Osmio PRO III XL Whole House Water Filter System
A premium whole house water filtration system designed to improve the water quality throughout your home, including taps, showers, baths, appliances and general household use.
The Osmio PRO III XL Ultimate Whole House Water Filter System is one of our leading whole home filtration systems for customers who want filtered water from every tap without relying on filter jugs or separate point of use filters in every room.
This system is designed to reduce chlorine, unpleasant taste, odour, selected heavy metals, hormones, pesticides, organic material, fluoride and bacteria including E. coli and Pseudomonas. It is especially suited to homes where water quality, shower water, bathing water and general household water feel just as important as drinking water.
For a full explanation of the different types of whole house water filters available, see our Whole House Water Filter Types Complete Comparison Guide.
Why Choose The Osmio PRO III XL?
Whole Home Filtration
Filters water at the main incoming supply, helping improve the water used across taps, showers, baths and household appliances.
Three Stage System
Uses active ceramics, carbon block filtration and GAC with KDF media for broader water treatment than a basic single stage housing.
No Backwashing Required
Unlike some large whole house systems, there is no routine backwashing cycle. Replace the cartridges when they reach the end of their service life.
High Flow Performance
Designed for pipework up to 1 inch and performs best at flow rates up to 70 LPM, making it suitable for many medium and larger homes.
Is The Osmio PRO III XL Right For Your Home?
The Osmio PRO III XL is best suited to households that want a premium whole house filter rather than a small under sink or countertop drinking water filter. It is designed for customers who want cleaner water throughout the property, including bathroom water, shower water and general household water.
This system is a strong option if your main concerns are chlorine smell, chemical taste, unpleasant odours, sediment, selected heavy metals, pesticides, hormones, bacteria and overall water quality. It is also useful for customers who dislike the smell of chlorinated shower water or want to reduce exposure to common contaminants across the whole home.
It is not the right choice if your only concern is limescale. Whole house water filters and water softeners solve different problems. If you have hard water marks, scale around taps, kettle scale or appliance scale, you should also view our Water Softeners collection.
Best Suited For
- Homes wanting filtered water from every tap
- Families concerned about chlorine, taste and odour
- Customers wanting improved shower and bath water
- Medium to larger homes with suitable pressure and flow
- Households looking for a low maintenance cartridge based whole house system
- Properties where a single under sink filter would not be enough
How Does It Compare To Other Whole House Water Filters?
Many whole house filters use a single cartridge, usually for sediment or carbon based chlorine reduction. These can be useful, but they often have a narrower purpose. The Osmio PRO III XL uses three separate housings and three different filter stages, giving it a broader filtration profile.
Compared with a basic carbon only whole house filter, this system is designed to target a wider range of water quality issues. Compared with a sediment only filter, it does far more than simply catch visible particles. Compared with a compact under sink filter, it treats the main supply so the benefit is felt across the wider property.
If you are comparing whole house filter types, read our Complete Whole House Water Filter Comparison Guide before buying.
| Filter Type | Main Purpose | Best For |
| Sediment Filter | Particles, grit and visible sediment | Pre filtration and basic protection |
| Carbon Filter | Chlorine, taste and odour reduction | Improving mains water taste and smell |
| KDF and GAC Filter | Chlorine, metals, odours and organic material | Broader water treatment |
| Osmio PRO III XL | Multi stage whole house filtration | Premium filtration across the whole home |
Common Water Problems This System Helps Address
The Osmio PRO III XL is designed for households that want a broader solution than a simple drinking water filter. It helps reduce a range of common water quality issues found in mains water and general household water use.
- Chlorine taste and smell
- Unpleasant water odours
- Selected heavy metals
- Hormones and pesticides
- Organic material
- Hydrogen sulphide smells
- Fungi and algae
- Fluoride reduction
- Bacteria including E. coli and Pseudomonas
- Poor shower and bathing water quality
Whole House Filter Or Water Softener?
This is an important distinction. A whole house water filter is designed to improve water quality by reducing contaminants such as chlorine, taste, odour, sediment, metals and other unwanted substances. A water softener is designed to tackle hardness minerals that cause limescale.
If your problem is chlorine smell, chemical taste or general water quality, a whole house filter is the right category to consider. If your problem is scale on taps, white marks, kettle build up, shower screen staining or appliance scale, you need a water softener.
| Water Problem | Best Solution |
| Chlorine taste or smell | Whole house water filter |
| Unpleasant water odour | Whole house water filter |
| Sediment or particles | Whole house water filter |
| Limescale on taps and appliances | Water softener |
| Hard water marks | Water softener |
| Best overall home water setup | Whole house filter, water softener and drinking water RO system |
For homes in hard water areas, many customers choose to pair a whole house filter with a water softener. For the highest standard of drinking water, a separate reverse osmosis drinking water system can also be added at the kitchen tap.
System Components Overview
The Osmio PRO III XL includes three individual filter housings and three filter cartridges. This gives the system a broader treatment profile than a single housing system and allows each filter stage to perform a different role.
Housing 1: Active Ceramics Whole House Filter
4.5 x 20 inch antibacterial grey housing with Active Ceramics Whole House Filter. Replaced every 3 years or 300,000 litres.
This filter uses a patented blend of 4 active ceramics. It is designed to remove chlorine, hormones, fluoride and heavy metals while adding antioxidants and minerals back into the water. It also raises alkalinity and kills bacteria including E. coli and Pseudomonas.
