There are differing ideas about what pure water actually is. Many people want a filter that takes everything out and just leaves the H2O. While that may be great for car batteries, there are minerals in drinking water that are vital for health. A better, more healthy definition of purified water is water that has had the unwanted impurities taken out - which is exactly what the Moby Water Purifier does.

Is the Moby Water Purifier better than reverse osmosis?

For most households it's the smarter choice. RO systems have five or more cartridges to replace regularly, and they discard most of the water that goes through them - usually 70% to 80%, or around 50% for the newer ''eco'' styled systems. The Moby Water Purifier has just two cartridges, unlikely to need changing more than annually, produces no waste water at all, and needs no electricity. RO will also remove dissolved salts and iodine, which the Moby Water Purifier deliberately leaves in.

Does it remove the minerals I need?

No, and that's deliberate. Calcium in carbonate form and magnesium are both retained - the very minerals that many newer RO systems have to add back in with an extra stage. It also leaves iodine in your water, which matters because there's an iodine deficiency problem in the UK, particularly among pregnant women who need it for the neurological development of their babies.

Does it remove bacteria and viruses?

Yes. The second stage is an Argonide NanoCeram 0.2 micron electropositive nano filter - technology developed for NASA to recycle water in spacecraft - which removes and reduces bacteria, viruses, cysts and a whole spectrum of other contaminants.

Does the Moby Water Purifier remove PFAS?

Yes. The carbon block stage reduces PFAS/PFOS forever chemicals, along with chlorine, VOCs, PAHs and other chemicals.

How often do the cartridges need changing?

It's unlikely you'll need to replace the two cartridges more than annually, though it depends on how much water your household uses. It's a simple job you can do yourself once the system is fitted.

Is the Moby Water Purifier difficult to install?

No. Installation is simple - unfiltered water in on one side, purified water out of the other, with no drain required and no electricity supply. It connects to your cold mains feed, and you choose your fitting kit when you order.

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Moby Water Purifier

Watts and Argonide

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A high performance mains water purifier that reduces a wide range of contaminants while retaining beneficial minerals. Delivers cleaner, better tasting drinking water straight from your existing kitchen tap.

Broad spectrum filtration reduces chlorine, PFAS (forever chemicals), microplastics, sediment and many other common contaminants.
Retains beneficial minerals such as calcium and magnesium, unlike many reverse osmosis systems.
No separate drinking water tap, storage tank or electricity required - filtered water is available directly from your existing kitchen tap.
High flow rate with no wastewater, making it an efficient alternative to reverse osmosis.
Easy DIY installation with high-capacity replacement cartidges for simple, low-maintenance filtration.

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Broad spectrum filtration reduces chlorine, PFAS (forever chemicals), microplastics, sediment and many other common contaminants.
Retains beneficial minerals such as calcium and magnesium, unlike many reverse osmosis systems.
No separate drinking water tap, storage tank or electricity required - filtered water is available directly from your existing kitchen tap.
High flow rate with no wastewater, making it an efficient alternative to reverse osmosis.
Easy DIY installation with high-capacity replacement cartidges for simple, low-maintenance filtration.

Home Water Purification - the ultimate guide to water purification.
Tap Water Contaminants Explained - learn about the most common types of drinking water contaminants.

Overview

The Moby water purifier is a premium two stage mains water purification system designed to reduce a broad range of contaminants while retaining naturally occuring minerals such as calcium and magnesium. Installed on your cold mains water supply, it delivers high quality drinking water directly from your existing kitchen tap without the wastewater, storage tank or electricity associated with many reverse osmosis systems.

Two stage purification combining a carbon block cartridge with a 0.2 micron NanoCeram filter for broad spectrum contaminant reduction.
Reduces chlorine, PFAS (forever chemicals), heavy metals, nitrates, endocrine disruptors, VOCs, PAHs, bacteria, viruses and cysts.
Retains beneficial minerals including calcium, magnesium and iodine (if present) for naturally balanced drinking water.
No waste water, no electricity and no separate drinking water tap required, making it an efficient alternative to reverse osmosis systems.
Simple DIY maintenance with just two replacement cartridges, typically changed once a year depending on water quality and usage.

Is tap water safe to drink? - Tap water may meet the standards, but does it meet your standards? Discover the difference for yourself.

Is this right for me?

