Review: APEC RO-90 Ultimate Series Reverse Osmosis System

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As part of the Ultimate Series, the APEC RO-90 Reverse Osmosis System is one of the company’s flagships providing relatively fast filtration and enough water for large families. This plus the 4-gallon storage tank eliminates waiting times – all for an affordable price.

But there is more to the APEC RO-90 that’s important to know – both good and bad things. We’ll discuss everything in our review below!

APEC RO-90 Ultimate Series Reverse Osmosis System

APEC RO-90 Ultimate Series Reverse Osmosis System

Price: $$
Filter Stages: 5
Water Flow: Not Specified
NSF Certifications: 58
Annual Cost: ~$70-80

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

APEC RO-90 Ultimate Series Reverse Osmosis System – All Specs

  • Model: RO-90
  • Annual Maintenance Cost: ~$70-80
  • Filter Media/Process: Sediment Filtration, Activated Carbon, RO
  • Filter Stages: 5
  • Membrane Rating: 90 gpd
  • Recovery Rate: 25%
  • Filtering Capacity: 1-5 Years
  • WxHxD: 16.0″x17.5″x5.25″
  • Tank: 11″x15″x11″, 4 gal
  • Water Temperature: 40-100 °F
  • Water Pressure: 40-85 psi
  • Water pH: 2-11
  • Fitting: 3/8”-1/2″
  • NSF Certifications: Standard 58
  • Warranty: 1-Year Limited

APEC RO-90 – Key Features

First of all, what does the filtration process look like and which impurities will be removed? Well, we have 5 filter stages which is typical for under sink reverse osmosis systems:

  1. First, we have a polypropylene sediment pre-filter that traps dust, particles, rust and the like to protect the whole system and the reverse osmosis membrane in particular from clogging.
  2. Stages 2 and 3 are carbon block filters (5-micron nominal) to reduce chlorine taste and odor, cloudiness, and all kinds of organic chemicals like VOCs. Removing any chlorine is also important as it would otherwise damage the delicate reverse osmosis membrane.
  3. Speaking of which, the DOW FilmTec RO membrane in stage 4 takes care of up to 99% of arsenic-5, barium, cadmium, chromium-6, fluoride, lead, radium 226/228, selenium, bacteria & viruses, and overall TDS.
  4. Lastly, a coconut-shell GAC post-filter removes residual tastes and impurities that might have leached into the water while being stored in the tank.

All in all, you can expect powerful filtration from the APEC RO-90 system for clean and healthy drinking water. By the way, this has also been NSF Standard 58-certified by the WQA. In other words, the reverse osmosis system is guaranteed to be effective (more on this below).

The recovery rate a.k.a. filtered-to-wasted-water ratio is about 1:3 which is pretty standard.

By the way, the APEC RO-90 is for tap and well water. The latter requires adequate disinfection, though.

Finally, we have a large 4-gallon storage tank so you should never run out of filtered water.

APEC RO-90 Ultimate Series Pros

Probably the most important advantage of the APEC Water Systems RO-90 is the relatively affordable price.

And apart from the solid filtration process, we like that filters are Made in USA and long-lasting (about 12 months) which reduces maintenance requirements. What’s more, the filters are standard-sized (10 inches) so it’s easy to find cheap aftermarket replacements if need be.

Speaking of filters, annual replacement cost amount to somewhere between $70 and $80 which is pretty cheap already. Plus, changing filters is not overly difficult and the same can be said about system installation.

Above that, there are 2 upgraded versions of the APEC RO-90 for sale:

  1. For one, the RO-PH90 that features an additional 6th remineralization stage to enrich your water with calcium carbonate for better taste and to balance water pH. Naturally, we are talking about food-grade calcite. FYI: The calcium will increase TDS levels which is normal.
  2. Secondly, the RO-Hi. The unit comes with a bigger output for increased flow rates from the tank to the faucet – up to 2x faster, says APEC. This allows you to draw more water from the system in a shorter time.

Did we mention that the APEC RO-90 Ultimate Series Reverse Osmosis System is backed by a 1-year limited manufacturer warranty?

What Contaminants Are Being Removed?

