Review of APEC Ultimate Series RO-90 Reverse Osmosis Drinking Water System

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As part of the Ultimate series, the APEC RO-90 Reverse Osmosis Drinking Water System is the company’s flagship providing about twice the amount of water that you get with a standard RO unit – great for large families!

This is mainly due to the high-output RO membrane rated at 90 gallons per day (at 60 psi).

Please note: These are only theoretical numbers. The system will NOT produce 90 gallons a day due to backpressure and other factors. However, it will supply more than enough water for drinking and cooking.

Of course, higher water output also means higher flow rates which is the main benefit, really, as it eliminates long waiting times.

APEC Ultimate RO-90

APEC Ultimate RO-90

Price: $$
Filter Stages: 5
NSF Certifications: 58
Annual Cost: $$
Warranty: 1 Year

Our Rating

APEC Ultimate RO-90 Reverse Osmosis System – Key Features

What does the filtration process look like and which impurities will be removed?

First, we have a polypropylene sediment pre-filter that traps dust, particles, rust and the like to protect the whole system and the membrane in particular from clogging.

Stage 2 and 3 are carbon block filters to reduce chlorine taste and odor, cloudiness and all kinds of chemicals. Removing the chlorine is also important as it would otherwise damage the delicate RO membrane.

Speaking of which, the membrane takes care of the following contaminants:

  • Arsenic-5 (99%)
  • Barium (98.8%)
  • Cadmium (98.3%)
  • Chromium-6 (98.3%)
  • Chromium-3 (99%)
  • Copper (98.4%)
  • Fluoride (93.8%)
  • Lead (96.8%)
  • Radium 226/228 (98.8%)
  • Selenium (97.9%)
  • TDS (98-99%)

Last but not least, a carbon refining post-filter removes residual tastes and impurities that might have leached into the water while being stored in the tank.

This filtration process has earned the APEC Ultimate RO-90 a WQA Cold Seal certification according to NSF Standard 58 for guaranteed material and parts safety, structural integrity and contaminant rejection performance (TDS only).

The recovery rate a.k.a. filtered to wasted water ratio is 1:3 which is pretty standard (every home RO system will waste some water).

Min/max required water pressure: 40-85 psi

Max TDS: 2000 ppm

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

RO-90 Pros

Apart from the sophisticated 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 so it’s easy to find cheap aftermarket replacements if need be.

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 made in the U.S. FYI: The calcium will increase water TDS 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 ideal for filling large pitchers.

Did we mention that the system is backed by a 1-year limited manufacturer warranty (2 years with registration) for peace of mind?

APEC Ultimate RO-90

The APEC Ultimate RO-90 – learn more on


Installing the APEC RO-90 is like installing any other reverse osmosis under sink system: 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 1 or 2 hours.

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

Parts List

  • System module with preinstalled membrane and post filter
  • Pre-filters + housings
  • 90 gpd TFC membrane
  • Lead-free chrome faucet, 360° rotatable + washers + nut
  • Faucet adapter
  • Color-coded tubing (food grade)
  • 4 gallon storage tank
  • Housing wrenches
  • Drain saddle
  • Tank ball valve
  • Feed water adapter (1/2″ or 3/8″)
  • Teflon tape
  • Manual
  • Only RO-PH90: Calcite filter

Filter/Membrane Replacements

With home reverse osmosis systems in general only very little maintenance is required. This also goes for the RO-90. All you need to do is remember to change filters according to schedule.

For stages 1, 2 and 3 that is once a year (if not changed in a timely manner the membrane might be damaged).

The membrane lasts for 3 to 5 years on city water and 2 to 3 years on well water.

The carbon post-filter is also good for 3-5 years.

The average annual replacement costs are A) reasonable and B) less than we had expected.

Only the optional remineralizing filter that needs to be replaced every 6-12 months seems a bit pricey.


  • Manual for the standard APEC RO-90
  • Manual for the APEC RO-PH90

RO-90 Cons

We like the fact that APEC provides certified, knowledgeable support based in California. What we don’t like is that the support can be hard to reach, according to a handful of Amazon reviewers.

Also, some customers had issues with bad taste that might originate from the storage tank.

For a few others the system stopped working out of nowhere.

APEC Ultimate RO-90 Review: Our Verdict + Best for

The APEC RO-90 saves you the time, money and inconvenience of buying bottled water.

Water quality is excellent and flow rates fast enough to provide plenty of pure H2O even at times of peak consumption.

Bottom line: The vast majority of users are happy with the product. 4.5 stars!

In our opinion, the APEC Ultimate RO-90 is best for people who want a reverse osmosis system with high water output.

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This completes our APEC RO-90 review. 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. Her writing interests have included many different topics, water treatment among them, which have encompassed varying writing styles.
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