Do You Install A UV Filter Horizontal Or Vertical?

You can keep your water free from impurities with a UV filter. When you install this device, you should position it correctly because it's critical for the functioning of the UV filter. We've researched and found simple installation instructions.

Refer to the UV filter installation manual to see if it allows a horizontal or vertical position. Although, most have vertical installation for easy access to electrical connections and a neat appearance. You can install it horizontally if the manufacturer recommends it.

The manufacturers may require certain filter system components for a specific filter direction. While others only recommend one direction because their filters will not work well in an alternative direction. Continue reading to learn how you should install a UV filter!

collaged-photos-of-a-horizontal-or-vertical-uv-filters-rev, Do You Install A UV Filter Horizontal Or Vertical?

What Is The Best Way To Install A UV Filter — Vertical Or Horizontal?

A UV filter helps disinfect water flowing into your home. Water UV systems can destroy 99.99% of harmful organisms in the water.

The UV rays remove bacteria and other pathogens without using toxic chemicals. Hence, adding a UV filter is a good investment for your home.

Besides consumption, UV filters are also for aquariums, fish tanks, ponds, and similar water facilities. Regardless of where you put the filter, its primary purpose is water treatment.

You can benefit from the filter if the installation is correct. If the position is incorrect, you might damage the filtering equipment.

First, when installing the filter, consider its positioning. The position of the UV filter depends on the manufacturer's instructions. You can install the filter vertically or horizontally as long as the product instructions permit.

Here are the distinctions between the two positions below:


Most manufacturers recommend the installation of UV filters vertically.

A vertically-installed filter creates a neat and expert look. There are mounting wall brackets you can use to achieve the correct positioning.

There will be free air circulation and optimal cooling around the ballast housing. The vertical installation of the UV filter is best for efficiently servicing the UV bulb/lamp on top. Electrical connections are also easy to access.

There are UV filter brands that only allow vertical installation. Manufacturers do not allow their filters to be mounted sideways. They recommend vertical installation to balance the quartz sleeve.

Moreover, there can be state codes to follow for UV filter installation.

According to the State of Connecticut, the water outlet should be on top if you install the filter vertically. By doing so, water can fill the chamber, and there will be more exposure to the UV lamp.

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Water filtering system close-up view

In contrast, some manufacturers are allowing horizontal installation. They have specific UV filter versions that should be horizontal. One design is a wiper; the horizontal installation keeps the wiper seal wet.

You can install it horizontally with limited free space under your kitchen sink. Other manufacturers have horizontal-oriented UV filters traditionally. In this case, the water filtering system accommodates large volumes of water for whole-house applications.

When installed horizontally, state codes require the water outlet's direction to be upward.

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Does It Matter Which Way Water Flows Through A UV Filter?


It will not matter if the manufacturer allows installing it either way.

If there is a specific direction that the manufacturer requires, you must follow it. A UV filter kit can include a pre-filter that will take up space, so you must evaluate your options.

Consider the following when installing the UV filter:

  • Proximity to an electrical outlet
  • The direction of water in the supply line
  • A plumbing diagram
  • Space requirements

The UV filter does not affect the rate of water flow. Yet, the position can affect the exposure of water to the filter. So, you must follow the correct positioning based on your needs or the manufacturer's instructions.

For large and complicated water filtering systems, let a certified plumber check the layout of the water supply.

What Are The Advantages Of UV Water Filters?

You might wonder why you need to follow the correct direction to install the UV filter. Listed below are the advantages why you need one:

  • Cost-effective
  • Chemical-free water purification
  • Water maintains taste
  • Easy installation
  • Low maintenance
  • Does not produce waste
  • Use less energy
  • Environment-friendly
  • Treats bacteria and viruses

Although you can have purified water, adding a UV filter is not enough. A UV filter needs a device for reverse osmosis to eliminate chlorine, heavy metals, and VOCs from water.

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Is It Possible To Use A UV Filter For Your Whole Home?

Yes, it is possible to use a UV filter for the whole house. UV filter systems can be for point-of-use, for example, the kitchen tap.

Alternatively, they can be at the point of entry, meaning it's for the whole house. The whole-house application will disinfect water for bathing, cleaning, and washing.

In the past, only municipal water systems in urban cities used UV filters to treat the water. Now, there are available UV filters for residential applications.

Adding a UV filter where water comes into your home is a first-line defense against contaminated water. It is generally attached to the main home's water line.

The filter can kill harmful bacteria, such as e.coli and coliform, which are detrimental to humans.

You should also have a sediment filter when installing a point-of-entry UV filter. Plus, there are filters with UV sensors that are NSF certified to monitor the intensity of UV light.

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Should You Install A UV Filter Before Or After Water Softener?

You should install the UV filter after the water softener. Water that passes through the UV filter should be clear with low levels of minerals. If the water hardness is around five to ten grains per gallon, it needs a water softener.

Water softeners only reduce water hardness and do not remove microorganisms and contaminants. The softeners may not be enough for the whole house water treatment.

Hence, UV filters can help safeguard the water from impurities.

The UV transmission level should be low so that the UV rays penetrate the water. A UVT of near or above 90% allows more UV rays to pass through.

Your UV filter can disinfect better with the correct levels of UVT after applying the water softener.

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Do You Fit The UV Light Before Or After Filter?


It is best to install the UV light after the filter. The UV water treatment assembly has a built-in UV light, generally after the filter. The UV filter works more efficiently if there are no more debris and other big particles in the water.

In addition, installing the filter before the UV light protects the quartz sleeve from damage. The downside of adding UV light after the filter is the clumping and setting of dead microorganisms at the bottom.

You might need another device to remove the filtered substances. If you want to avoid the extra cleaning effort, add the UV light before the filter.

How Much Will It Cost To Install A UV Filter?

Close-up image of unrecognisable person doing a maintenance service on a household filtration

You might spend around $100-$500 to install a point-of-entry UV filter by a professional. If the plumbing system in your house is complex, the rate can go high to $2,000.

Installing point-of-entry filters is cheaper, which will cost $300 at most.

Prices may depend on the installation's location, expertise, and complexity. You can save money if you have the skills to install the UV filter. If not, it is best to let a professional do the job.

To Finish


You can install a UV filter vertically or horizontally. Check first if the manufacturer allows installing on one position or either way.

Vertical positioning is possible with wall brackets that create a neat look. Installing the filter in a horizontal position is suitable for whole-house applications.

Decide how you position the UV filter by considering the space, water line direction, and closeness to electrical components. Besides, you should add the UV filter after the water softener.

With the correct position of the UV filter, you can have purified and safe water for your home.

Made it to the end? Check out these helpful related articles below!

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