Thanks to the 5-stage filtration process, you get a good range of contaminant removal. Some of the addressed contaminants include:

  • Dust
  • Particles
  • Rust
  • Chlorine
  • VOCs and organic chemicals in general
  • Arsenic-5
  • Barium
  • Cadmium
  • Chromium-6
  • Fluoride
  • Lead
  • Radium 226/228
  • Selenium
  • Bacteria
  • Viruses
  • Copper
  • TDS

APEC RO-90 Ultimate Series Reverse Osmosis System

The APEC RO-90 Ultimate Series – learn more on


Installing the APEC RO-90 is like installing most other under sink reverse osmosis systems: You need to drill a hole in your kitchen sink or countertop for the dispenser in case there is none, install the drain saddle, and assemble the unit itself with all its connections.

The good news is that the system comes with clear step-by-step instructions including pictures.

If you are at least a little handy with tools you should be able to pull this off in a few hours.

Please consider these instructions as a general guideline. Always make sure to check and follow your user manual before getting started.

Tools you’ll need:

  • Variable speed drill
  • Drill bits – 1/4″, 1/8”, 1/2″
  • Adjustable wrench
  • Pliers
  • Screwdriver
  • Utility knife
  • Teflon tape

To set everything up, follow these steps:

  1. Set the 3 filter housings upright, ensuring each one has an O-ring in its groove.
  2. Insert a filter into each housing unit.
    1. Insert the sediment filter into the 1st stage housing.
    2. Insert the 2 carbon filters into the 2nd and 3rd stage housings, middle and left correspondingly.
  3. Twist each housing into the main system by turning it counterclockwise, starting with the 3rd stage housing on the left. Use the wrench for additional tightening.
  4. Find a suitable place under your sink for installing the system.
  5. Shut off the cold water supply.
  6. Connect the feed water adapter, using the needle valve that’s included in the package. Check the manual for specific installation instructions for individual connection sizes.
    1. If you’re using a flex line riser, loosen the nut on the flex line riser, and separate the cold water riser tube from the shutoff valve. Fit the feed water adapter into the shut off valve. Then, connect the riser tube, feed water adapter, shut off valve, and tighten everything together.
    2. Screw the needle valve onto the adapter tightly, using Teflon tape as necessary.
  7. Connect the needle valve – slide the metal compression nut, then the plastic sleeve, and then push the plastic insert into the red tubing.
    1. Push the red tubing into the needle valve connection until you feel a slight click.
    2. Push the plastic sleeve up to the needle valve connection, and finally screw the metal compression nut with the red tubing pushed into the needle valve.
  8. Now you’re ready to install the drain saddle. It should go above the P-trap and on the vertical or horizontal tailpiece. Drill a 1/4″ hole through the side of the drain pipe and add adhesive black sponge to the location.
  9. Install the drain saddle clip, aligning it with the tubing connection port onto the black sponge.
  10. Push 1/4″ black drain tubing into the quick connect fitting on the saddle.
  11. Drill a 1/2″ hole for the reverse osmosis faucet.
  12. Mount the faucet onto the new hole.
  13. Connect the clear faucet tubing to the system output.
  14. Find a suitable location for the tank. It should be no more than 20 feet away from the RO system.
  15. Hook up all remaining tubing, referencing the manual for your specific configuration/situation.
  16. Turn on the cold water.
  17. Open the tank’s ball valve.
  18. Wait for the tank to fill – this should take 2-3 hours.
  19. Drain the tank completely, and discard the first batch of water.
  20. Check for leaks.
  21. Done!


For additional guidance you can refer to this 5-part video series:

The Package (Parts)

  • RO system head
  • Filter cartridges
  • RO membrane
  • Storage tank
  • Drain saddle
  • Feed water adapter (3/8″-1/2″)
  • Faucet
  • Colored tubing
  • Housing wrenches
  • Tank ball valve
  • Faucet adapter
  • Teflon tape
  • Manual


With home reverse osmosis systems in general, only little maintenance is required. This also goes for the APEC RO-90. All you need to do is remember to change filters according to schedule which is not overly complicated, and occasionally clean/disinfect the system and check storage tank pressure.