Housing 2: Carbon Block 5 Micron Filter
4.5 x 20 inch carbon block filter. Designed to reduce chlorine, unpleasant taste, odour and selected VOCs. Rated for approximately 46,000 litres, with a typical service life of around 6 months depending on water quality and usage.
Housing 3: GAC and KDF Process Media Filter
4.5 x 20 inch GAC and KDF media filter. Targets chlorine, pesticides, organic material, hydrogen sulphide, metals, odours, fungi and algae. It is also useful for homes where lower pressure needs to be considered. Typical life is 12 to 18 months or up to 200,000 litres.
The system includes brackets, screws and a housing spanner. Installed footprint is approximately 655mm x 606mm.
Where Is The Osmio PRO III XL Installed?
This system does not need to be installed under the kitchen sink. It is normally fitted at the main cold water entry point to the property, before the water branches off to taps, bathrooms, showers and appliances.
Common installation locations include a garage, utility room, plant room or another suitable area close to the incoming mains water supply. The system should be installed in a location that allows access for future cartridge replacement.
Installation should be completed by a competent plumber. The system is designed for pipework up to 1 inch and performs best with suitable pressure and flow. Avoid installing if standing pressure is below 2.5 bar.
Whole Home Upgrade
Designed to improve water quality across taps, showers, baths and general household use.
Reduces Chlorine
Helps reduce chlorine taste, smell and related water quality concerns.
Less Bottled Water
Supports a more convenient household setup with filtered water available throughout the home.
Fast, Free Delivery
Available from Regal Flow with fast, free UK delivery.
What Is Included?
- Filter One: Active Ceramics filter, up to 3 years or 300,000 litres
- Filter Two: NSF 5 micron carbon block filter, typically 6 to 12 months
- Filter Three: KDF and GAC cartridge, typically 12 months
- 3 x antibacterial housings
- Mounting brackets and screws
- Large housing spanner
Maintenance And Cartridge Replacement
The Osmio PRO III XL is designed to be simple to maintain. There is no routine backwashing and no complicated regeneration cycle. Maintenance is based on replacing the cartridges when they reach the end of their recommended life.
Actual cartridge life depends on household usage, incoming water quality and flow demand. Homes with higher water usage or poorer incoming water quality may need to replace some cartridges sooner.
After use, the active ceramics can be added to soil as a fertiliser to support plant health and drainage. Plastic housing can be recycled where local recycling facilities accept the material.
Full Specification
| Total Height | 655mm |
| Total Width | 606mm |
| Maximum Pressure | 90 psi, 6 bar |
| Maximum Temperature | 45°C, 113°F |
| Service Flow Rate | Up to 70 LPM at 60 psi |
| Inlet and Outlet | 1 inch |
| Housing Options | Pressure relief vent valve |
| Standing Pressure Loss | Approximately 0.5 bar at 2.2 bar |
| Recommended Minimum Standing Pressure | Do not install below 2.5 bar standing pressure |
Warranty Information
The Osmio PRO III XL includes a 3 year warranty covering repair or replacement where defects arise from manufacturing issues.
You can register your warranty directly with Osmio here: Osmio Warranty Registration.
Installation And Maintenance Guide
Review the full installation and maintenance guide before purchase to confirm suitability for your property and installation location.
Frequently Asked Questions
Does the Osmio PRO III XL remove limescale?
No. Whole house water filters do not remove limescale. If you want to reduce limescale, hard water marks and scale build up, you need a water softener. View our Water Softeners collection.
Does this system filter water for the whole house?
Yes. When installed at the main incoming cold water supply, the Osmio PRO III XL is designed to filter water before it travels around the property. This means taps, showers, baths and general household water can benefit from filtration.
Does the Osmio PRO III XL remove chlorine?
Yes. The system is designed to reduce chlorine, taste and odour using its carbon block and GAC with KDF filtration stages.
Does it remove fluoride?
The active ceramics filter stage is designed to reduce fluoride as part of its broader filtration performance.
Can it help with shower water quality?
Yes. Because the system is installed on the main supply, it can help improve the water used for showers and baths as well as kitchen and bathroom taps.
Will it reduce water pressure?
Any whole house filter can create some pressure drop. This system has an estimated standing pressure loss of approximately 0.5 bar at 2.2 bar. It should not be installed if standing pressure is below 2.5 bar.
How often do the filters need replacing?
Filter life varies by cartridge. The active ceramics filter is rated up to 3 years or 300,000 litres. The carbon block filter is typically 6 to 12 months. The GAC and KDF cartridge is typically around 12 months, with potential life up to 12 to 18 months depending on water quality and usage.
Can this system be installed in a garage?
Yes, provided the garage is suitable, protected from freezing temperatures and gives access to the incoming mains water supply. The system must remain accessible for cartridge replacement.
Is this suitable for a larger home?
The system is designed for homes requiring higher flow performance and works best at flow rates up to 70 LPM. Suitability depends on water pressure, plumbing setup and household demand.
Do I still need a reverse osmosis system?
A whole house filter improves water quality across the property, but reverse osmosis is still the gold standard for dedicated drinking water filtration. Many customers use both: a whole house filter for general home water and a reverse osmosis system for drinking water.
Need Help Choosing the Right Whole House Filter?
Speak directly with our team for clear advice before placing your order.
Contact Support Team
Email Support: info@regalflow.co.uk
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