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APEC RO-CTOP-C Countertop Reverse Osmosis Review

Overview of the Portable APEC RO-CTOP-C

The APEC RO-CTOP-C Portable Countertop reverse osmosis system allows you to enjoy reverse osmosis filtered water when the installation of an under-sink system is not practical, allowed, or when you are in a temporary location.

The system is advertised as being “installation free” since all that is needed to get this system up and running is to attach it to a standard faucet in place of the aerator (sprayer, pull-out, or designer faucets won’t work).  Once connected, the entire unit will sit on the counter next to the sink.

The faucet adapter has a clever design that allows you to switch between sending water to the RO system or normally through the faucet.  It also contains the waste water tube, so that waste water can flow down the sink drain.

Although this is a small system in terms of size (16 inch x 6.5 inch x 6.5 inch) and weight (only 7 lbs.) it can produce up to 90 gallons per day through 4 stages of filtration. This output is highly dependent on the temperature and pressure of the feed water but matches the output of many undersink reverse osmosis systems.

Not only does this system have a surprisingly large output, it is also highly efficient. For every gallon of filtered water produced, only 2 gallons are wasted for flushing the RO membrane.  This is lower than the average of 3 gallons wasted with other systems.

There are other options for countertop water filters, so if this is not what you are looking for, check our our reviews of competing systems including other countertop styles that don’t connect to a faucet or would have a dedicated reverse osmosis water faucet.

One drawback with the APEC RO-CTOP-C system is that it does not have a storage tank that will provide a reservoir of filtered water.  If the source water pressure or the temperature of the water is low, it can take a long time to fill a container with purified water.  High water pressure will definitely benefit this system.

Despite the limitations, many people give the RO-CTOP-C high ratings for working well in their apartment, hotel room, RV and other places where an under-sink system is not possible.

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Filtration System Design

The APEC RO-CTOP-C system is very compact with all the filters, including the RO membrane, clipped to a back plate and enclosed in a cover. There is a single hose that dispenses the pure water and a double hose that attaches to a faucet for feed water and waste water.  

The stage 1 and 2 filters, which need changing about every 6 months depending on the quality of the feed water, are self-contained. All that needs to be done is to remove the hoses via the push fit connectors, clip out the old filter and clip in the new filter. Then reattach the hoses and the filter change is complete.

The first stage is a sediment filter to remove dust, rust, and large particles.

The second stage is a activated carbon filter that removes chlorine, odors, and colors.

The third stage is a reverse osmosis filter that removes up to 99% of TDS and contaminants.

The fourth stage another carbon filter for final removal of tastes and smells.

The stage 4 filter, which needs changing in between 2 and 5 years of use is replaced in exactly the same way as the 1st and 2nd stage filters except that the push fit connector has a locking clip which needs to be removed first.

Replacing the RO membrane after 2 to 5 years of use is a little more involved but not difficult. First, remove the tubing from the membrane housing cap, then remove the housing cap. Using a pair of pliers, pull out the old membrane. Insert the new membrane, making sure that the end with the 2 black “O” rings is inserted first. Replace the end cap and the tubing. Run water through the system for about 15 minutes to flush the membrane and the system is now ready for use.

Water Efficiency

Surprisingly, this system is more efficient than many larger under-sink systems. To produce 1 gallon of purified water, only 2 gallons of water is wasted. This compares quite well to the average 3 gallons of waste water on many fixed installation systems.

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Ease of Installation

This system is very quick and easy to install. A full copy of the manufacturer’s installation and user manual can be found on the APEC website. 

APEC RO-CTOP-C faucet installation

The APEC RO-CTOP-C system can be installed onto a faucet with an aerator in minutes. The system comes with a selection of adapters to make it fit onto a variety of faucets.  The aerator should be unscrewed by hand, but if it has been there for some time or was over tightened when it was originally installed, you may need to use some large pliers to loosen it.

When the aerator has been removed, screw in an adapter (if necessary), then attach the connector valve to the faucet. Turn the faucet to maximum and open the feed valve.  

After a few moments, water will start to come out of the system outlet pipe. Allow water to run through for about 15 minutes to flush the system. The water is then ready to drink.

If the water is very cold, a little hot water can be added to make it warmer (but NOT hot). Warmer water will increase the system output.


  • Portable system that is quick to install and easy to move
  • 90 gallons of purified water produced each day is one of the highest of any system we recommend
  • 2 gallons of wasted water per 1 gallon of reverse osmosis water is lower than average
  • Weighs only 7 lbs.
  • Removes up to 99% of contaminants
  • U.S. based technical support which is free for the lifetime of the product
  • 1 year limited manufacturer’s warranty
  • Manufactured in the USA
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  • No storage tank for on-demand water
  • Even with high water pressure, it can take a while to fill a large container
  • Doesn’t work with all faucet types
  • Filter changes take more effort than other systems

Visit our reviews of the top countertop water filter systems to compare the APEC RO-CTOP-C with the competition.


The APEC RO-CTOP-C reverse osmosis system is a very good solution to a problem that people who live in rented homes, are students, or are travelers my face – it allows them to have pure, filtered water wherever they are.

The system can be set up and will produce pure, clean water in minutes.  When it is time to move it, just replace the original faucet aerator and there is no sign that the system was ever there. 

The big drawback with this system is that there is no storage tank, but it’s still the best option when you want clean drinking water from a temporary installation.

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This system is also available in the RO-CTOP-PH version which adds a calcite reminerlization stage for filtered water that has a higher pH and more of a “mineral water” taste.

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Our top rated add-ons for this or any other RO system will help you customize your installation!

APEC RO-CTOP-C Replacement filters

You can refer back here to order replacement filters as necessary.  It may help to order your first filter set now so you are ready in six months.