smaller POU system to treat a single location. The same would be true if you were looking to add either pre or post treatment to a residential RO system. Typically if there is more than one tap (a kitchen and bathroom) in a home, a POE system would be installed in a main cold water location before any cold water lines split to send water to different locations in the home. The slight increase in price for a larger system and the POE installation ensures that all locations within the home are treated

Q.  I do not drink the water I my bathroom, do I need to install a system that treats the bathroom faucets?

A.  You may decide not to drink form the bathroom tap, but what if you have guests, or someone who visits your home and assumes the bathroom water is okay for consumption. Where do you brush your teeth? If it is in the bathroom, then treating potential contaminated water in the bathroom is imperative. You don't have to swallow the water to become infected with a potentially harmful organism. Consider the brushing action against sore or bleeding gums and one can easily see the consequences. It is because of this that it is highly recommended to install a whole home POE system whenever possible.

Q.  Does UV need any type of pre-filtration?

A.  Yes, UV works extremely well at addressing the microbiological issues, but can be greatly impeded by the presence of other water chemistry issues. The main concerns for UV are that of water hardness, tannins, turbidity, iron, manganese and UV transmittance. As hard water can physically stain the quartz sleeve component of a UV, it is recommended that the water hardness be less than 7 gpg. Tannins should be less than 0.1 ppm or 0.1 mg/l. Turbidity should be less than 1 NTU. Iron should be less than 0.3 ppm (0.3 mg/l) and manganese should be less than 0.05 ppm (0.05 mg/l). Although UV can be used on waters with a UV transmittance of less than 75%, for residential applications at the systems rated flow, it is recommended that UVT levels be greater than 75%. All these issued can be addressed by other water treatment equipment such as filters and water softeners (many of which can be found on this site). The minimum pre-treatment that is recommended is the installation of a 5 micron pre-filter in front of the UV system. Again, these systems can be found in the filtration section of this site.

Q.  What are Tannins? Why do I need to remove them?

A.  Tannins, also known as tannic acid or Humic acid is a nuisance contaminant that affects the functionality of a UV system. Tannin in drinking water usually comes from composting organic matter (i.e. leaves, vegetable matter, etc.) and is most likely to appear in springs and wells bordering swampy areas or near coniferous tress. Tannins color the water with a yellow hue and can cause staining on fixtures and affect the aesthetic quality of drinks. In relation to UV tannins interfere with the UV's ability to penetrate into the water due to the tannins absorption capabilities. For a UV system to function properly, tannins must be removed from the water via a special macro-porous Type 1 anion exchange resin, or by chlorination.

Q.  What does UVT mean? Why is it important?

A.  UV transmittance or simply UVT describes the measurement of a fluids ability to transmit UV light. Typically, municipal water supplies have UVT levels of greater than 95%, whereas deep water wells typically have UVT levels around 85%. The UVT of surface waters can vary greatly depending on the source and surrounding geography. UVT can be easily tested with a spectrophotometer which most laboratories or UV manufacturers have. Waters with lower UVT's will require more UV energy to deliver a similar UV dose than waters with a higher UVT. Outback systems are tested at a 95% UVT level and their rated flow is based on the waters having a minimum UVT level of 95%. If your water has a lower UVT, the system will deliver a lower UVT dose, or the flow rate through the system will need to be decreased to achieve the same UV dose. Dosage curves are available for all Outback systems to aid in this selection. As a precaution, it is recommended that all water treated by a UV system have a minimum UVT level of 75%.

Q.  I have a pretty good idea why you need to use pre-filtration ahead of a UV system, but is there a way exactly what type of pre-filtration my specific location may require?

A.  Before the installation of a UV system, your water should be tested to determine the basic water chemistry. The minimum tests should include hardness, tannins, turbidity, iron, manganese and UV transmittance. These tests can be typically performed by the many testing laboratories that are in existence.

Q.  Once I have made the decision to purchase and install a point of entry UV system, can you tell me the best location or exactly where to install it?

A.  The UV system should be the last piece of treatment equipment. Water softeners, filters, etc. should all be installed prior to the UV system. All the treatment equipment should be installed on the main cold water line feeding the house and before any branch lines including those feeding the hot water heater.