Choose this if

You want a premium mains water purification system that reduces a broad range of contaminants while retaining naturally occurring minerals. The Moby Water Purifier is ideal if you want high quality purified water from your existing kitchen tap without the wastewater, storage tank or electricity associalted with many reverse osmosis systems.

Not ideal if

You need to reduce fluoride (our Oyster Triple Water Purifier includes a dedicated fluoride reduction stage), you only want purified drinking water from a single under sink filter (the Oyster Water Purifier may be a better fit), or you need to remove dissolved salts and minerals, where reverse osmosis remains the appropriate technology.

What to check before buying

Available space: allow a minimum of H 38cm x W 60cm x D 18cm for installation.
Connection size: choose the correct fitting kit for your plumbing - 1/2" (15mm), 3/4" (22mm), 1" BSP, or no ports if you're supplying your own.
Cartridge replacement: the purifier uses two cartridges, typically changed once a year depending on water quality and usage.
Sediment levels: if your mains water contains noticeable sediment, we recommend fitting a pre-filter to help protect the NanoCeram cartridge and maximise its service life.

How to Remove PFAS in UK Drinking Water - an in-depth article about forever chemicals and how to reduce your exposure.

What it reduces and what it doesn't

The Moby Water Purifier combines activated carbon block filtration with 0.2 micron NanoCeram technology to reduce a broad range of contaminants commonly found in treated mains water. Unlike reverse osmosis, it is designed to retain naturally occurring minerals, such as calcium and magnesium, while reducing unwanted contaminants that can affect water quality, taste, and safety.

What the Moby Water Purifier removes

The table below compares the contaminants reduced by the Moby Water Purifier with other common water treatment technologies.

Contaminants / Substance	NanoCeram	Carbon Block	RO	NF	UF	MF	Particulate Cartridges	Ultra Violet
Bacteria	✔		✔	✔	✔	✔		✔
Bromine		✔
Chemical Reduction		✔	✔
PFAS/PFOS		✔	✔
Chromium VI	✔		✔
Colloids	✔	✔	✔	✔	✔		✔
CTO		✔
Cysts	✔	✔	✔	✔	✔	✔	✔	✔
Dissolved Salts			✔
Endotoxins	✔		✔	✔	✔	✔
Ferric Iron	✔		✔
Iodine
Lead	✔		✔	✔	✔
Particulates	✔	✔	✔	✔	✔	✔	✔
Polysaccharides (TEP)	✔		✔	✔	✔	✔
Silica	✔		✔	✔	✔
Trace Pharmaceuticals	✔	✔	✔
Virus	✔		✔	✔				✔
VOC		✔	✔
RO = Reverse Osmosis, NF = Nanofiltration, UF = Ultrafiltration, MF = Microfiltration

As you can see from the table above, the combination of carbon block and NanoCeram® covers just about everything you'd want to remove, while also leaving in the health critical things your body requires.

What it deliberately leaves in

The Moby Water Purifier is designed to retain naturally occurring minerals such as calcium and magnesium while reducing a broad range of contaminants. Unlike reverse osmosis systems, it does not remove dissolved mineral salts that contribute to the natural composition of drinking water.

Because the system targets unwanted contaminants rather than stripping everything from the water, it provides an excellent balance between effective purification and maintaining the natural mineral content of your mains water.

How it works

The Moby Water Purifier uses a two stage purification process to reduce a broad range of contaminants while retaining naturally occurring minerals. Each stage is designed to target different types of contaminants, providing comprehensive purification without the wastewater or electricity required by many reverse osmosis systems.

Stage 1 - Carbon block filtration

The first stage uses a 100% coconut shell activated carbon block cartridge to reduce chlorine, chemicals and contaminants that affect the taste, odour and quality of mains water. It also helps reduce PFAS (forever chemicals), nitrates, VOCs, endocrine disruptors, PAHs and other chemical contaminants.

Stage 2- NanoCeram purification

The second stage uses an Argonide NanoCeram 0.2 micron electropositive filter, originally developed using technology for NASA applications. This high capacity filter helps reduce bacteria, viruses, cysts and a wide range of microscopic contaminants while allowing naturally occurring dissolved minerals to remain in the water.