Here is how long each filter stage lasts:

  • Sediment pre-filter – 12 months
  • Carbon block pre-filter – 12 months
  • Carbon block pre-filter – 12 months
  • Dow FilmTec RO membrane – 3-5 years
  • Carbon post-filter – 3-5 years

As mentioned before, average annual replacement costs of $70-80 are A) very affordable and B) less than we had expected.

To change the pre-filters:

  1. Shut off the cold water supply.
  2. Turn off the tank ball valve.
  3. Turn on the RO faucet lever shortly to release the pressure.
  4. Open the filter housings by turning clockwise.
  5. Discard the old filters.
  6. Wash the housings with soapy water.
  7. Install the new filters, paying attention to ensure that each one goes into the correct housing.
  8. Close each housing.
  9. Turn on the cold water supply.
  10. Turn on the RO faucet lever.
  11. Leave water running for 10-15 minutes.
  12. Turn off the RO faucet lever.
  13. Turn on the tank ball valve.
  14. Check for leaks.

To replace the reverse osmosis membrane:

  1. Turn off cold water supply.
  2. Turn off tank ball valve.
  3. Turn on the reverse osmosis faucet lever for a little while to release the pressure.
  4. Disconnect the white tubing from the RO membrane housing’s cap.
  5. Open the cap.
  6. Take out the membrane.
  7. Remove any leftover water by tilting the system slightly.
  8. Insert the new membrane – avoid touching it with your bare hands.
  9. Close the housing cap.
  10. Reconnect the white tubing to the cap.
  11. Turn on the cold water supply.
  12. Turn on the tank valve.
  13. Let the system run for a couple of hours to refill the tank.
  14. Drain the first tank and discard it.
  15. Check for leaks.

To replace the carbon post-filter:

  1. Remove the old filter – unclip it from the membrane housing, and then discard it.
  2. Use a mild bleach solution to rinse the plastic ports of the Tee fitting and the open port of the new filter.
  3. Connect the new filter, observing the correct direction of the “FLOW” arrow.
  4. Check for leaks.


Here is a link to the official manual:

NSF and Other Certifications

The APEC RO 90 has one important NSF certification:

  • Standard 58: For material and parts safety, structural integrity, as well as the reduction of arsenic (V) (300 ppb influent level), barium, cadmium, copper, fluoride, chromium-6, lead, radium 226/228, selenium, TDS, turbidity.

Earlier Product Versions

We couldn’t find any earlier product versions.

APEC Water Systems RO-90 Cons

We couldn’t find specific contaminant reduction rates. This is not so much of a problem because we have a certification against NSF standard 58, but for comparability it would have been nice to have specific rates. Also the certified contaminants are a great start but they’re limited in regards to their type. They’re basically all ions, and certification for some organic chemicals would have been nice.

A few more cons:

  • This is one of the older style RO systems that don’t use a pressure pump and that’s why water flow is much slower and a lot of water gets wasted (around 75% of the input water).
  • The system doesn’t combine tubing, filters, and the tank in one body like some other models do, leading to potential cluttering beneath your sink.
  • Filters may clog prematurely.

APEC RO-90 Review: Our Verdict + Best for

The APEC RO-90 Ultimate Series Reverse Osmosis System combines affordability with NSF-backed contaminant reduction. But this is one of the older-style under sink RO systems that lack features such as a pressure pump for faster filtration and reduced wastewater. All in all, we award 4 stars.

Our Rating in Detail:

  • Filtration Performance: 4.0/5.0
  • Filter Capacity (Life): 5.0/5.0
  • Purchase Price: 5.0/5.0
  • Annual Cost: 5.0/5.0
  • Overall: 4.0/5.0

Comparison to Other Reverse Osmosis Systems

There are other options available on the market if the APEC RO-90 doesn’t fit your needs. Two of our top choices are the Waterdrop G3 and the AquaTru.