Q.  I have learned that UV does not have any residual disinfection like chlorine, so how do I get rid of the bacteria that may currently reside in my plumbing system?

A.  Before the water is consumed after the installation of a UV system, the entire distribution system (piping) must be disinfected with chlorine to ensure that the UV system delivers its disinfected water through a disinfected distribution system. This can be easily done by adding household bleach, or similar disinfectant, in the pre-filter housing (that must be installed with each UV system). First, remove he cartridge and then fill the filter sump with the bleach. Then go to each tap in the house and run water until you smell the bleach and then turn off the tap. Make sure you flush the toilets, run water into the dishwasher and washing machine as well as any showers. Finally run water through any outside hose bibs and any other location that has water. Leave the entire system for a minimum of 30 minutes and then flush the system to remove the bleach. Once this is complete, the water will be ready for consumption. Throughout this process, do not shut off the UV system (please note that if you have a UV system that contains a UV monitor, the alarm may sound during this process as the bleach interferes with the proper reading of the UV monitoring system).

Q.  I have a second home that I only occasionally use, should I turn the system off when I am not there to save energy?

A.  You can turn the system off if you are away for extended periods of time, however you must remember that if you turn the system off, you will need to disinfect the distribution system each time you restart the UV system as there is a possibility that the bacteria that may exist in the water can migrate and replicate through the UV system when the system is off and could contaminate the distribution system after the UV system. As UV has no residual, there will be no way to clean up the down bound distribution system besides disinfecting the entire system with bleach. Considering this and the fact that a typical household UV system consumes about as much power as a 40 watt light bulb, many people elect to leave the UV system on, even when they are away for an extended period of time.

Q.  I have a vacation property that is not used in the winter. Do I need to worry about the UV freezing?

A.  Yes, as the UV is part of your regular water system, you will need to properly drain the water from the UV reactor the same as you would with any other fixture in your vacation property.

Q.  Some UV systems turn the lamp off and on every time water is drawn, should the Outback system be turned on and off?

A.  There are some countertop POU systems that are specifically designed to be turned on and off every time water is drawn from the faucet. These systems are specifically engineering for this function. Outback’s systems should not be turned off unless it is for an extended period of time. The systems are designed for continuous disinfection and not for on-off cycling as this can severely reduce the overall life of the UV lamp.

Q.  What makes the OutbackWater UV lamps so special?

A.  The UV lamp acts as the heart of the UV system and Outback uses the best available lamp technology. All our lamps are manufactured with a proprietary internal coating providing consistent UV output over the entire life of the lamp. Ceramic lamp bases are used for thermal efficiency and structural integrity. The lamps bases are color coded and base marked for easy identification and maximum output.

Q.  How long do the OutbackWater UV lamps last?

A.  UV lamps do age and do so in the same manner as a standard fluorescent lamp. Outback’s low pressure (LP) and low pressure, high-output (LP-HO) lamps have a rated service life of 9,000 hours or approximately one year of continuous use.Outback’s amalgam lamps used in our commercial/industrial and municipal lines have a rated service life of 12,000 hours. At OutbackWater, we guarantee all our lamps to have a minimum life of 1 year. It should be noted that illumination does not necessarily mean disinfection. The bluish glow given off by a low pressure mercury vapor lamp is actually the glow of the mercury vapor. The actual UV energy providing the disinfection is invisible to the naked eye. A lamp that is still emitting the bluish light does not mean it is providing enough, or any, UV energy. This is why the lamps should be changed at the time as recommended by the manufacturer. On OutbackWater UV systems there is an integral lamp change reminder built to warn the user when it is time to change the UV lamp.

Q.  Is it recommended to install a bypass loop to allow for water flow in the case the UV is off line, for example due to service?

A.  Yes, the installation of a bypass valve is highly recommended in order to allow water flow in case the UV system has to be removed for some reason. Please note that notification should be provided, and posted, at each location where water is drawn to ensure that no one accidently consumes contaminated water. When the system is put back online, a full chemical disinfection must be made on the distribution system.