Specifications

The table below summarises the key specifications of the Moby Water Purifier

Specification	Details
Stage 1	Carbon block cartridge - reduces chlorine, taste, odour, PFAS, nitrates, endocrine disruptors, VOCs, PAHs, bromine and other chemical contaminants
Stage 2	Argonide NanoCeram® pleated electropositive filter (0.2 micron) - helps reduce bacteria, viruses, cysts, endotoxins, colloids, lead, chromium VI, ferric iron, silica, particulates, polysaccharides (TEP) and trace pharmaceuticals

Dimensions	Minimum H 38cm x W 60cm x D 18cm
Stages	Two
Nano filter rating	0.2 micron
Connection sizes	1/2" (15mm), 3/4" (22mm) or 1" BSP ports (or supply your own)
Naturally occurring minerals retained	Calcium, magnesium, and other dissolved mineral salts*
Waste water	None
Electricity required	None
Installation	Indoor residential use
Maintenance	Replace both cartridges approximately every 12 months, depending on water quality and household usage

*Performance depends on local water chemistry, flow rate, system design and application. Claims apply when installed as a complete water purification system.

What's included

Everything you need to install the Moby Water Purifier on your mains water supply.

1 x activated carbon block cartridge
1 x Argonide NanoCeram® 0.2 micron purification cartridge
Choice of fitting kit: 1/2" (15mm), 3/4" (22mm), 1" BSP, or no ports if you're supplying your own fittings.
2 x big blue filter housings
1 x double housing bracket
2 x isolating flexis
1 x double check valve
1 x housing spanner
Fitting instructions

Installation & placement

The Moby Water Purifier installs on your cold mains water supply, delivering purified water without the need for a separate drinking water tap, storage tank or electrical connection.

Allow a minimum installation space of H 38cm x W 60cm x D 18cm.

For optimum performance, the cartridges must be installed in the correct order.

Carbon block cartridge (Stage 1)
Argonide NanoCeram 0.2 micron cartridge (Stage 2)

This ensures the carbon block removes chlorine and chemical contaminants before the NanoCeram cartridge provides final stage purification.

You can download the fitting instructions here. When it's time to replace the cartridges, simply follow our cartridge replacement guide.

Maintenance & running costs

The Moby Water Purifier is designed to be simple and economical to maintain. Under normal household use, both cartridges are typically replaced once every 12 months, although replacement frequency will depend on your water quality and the volume of water used.

Replacement cartridges are straightforward to fit, so ongoing maintenance can usually be carried out without the need for a plumber.

To help keep your purifier performing at its best, we'll send you a reminder email every six months so you know when it's time to check your cartridges.

Replacement cartridge sets are available whenever you need them.

FAQs

Is the Moby Water Purifier a good alternative to reverse osmosis?

For many households, yes. The Moby Water Purifier reduces a broad range of contaminants while retaining naturally occuring minerals such as calcium and magnesium. Unlike many reverse osmosis systems, it produces no waste water, requires no electricity and doesn't need a storage tank.

What does the Moby Water Purifier remove?

The two stage purification process helps reduce chlorine, PFAS (forever chemicals), heavy metals, nitrates, VOCs, endocrine disruptors, bacteria, viruses, cysts, sediment and many other contaminants commonly found in treated mains water. See the comparison table above for a full breakdown.

Does the Moby Water Purifier retain beneficial minerals?

Yes. The purifier is designed to retain naturally occurring minerals such as calcium and magnesium while reduce unwanted contaminants. This provides high quality drinking water without stripping out the minerals found naturally in mains water.

How often do the cartridges need replacing?

Under normal household use, both cartridges are typically replaced once every 12 months, although this will vary depending on water quality and water consumption. Both cartridges are straightforward to replace, and we'll send you a reminder email every six months to help you stay on schedule.

Can I install the Moby Water Purifier myself?

Yes. The purifier is designed for straightforward installation on your cold mains water supply using the correct connection kit. It requires no electricity, no drain connection and no storage tank, and once installed, future changes can usually be carried out without calling a plumber.

Will it affect my water pressure?

The Moby Water Purifier is designed to provide a high flow rate for everyday household use. As with any filtration system, some pressure loss is normal, but when correctly installed with clean cartridges, it delivers excellent flow without the significant reduction often associated with reverse osmosis systems.

* Occasionally Watts components may be replaced with other high quality items as a result of unexpected supply chain issues. This does not affect the quality of the product or its function. Brassware and other plumbing accessories are sourced from UK suppliers.