Waterdrop G3 Reverse Osmosis System (G3P600)

Waterdrop G3

Price: $$$
Filter Stages: 4
Flow Rate: 0.42 gpm
NSF: 58, 372
Annually: ~$145

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

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AquaTru Reverse Osmosis Water Filtration System


Price: $$$
Filter Stages: 4
Water: 1 Gallon in 10-15 Minutes
NSF: 42, 53, 58, 401, P473
Annually: ~$100-120

Overall Rating: 4.5/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

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APEC RO-90 Ultimate Series Reverse Osmosis System


Price: $$
Filter Stages: 5
Flow Rate: Not Specified
NSF: 58
Annually: ~$70-80

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

The Waterdrop G3 is a tankless under sink reverse osmosis system (click to read the full review). It filters water on-demand and has no storage, making it quite sleek compared to a tank-based system like the APEC. The Waterdrop G3 comes with 4 filtration stages, performance backed by solid NSF testing (Standards 42, 53, 58, 401) and one certification (standard 58 for TDS reduction). Waterdrop provides these contaminant reduction rates:

  • Chlorine: 99%
  • VOCs: 99%
  • Nitrate: 98%
  • Fluoride: 99%
  • Arsenic: 99%
  • Chromium-6: 99%
  • Lead: 99%
  • PFOA/PFOS: 99%

The system also utilizes an internal pump boosting water pressure, and can achieve a flow rate of 0.42 gallons per minute – much faster than the APEC and more than enough for the average household, as it allows you to fill 1 cup of water in about 8 seconds. In addition, only 33% of the input water is wasted (compared to 75% with the APEC). Installing the system is simple and straightforward.

You also get the benefit of a smart faucet, which lets you know when it’s time to replace your filters with visual and sound clues. The filters themselves last for between 550 and 2200 gallons, which comes down to 6-24 months, and replacing them is pretty easy. You can even do it without shutting off the water first, and without using any tools!

You’re able to see the current TDS level of your water with the help of a built-in monitor. The system is made of BPA-free materials, and is backed by a money-back satisfaction guarantee for the first 30 days. You also get a 1-year warranty on top of that – but keep in mind that it’s only valid when used with municipal water.

The only real downsides are that the Waterdrop G3 can occasionally produce annoying noises, and it costs quite a bit more than the APEC, both initially and in annual maintenance, which comes down to around $145 per year.

The AquaTru is hands down our favorite reverse osmosis system. It’s a countertop unit designed to be very easy to set up and use, requiring practically no installation. The system is tested and certified against various NSF standards for more than 80 contaminants. You get certificates for NSF/ANSI standards 42, 53, 58, 401, and P473, which is quite impressive compared to other systems, including the APEC. The contaminants targeted include:

  • Chlorine: 96.6%
  • VOCs: 95% – 99%
  • Chromium-6: 97.2%
  • TDS: 87.1%
  • Cyst: 99.99%
  • Fluoride: 93.5%
  • Lead: 99.1%
  • Radium 226/228: 96.4%
  • BPA: 99%
  • Pharmaceuticals and pesticides: 86.7% – 96.6%
  • PFOA, PFOS: 97.5%

What’s more, the AquaTru takes up very little space, and as we said above, requires almost no initial setup before it’s ready to use. It also filters quite fast compared to other reverse osmosis systems, and only wastes around 20% of the input water – again thanks to a built-in pump. The whole system is made with BPA and BPS-free Tritan plastic. Unfortunately, some users report occasional leaks, as well as units breaking down prematurely. Those appear to be rare incidents though. The only other downside we can point out is that the AquaTru costs more than the APEC upfront, and is also slightly more expensive in terms of annual maintenance which costs around $100-120.

If you have to choose between the three, we recommend going with the AquaTru due to its great balance of price, maintenance cost, NSF certifications, ease of installation, fast filtration, and low wastewater. The Waterdrop G3 comes in second, and we especially appreciate its tankless design and fast operation. The APEC RO-90 is only really recommended if you’re on a limited budget. Its NSF certification is good, but keep in mind that it doesn’t come with advanced features like a pump, resulting in issues like a lot of wastewater and slow operation. It also takes more time to install the system, and its contaminant reduction rates are not as clear.

This completes our review of the APEC RO-90 Ultimate Series Reverse Osmosis System. If you have any questions please don’t hesitate to leave a comment below!

About the Author Alexandra Uta

Alex is a content writer with an affinity for research and a methodical attention to detail. Since 2020, she has fully immersed herself into the home water treatment industry only to become an expert herself. Alex has been using water filters and similar products for years which has gained her lots of hands-on experience.
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