Q.  Will my incoming water pressure be affected with the installation of a UV system?

A.  No, all Outback systems are engineered to achieve a minimal pressure drop for the specific flow rates of each individual model. Typically pressure drops are less than 3 psi.

Q.  How do I clean the UV system's Quartz sleeve?

A.  Depending on the influent water quality, the quartz sleeves may need to be removed and physically cleaned. On Outback systems, there is no need to drain the reactors as is the need in competitive systems. The sleeve is easily removed by remove the top retaining nut and carefully sliding out the quartz sleeve. You can use a commercially available scale cleaner such as Lime-Away or CLR can be used to clean the sleeve. When cleaning the sleeve wear gloves to ensure that no fingerprints are left on the sleeve and ensure that the sleeves are thoroughly rinsed with clean water to remove any of the cleaning agents before reassembling.

Q.  How do I know my UV system is working?

A.  All Outback systems come with a lamp monitoring device. If the lamp is not illuminated an audible alarm will sound. Please note that this alarm deals with a "lamp-on" condition only. Lamps that are not changed out on an annual basis or systems that do not follow the pre-treatment protocols may result in a false sense of security. The only way to ensure the system is working properly is to obtain a bacteriological test.

Q.  How much space do I need for a typical household installation?

A.  As the UV lamps are removed through the axial length of the reactor, a space equal to twice the length of the reactor is needed. In the case of a typical 38 lpm (10 gpm) reactor, this would account for a space requirement of approximately 165 cm (65").

Q.  Are the UV systems designed to be installed vertically or horizontally?

A.  As the UV unit is a self contained pressurized vessel, the orientation of the reactor chamber is not a concern from a disinfection standpoint, however for ease of installation and service, it is recommended to install the system in a vertical orientation with the retaining lamp (and lamp removal) located at the top.

Q.  If UV systems are rated for a specific flow rate, is there a way I can make sure that I do not exceed that rate?

A.  To be absolutely sure that the UV system does not exceed the manufacturers rated flow, the installation of a flow restrictor is recommended. These flow restrictors are designed with a variable orifice that fluctuates with variations in water pressure. The maximum flow is controlled by the restrictor which is ideally installed on the outlet port of the UV reactor. Flow restrictors can be purchased through your looking plumbing supply distributor.

Q.  Can I install a UV system outside?

A.  No, these systems are designed to be installed indoors and away from the elements. The manufacturer's warranty will not apply if the units are installed in an outside environment, or if they are exposed to spraying or splashing water.

Q.  I have been told my system must be NSF approved, is this true?

A.  This does depend on where you live and on what type of application. You should check with your local government and should follow their recommendation. It is important to remember that NSF International is a voluntary tested organization and is just one of the many testing organizations that exist.

Q.  What if I need parts for my system, where can I get them?

A.  To obtain replacement components for your UV system, you should contact the local retailer where you originally purchased the UV system. They will be able to supply you with parts, or order them for you. If that option is unavailable to you, replacement parts can be obtained directly from the factory. Contact us for additional information.

Q.  The water coming out of my cold water tap is warm, why is that?

A.  The UV system is installed on the cold water line in your home. The disinfection occurs by the ultraviolet lamp contained inside the stainless steel reactor chamber. Although the UV energy itself gives off no heat, the low pressure mercury vapor lamp ("light bulb") does emit energy in the form of heat. It is this energy that can in some cases warm the water up. This may be a problem when there is a long period of dormant (no flow) activities such as at night. The problem may be compounded if the UV system is located close to a tap. To remedy this situation, and recommend by most municipalities, run the water for a few seconds before filling a glass. This will not only rinse the lines with any stagnant water, but will also flush the warm water from the system. Most people view this feature as an additional way to know that your system is still on an operating as in most cases the UV is installed somewhere out of the way and away from normal view.

Q.  How do I dispose of my old UV lamp?

A.  The UV lamp should be disposed in accordance with your local regulations. The lamps should be disposed in the same fashion as any other fluorescent light fixture that may be in your home or office. At Outback, we strongly encourage recycling...for more information, please visit www.recycle.org.