How to Get the Best Results from a UV Water Sterilizer

Getting the best results from your UV water sterilizer

Before purchasing a UV light water filter system, make sure the unit is sized correctly for your application and make sure you have the right prefiltration in place for UV disinfection to work properly.

How to Correctly Size the UV Sterilizer System

First, it’s important to know that the UV water filtration system you install has right flow rates for your household. The flow rate of the water is a measurement to determine the system size and ultraviolet water treatment units are sized by how many gallons per minute (gpm) the system can effectively treat.

If you’re installing a UV drinking water system under your kitchen sink, then a typical flow rate for this type of UV system is 1-9 gallons per minute, such as the Viqua VH200).

But if you’re considering a whole-house UV water sterilizer system, a typical system can treat 8-10 gallons of water per minute. The system’s flow rate impacts the amount of UV light treating your household water, and you’ll want a system that can treat the minimum dosage rating to protect your household.

For proper protection from 99.99% of waterborne microbiological contaminants, most whole-house UV systems will have a UV dosage rating of 30 millijoules of UV per square centimeter (mj/cm2). This dosage will protect against a wide array of dangerous microbes.

Suggested Reading: UV Buyer's Guide

effective UV light filtration provides clean water for your family

Expert Tip:
Number of Bathrooms in Home Can Determine Needed Flow Rate for UV Light Disinfection System

For whole-home applications, a simple way to determine what size UV system is needed, is by assessing the number of bathrooms in the house. Here's a flowrate guide for whole-home UV sterilizers.

6 gallons per minute flow rate.
If you have one bathroom in your home, you'll need a UV water sterilizer with at least 6 gpm flow rate, such as the Luminor Blackcomb 4.1 LB4-061 UV system.

9 gallons per minute flow rate.
If you have two bathrooms in your home, you'll need a UV water treatment system with at least 9 gpm flow rate, such as the Viqua VH200 UV System.

12 gallons per minute flow rate.
If you have three bathrooms in your home, you'll need a UV water system with at least 12 gpm flow rate, such as the Viqua 650694-R D4 UV System.

15 gallons per minute flow rate.
If you have four bathrooms in your home, you'll need a UV water sterilizer with at least 15 gpm flow rate, such as the Luminor Blackcomb 6.1 LB6-151 UV System with Sensor.

18 gallons per minute flow rate.
If you have five bathrooms in your home, you'll need a UV water system with at least 18 gpm flow rate, such as the Viqua VH410 UV System.

Flow rates for commercial applications are determined with a variety of other factors. Please contact us for more information.

If the system you install is under flow-rate capacity, your home’s water may not be treated effectively by the system’s UV lights. For this reason, we encourage customers to “oversize” the UV system flow rate capacity to ensure it can properly treat the water. This way, if multiple appliances and showers are running at the same time, your system can handle all incoming water needs.

We offer many different UV systems for each flow rate category above. If you’d like recommendations on which system is right for you, feel free to give us a call.

NOTE: Flow rates for products with NSF “Class A” certification are rated at 40 mJ/cm2. NSF “Class A” certified systems are typically only used for specific commercial applications.

Do I Need Other Filtration with My UV System?

Yes, we generally recommend that water go through a sediment pre-filter before entering the UV light chamber. This makes sure that your water is clear enough for effective UV disinfection. If your water is cloudy, UV light may not be able to contact and destroy dangerous microbes in the water.

If you have “hard water” (water that is high in magnesium and calcium), you’ll most likely want to install a water softener in front of the UV water treatment system. If left untreated, hard water can cause scale build up on the UV lamp, thus decreasing the UV process effectiveness.

After pretreatment has been installed, the incoming water to the UV system meet the following parameters:

    • Turbidity < 1 NTU
    • Manganese < 0.05 parts per million
    • Hardness < 7 grains per gallon
    • Iron < 0.3 parts per million
    • Tannins < 0.1 parts per million
    • UV Transmittance > 75%

If your water does not meet the above parameters before entering the UV chamber, then pre-treatment equipment may be necessary. Again, pretreatment is important because high levels of sediment, iron and water hardness may degrade the performance of your UV system and not allow it to properly treat the water.

If you’re on a private well, it’s especially important to know what contaminants are in your water. Because private well water is not regulated by municipalities, we highly recommend that you find a water testing lab that can provide you with a water analysis that includes testing for E.coli bacteria, viruses, and other contaminants. 

Plumbing Considerations When Installing a UV Water Filter

Plumbing is also an important consideration when selecting a whole-house UV water disinfection system. Make sure if your household has 1-inch plumbing that you install a system with 1-inch plumbing connections and not 3/4-inch.

Options Available with Your UV Water Treatment System

One last consideration when selecting a UV system is the options available for system operation.

A countdown timer indicating when the UV lamp needs to be replaced comes standard on most UV systems. But you may wish to upgrade to a system with a touch-screen display or a system with LED lights that indicate the status of various system components.

Top-Selling UV Water Filter Systems

Viqua VIQUA VH410-F20 Model 18 GPM Combo UV System VH410-F20-
  • Economical UV Treatment

  • Lamp Life LED Display

  • 9 gpm UV for Small Home

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Viqua VIQUA D4 Model 12 GPM UV System - 650694-R 650694-R-
  • Color LCD Screen

  • Lamp Replacement Timer

  • 12 gpm Monitored UV
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  • Includes 5-Mic Pre-Filter

  • Lamp Life LED Display

  • 9 GPM Water Treatment

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