We are a family-owned, Hawaii-based business committed to improving the health and safety of our ‘ohana through clean drinking water.

We provide both point-of-use reverse osmosis (RO) systems and whole-house water filtration and softening systems.

We also offer local installation and ongoing customer support on Oʻahu.

Tap water can contain a variety of contaminants—like heavy metals, chemicals, and other impurities—that many basic filters can’t remove.

Filtered Hawaii’s systems help remove or reduce:

Chlorine, chloramine, and byproducts like TTHMs

PFAS / PFOS “forever chemicals”

Organic contaminants and VOCs

Sediment, rust, and taste- or odor-causing particles

Filtering improves the taste of your water and food, and gives peace of mind about what’s flowing through your pipes.

Reverse osmosis is a filtration method that uses a semi-permeable membrane to remove a very large range of contaminants—effectively the “gold standard” for water purification.

Our RO systems can remove up to 99% of many contaminants, including heavy metals, minerals, and other dissolved solids.

This means much cleaner, better-tasting water at your tap.

We stock Waterdrop RO systems—because they are reliable, high-performance, and well-suited for Hawaiian homes. 

Here are some popular models:

Waterdrop X16  — 11-stage filtration, 1,600 GPD, tankless design, with real-time TDS monitoring

Waterdrop X12  — 11-stage, alkaline remineralization to bring pH up

Waterdrop G3P600  — compact, fast flow, 1:1 pure-to-drain ratio

Waterdrop G3P800  — higher flow (800 GPD) for higher demand

Waterdrop K6 Hot & Cold RO Dispenser — instant hot and cold filtered water

Filter replacement depends on the model. According to our site:

The X16 and X12 share the same 11-stage filters. 

The G3P600/G3P800 have their own filter sets, typically replaced every 6 months, 1 year, or 2 years depending on usage. 

For whole-house filtration systems, the 5-micron sediment filter needs replacing every 6–9 months. 

For whole-house systems, we design your system to maintain full flow based on the number of bathrooms in your home, so you should not notice a drop in water pressure. 

For undersink RO systems, because many Waterdrop models are tankless, they deliver fast flow when you need drinking water. 

Our whole-house filtration has an option specifically for private well systems, including removing iron, sulfur, and manganese.

For RO, Waterdrop generally recommends municipal or treated feed water—if your well water has a lot of large particles, pre-filtration may be needed. 

We picked Waterdrop because:

Their tankless design (on many models) saves space and reduces bacterial risk. 

They offer multi-stage filtration + remineralization options for better taste. 

Their systems are water-efficient, with a lower “pure-to-drain” ratio than many older or less advanced RO units. 

They include smart features such as real-time TDS monitoring and filter life alerts. 

Waterdrop backs their systems with a warranty and ongoing product support. 

Yes, RO systems produce “waste” (concentrated) water—this is the rejected water that contains the filtered-out contaminants.

However, Waterdrop systems are designed to minimize waste: their tankless models can achieve more efficient pure-to-drain ratios.

Some people reuse the reject water for non-potable purposes (like mopping or watering plants).

Not necessarily. For undersink or countertop RO systems, installation is pretty straightforward with standard plumbing to a cold-water line and a faucet.

But for best results and peace of mind, Filtered Hawaii offers professional installation on O‘ahu, so you don’t have to worry about leaks, mis-hookups, or optimal placement.

Many RO systems strip out most minerals. That can worry people who think they’ll miss out on “healthy minerals.”
That’s why we offer Waterdrop systems with remineralization filters, which reintroduce beneficial minerals like calcium and magnesium for better taste and pH balance.

If you go with a remineralizing model (like the X12 alkaline), you’ll get clean, balanced water.

Great question! Here are some things to think about:

How much water do you use (just for drinking vs whole-house)?

Do you want tankless, under-sink systems or whole-house filtration?

Are you interested in alkaline/remineralized water?

Do you need hot/cold filtered water (like with the K6)?

How often do you want to change your filters?

If you’re not sure, reach out to us — we’ll help you select the best system for your ʻohana and water needs.

Just call 808-398-3283 or fill out the contact form on our website, and we’re happy to:

Schedule a consultation

Walk you through different systems

Provide a quote

Arrange for local installation