Under Sink Water Filter Reverse Osmosis

Bottled water is convenient, but it is expensive over time and creates plastic waste. An under-sink reverse osmosis (RO) system treats tap water at the kitchen sink instead.

In this guide we explain how under-sink RO works, what to compare between models, and which systems are worth a look.

Benefits of Under Sink Reverse Osmosis Systems

• Broad contaminant reduction: RO membranes reduce dissolved solids, and certified systems also reduce contaminants such as lead, fluoride, arsenic and PFAS. Exactly which ones depends on each system's certification.
• Convenient installation: Most under-sink RO systems can be installed by a handy homeowner or a plumber.
• Space-saving design: The unit sits in the sink cabinet rather than on the counter.
• Tankless options: Newer tankless designs, such as Waterdrop's G3 series, take up less cabinet space than tank-based systems.

How to Choose an Under Sink Reverse Osmosis System

1. Certifications: Look for certification to NSF/ANSI 58 (the RO standard) from NSF, WQA or IAPMO, and check the performance data sheet for the specific contaminants you care about.
2. Filter replacement cost and schedule: Add up the price of replacement filters and how often each one needs changing to get the real cost of ownership. Check current prices with the manufacturer.
3. Installation requirements: Check whether you need a drain saddle, a faucet hole and, for tankless units, an electrical outlet.
4. Space: Measure your sink cabinet before buying.

Systems Worth Comparing

• APEC ROES-50: A 5-stage, tank-based under-sink RO system. Check APEC's current certification listing before buying.
• Waterdrop G3P600: A tankless under-sink RO system. Waterdrop lists certification to NSF/ANSI 58 and 372.
• Not ready for RO? A certified pitcher or faucet filter is cheaper and needs no installation, but it will not match RO for dissolved solids or fluoride.

FAQ: Frequently Asked Questions

Q: How often do I need to replace the filters?

A: It depends on the system, your usage and your water quality. Pre-filters are typically changed more often than the RO membrane. Follow the manufacturer's schedule for your model.

Q: Can I install an under sink RO system myself?

A: Most under-sink RO systems come with installation instructions and can be installed by a homeowner with basic DIY skills or by a plumber.

Q: How do I maintain my under sink reverse osmosis system?

A: Replace the pre-filters and post-filters on schedule, replace the RO membrane when the manufacturer recommends, and sanitize the system if the instructions call for it.

Verdict

An under-sink RO system is a solid choice if you want treated drinking water on tap without buying bottled water. Choose a system certified to NSF/ANSI 58, check its performance data sheet against your water test results, and factor in the ongoing cost of filters.