4 Stage Ultrafiltration Alkaline Water Filter Under the sink

Our under sink filters vary by how many stages of filtration they use, each designed to meet different household needs. Twin-stage systems come in two versions: the Waco Twin uses a sediment filter followed by a carbon block to remove dirt, rust, chlorine, and chemical contaminants, making it ideal for improving basic water quality and taste. The Twin Ultrafiltration model replaces the sediment filter with a 0.03-micron ultrafiltration membrane, which also removes bacteria and viruses, offering a more advanced level of protection for homes with inconsistent water quality. Triple-stage systems offer more filtration; one version combines sediment, carbon, and ultrafiltration for reliable removal of particles, chlorine, and pathogens, while the alkaline model starts with ultrafiltration, then adds a mineral-rich alkaline filter to boost pH and improve taste, followed by a carbon stage for final polishing. Our four-stage systems offer the most complete filtration in our standard (Not Reverse Osmosis) line up. The standard version runs your water through sediment and carbon filters, an ultrafiltration membrane, and finishes with a second carbon stage to polish the taste. The alkaline model swaps that final carbon stage for an alkaline cartridge that boosts pH and adds healthy minerals like calcium and magnesium, then finishes with carbon to clean up any remaining taste or chemicals. The more stages your system has, the more protection you get from basic chlorine removal in our twin systems, to bacteria and virus filtration in triple models, all the way to smoother, mineral-rich water in our four-stage alkaline setups.

Under-sink multi-stage filters remove common tap water contaminants: sediment (dirt, sand, rust), chlorine (and the bad taste/odor from it), and organic chemicals like pesticides. The ultra-filtration membrane can also block bacteria, parasites and microplastics, and the carbon stages help reduce some heavy metals (e.g. lead). However, they do not remove dissolved minerals or salts – things like calcium, magnesium, and fluoride are generally not filtered out (which means healthy minerals stay in your drinking water, but fluoride and very fine dissolved solids will also remain).

No, standard under-sink ultra-filtration systems won’t significantly remove fluoride. Fluoride is a dissolved mineral, and our filters are not designed to eliminate it. Typically, only a reverse osmosis system can effectively reduce fluoride in water. So if fluoride removal is a priority (for example, for mixing baby formula or personal preference), you’d need to use an RO system, otherwise, the ultra-filtration system will leave the fluoride in while removing other contaminants.

Both are fine filtration methods, but they are different through their filtration methods. Ultra-filtration (UF) uses a membrane with about 0.01 micron pores that blocks sediment, bacteria, etc., but it lets dissolved molecules like minerals & fluoride pass through. Reverse osmosis (RO) uses an even tighter membrane (~0.0001 micron), which removes virtually all impurities *including* dissolved salt, minerals and fluoride. UF systems have no wastewater (all the water goes to your tap) and run on normal mains pressure with no tank. In short, RO gives a higher level of purification (removing things like fluoride and total dissolved solids), while UF provides clean, great-tasting water without the complexity – it retains natural minerals, and no water wasted.

The filtered water stream will be , especially with ultra-filtration systems, which naturally have a more restricted flow due to a finer membrane. The actual flow rate can vary and depending on the quality of your inlet water — higher sediment or poor-quality water can slow things down more. That said, our systems still deliver enough flow to fill a glass in a few seconds. If you’re using a separate filter tap, your main kitchen tap pressure won’t be affected. And if you install a 3-way mixer tap, your regular hot and cold water flow stays the same — only the filtered water comes through at a slower rate, which is still fine for drinking and cooking.

Generally, you should replace the filters about every 10 to 12 months​. In most Australian households with municipally treated water, an annual filter change is recommended to keep your water quality high. The replacement cartridges are readily available – you can buy them from us directly. Replacing the cartridges is straightforward: you just shut off the water, twist and pull out the old cartridges, and swap out the old cartridges for new ones​. The whole process only takes a few minutes, and no special skills are required.

No need to worry – this is a common occurrence when a new filter is installed, and it’s only temporary. Cloudy or milky-looking water is usually due to tiny air bubbles trapped in the cartridge, which make the water look hazy; these will dissipate after the initial flush​. If you see small black particles, those are just harmless carbon dust from the new carbon filter cartridge​. To fix both issues, simply flush the system by running the filtered water tap for a few minutes (around 5 minutes is usually enough). This will purge the air and rinse out any carbon fines, and your water will then be clear, clean, and ready to drink.

Yes, our under-sink filter systems can include a dedicated filtered water tap (a sleek, stainless steel tap) that you install on your sink or countertop. Most modern sinks already have a spare hole (used for a soap dispenser or spray hose) that can be repurposed for the filter tap; if not, you’ll need to drill a small hole (around 12mm) for installation. If you’d rather not add a separate tap, you can choose a 3-way kitchen mixer tap that combines your regular hot and cold water with filtered water in a single fixture. A 3-way tap replaces your existing kitchen tap and uses separate internal channels, so you get filtered water on demand without drilling an extra hole. If you already have a filtered water tap or 3-way mixer installed, you can also purchase the filter system on its own — it uses a standard 1/4" connection that fits most setups.

Our under-sink systems are designed with DIY installation in mind – many homeowners in Australia install them successfully on their own. The package comes with everything you need (tubing, fittings, and instructions) to tap into your cold water line and connect the filter and faucet. No electrical work is required, and the plumbing connection is similar to installing a dishwasher or kitchen tap. If you’re not comfortable doing it yourself, you can hire a professional​ plumber or handyman. In practice, a lot of people choose the DIY route or use a handyman – just be sure to follow the instructions and shut off your water supply during install.