Comparing the most common home water filters
| Filter Jug | Under-Sink Filter | Reverse Osmosis | Ceramic Gravity Filter | |
|---|---|---|---|---|
| Reduces common contaminants | Limited / depends on cartridge | ✓✓ | ✓✓✓ | ✓✓✓* |
| Reduces microplastics | Depends on cartridge | Depends on filter | ✓ | ✓ Up to 99.9% with Claii |
| Reduces PFAS | Depends on cartridge | Depends on filter | ✓ | ✓ Up to 95% PFOA & PFOS with Claii |
| Keeps natural minerals | Generally ✓ | Depends on filter | ✕ | ✓ |
| No installation | ✓ | ✕ | ✕ | ✓ |
| No drilling / plumbing | ✓ | Usually ✕ | Usually ✕ | ✓ |
| No electricity | ✓ | Usually ✓ | Depends on system | ✓ |
| No wastewater | ✓ | ✓ | ✕ | ✓ |
| Large water capacity | ✕ | N/A – direct from tap | N/A – direct from tap | ✓ |
| Suitable for renters | ✓ | Less convenient | Less convenient | ✓ |
| Long-term cost | Low initial cost, recurring cartridges | Varies | Higher initial & maintenance costs | Cost-effective, replacement filter only |
| Designed to stay on display | Depends | Hidden away | Hidden away |
✓ |
| How it's made | Mass-Production | Mass-Production | Mass-Production |
Handcrafted ceramic (Claii) |
*Filtration performance varies between ceramic gravity filters. Figures shown refer specifically to the filter element used by Claii.
1. Filter jugs
Filter jugs are one of the most accessible ways to start filtering your drinking water. They're relatively inexpensive, require no installation and can improve the taste of tap water.
However, their filtration is generally more limited than more comprehensive filtration systems and depends heavily on the cartridge being used. Their small filter cartridges also need to be replaced relatively frequently, meaning the low initial price doesn't tell the whole story.
Then there is the everyday practicality.
With a relatively small capacity, you're constantly filling the jug, waiting for it to filter, emptying it — and filling it again. If you're filtering water not only for drinking but also for cooking, coffee and tea, it can quickly become repetitive.
For a household that drinks a lot of water, a larger-capacity system can make everyday use considerably easier.
Best for: someone looking for a simple, low-cost introduction to filtered water rather than a higher-capacity, more comprehensive filtration system.
2. Under-sink water filters
Under-sink systems connect directly to your water supply, giving you filtered water straight from the tap.
They're convenient once installed and don't take up space on the countertop. The exact filtration performance varies considerably depending on the system and filter media.
The trade-off is installation. Depending on the system, you may need plumbing work and potentially a separate drinking-water tap.
For homeowners this might not be an issue. For renters — or anyone who simply doesn't want to make permanent changes to their kitchen — it can be less appealing.
Best for: someone who wants filtered water directly from the tap and doesn't mind installation.
3. Reverse osmosis
Reverse osmosis is one of the most extensive forms of household water filtration.
Water is forced through an extremely fine membrane, removing a very broad range of contaminants and dissolved substances.
But there is an important difference.
Reverse osmosis also removes most of the naturally occurring minerals in water, including calcium and magnesium.
Some RO systems therefore include an additional remineralisation stage to add minerals back afterwards.
RO systems also typically require installation and produce a wastewater stream during filtration.
For certain water-quality problems — such as high levels of dissolved salts or nitrates — this level of filtration can be exactly what is needed.
Best for: households that specifically need very extensive filtration or removal of dissolved substances.
4. Ceramic gravity water filters
A ceramic gravity filter takes a different approach.
Water is poured into an upper chamber and slowly passes through the filter using gravity alone.
No electricity.
No plumbing.
No drilling.
No wastewater.
And unlike reverse osmosis, ceramic gravity filtration allows naturally occurring dissolved minerals such as calcium and magnesium to remain in the water.
With Claii, the filter combines a ceramic barrier with activated carbon and specialised filtration media to reduce contaminants including microplastics, bacteria, cysts, chlorine, lead, PFAS and many organic chemicals.
Up to 99.9% of microplastics.
Up to 95% of PFAS such as PFOA and PFOS.
While keeping naturally occurring minerals.
Ceramic gravity filtration is a naturally slower process. Rather than using electricity or water pressure, the water gradually passes through the filter using gravity alone.
Claii filters approximately 1 litre of water every 1–1.5 hours.
With its 12-litre capacity, the idea isn't to wait for a glass of water to filter. Simply refill the upper chamber as you use the filtered water below, allowing Claii to continuously filter in the background throughout the day.
Best for: someone looking for effective everyday filtration while keeping natural minerals — without installation or permanent changes to the kitchen.