Are Under Sink Water Filters Safe? Here’s What You Need to Know

Clean, great tasting water is more than just a luxury, it’s essential for your health. If you're like most homeowners trying to upgrade your water quality, you've probably wondered: Are under sink water filters safe? The short answer is yes, but like any household system, it depends on choosing the right filter, maintaining it properly, and understanding how it works.

In this article, we’ll explore what under sink filter systems do, the types of systems available, how safe they really are, and what to look for when choosing the best under sink filter for your needs.

What is an under sink water filter system?

An under sink water filter system is a discreet and powerful water filtration solution installed directly beneath your kitchen sink. It connects to your cold water line and filters water before it reaches your kitchen tap, offering clean, filtered or purified water without the need for clutter on your bench top or refillable filter jugs.

Unlike simple filter jugs or faucet attachment water filters, under sink systems are plumbed in and provide on-demand filtration, usually through a separate dedicated drinking water faucet or by installing a 3 way mixer tap. They’re especially popular among households that want a reliable source of safe drinking water without installing a whole house filtration system.

Explore under sink water filtration solutions for Australian homes

Types of under sink filters: carbon vs reverse osmosis

There are two main types of under sink filter systems to consider: carbon filtration systems and reverse osmosis (RO) systems. Each offers distinct benefits, and the right choice often depends on your local water quality, health concerns, and personal preference.

Carbon Filtration Systems

Carbon filters are one of the most common types of under sink water filter systems. Typically, these use activated or compressed carbon to remove impurities from water through a process called adsorption. As water passes through the carbon, contaminants like chlorine, sediment, volatile organic compounds (VOCs), and some pesticides are trapped, leaving your water tasting cleaner and smelling fresher.

Pros of carbon filters:

•    Great at improving taste and odour
•    Effective for town water with chlorine
•    Easy to install and maintain
•    More affordable than RO systems

However, carbon filters typically do not remove fluoride, nitrates, or dissolved salts, which may be a concern depending on your water source.

Reverse Osmosis (RO) Purification Systems

Reverse osmosis systems take filtration a step further, known as purification. These systems force water through a semi-permeable membrane, which removes up to 99% of contaminants, including:

•    Fluoride
•    Heavy Metals e.g lead and mercury
•    Total Dissolved Solids (TDS)
•    Parasites and Cysts (e.g. Giardia & Cryptosporidium)
•    Microplastics
•    PFAS (forever chemicals)

Pros of RO Systems:

•    Extremely thorough purification
•    Ideal for homes with poor-quality tap water
•    Often includes multiple stages of filtration (carbon + RO + remineralisation)

Cons of RO Systems:

•    Can be more costly due to their multistage filters
•    Can waste some water during the rigorous filtration process
•    Requires more under sink space

Read more about the difference between filtration and purification here

Are under sink filters safe?

To ensure your under sink filter is safe it is important to follow all recommendations of the system:

•    Choose a certified system (look for NSF/ANSI certifications)
•    Follow the manufacturer’s maintenance schedule
•    Replace cartridges at the recommended time or litre usage
•    Ensuring professional installation

Poor maintenance, on the other hand, can compromise water quality. For instance, overused carbon filters may become a breeding ground for biofilm or start releasing trapped contaminants back into the water. That’s why it’s important to replace your water filter cartridge every 6–12 months or the recommended period.

Why replacing your water filter cartridge is the key to healthy water

Choosing the best under sink filter for your home

If you’re looking for the best under sink filter, consider the following criteria:

Know your water quality

Before choosing a system, understand what’s in your water. If you're on town water, a carbon under sink water filter system may be sufficient. But if your area has issues with heavy metals, fluoride, or PFAS, an RO system may be a better fit.

Check for certifications

Look for filters that are tested and certified by reputable bodies like:
•    NSF/ANSI 42 (for taste and odour)
•    NSF/ANSI 53 (for health contaminants)
•    NSF/ANSI 58 (for reverse osmosis systems)

These certifications ensure the filter does what it claims.

Consider installation and space

Many under sink water filter systems require permanent installation, if you're renting or don’t want to drill holes in your countertop, opt for a benchtop water filter instead. RO systems also require more space due to multiple filtration stages and a water holding tank.

Shop bench top water filters here

Budget and maintenance

Carbon systems tend to be more budget-friendly and have lower ongoing maintenance costs. RO systems have higher upfront costs, more components to replace, and sometimes require a professional to service.

Common concerns about under sink filters

Will it affect my water pressure?

Not noticeably. Most under sink systems are designed to maintain good flow, especially carbon systems.

Are they hard to install?

Generally, bench top water filters are easy DIY installation. However, under sink systems are typically recommended to be installed by a professional. Check with your local water authority or state plumbing regulations as they can vary between states and territories.

Can it filter hot water?

No – water filters are typically connected to the cold-water line only. Running hot water through a filter can damage the cartridge and reduce effectiveness.

Is it eco-friendly?

Yes, under sink systems significantly reduce plastic waste compared to bottled water. Some brands also offer recycling programs for used cartridges.

Read about all the best reasons to filter your water here

So, are under sink water filters safe? Absolutely - if you choose the right system for your needs and keep it properly maintained. Whether you're filtering out chlorine for better taste or removing fluoride and heavy metals for peace of mind, there’s an under sink filter system that can work for you.

Investing in the best under sink water filter system is not only a step toward safer water but also a healthier home and lifestyle.

Ready to make the switch?

Browse our range of under sink filter systems and find the perfect fit for your home. Or check out our reverse osmosis water filters for advanced protection.

For personalised advice, contact our team on 1300 808 966 or send us an email at info@purewatersystems.com.au