iSpring RCC7AK Review: Water Softening Under-Sink Filter

iSpring RCC7AK Review

What We Like

  • Softens and purifies water via reverse osmosis
  • Re-mineralizes and balances the water’s pH level
  • Includes a brushed nickel faucet
  • See-through sediment-filter housing for easy monitoring at a glance
  • High 75 GPD capacity

What We Don’t Like

  • Quite expensive
  • A bit difficult to install

Bottom Line

If you are looking for a highly effective water filter that can soften your water, be sure to check out iSpring’s RCC7AK.


The water supply in some areas might not have a very good taste and this is mostly due to dissolved minerals and salts. Borehole/ well water is usually characterized by having such properties and in some instances, might have harmful micro-organisms.

In such a case, it is best to use a reverse osmosis filter such as iSpring’s RCC7AK. This has 6 stages of filtration, which make it very effective. Let’s find out more about this product in the review below.

iSpring RCC7AK Review

iSpring RCC7AK

Photo: iSpring

Filtration Effectiveness: Softens Water

The greatest strength of this RCC7AK lies in its reverse osmosis system, which contains a membrane with very small 0.0001-micron pores. These only allow water to pass through and in the process, it blocks up to 99% of over 1000 harmful contaminants.

These include micro-organisms, chlorine, fluoride, arsenic, lead (98%), calcium, and sodium, just to name a few. As a result, the water exiting the system is free from the metal cations that cause it to be hard.

That said, the whole filtration process is not limited to reverse osmosis (RO), this is just a single stage in a 6-stage process.

It is the fourth stage and the three stages before it includes a PP sediment filter that removes large suspended particles, an activated carbon KDF filter that removes up to 98% of water-soluble cations such as lead, mercury, chromium, etc., and a carbon CTO filter.

This third filter reduces chlorine and odor to improve the water’s taste. Therefore, the water getting to the RO filter is already a bit clean and this helps to protect the membrane from corrosive chemicals such as chlorine and chloramines.

After this stage, water is moved to the 3.2-gallon reservoir tank and it can take anywhere from 1-3 hours to fill it up. This tank keeps clean water ready for use and it has a food-grade butyl diaphragm that helps to keep it pressurized for easy feeding to the faucet.

However, the water does not go directly to the faucet. It passes through two more filtration stages, with the first one being a carbon filter. This eliminates any residual taste and odors from the tank.

The final stage is pH filter and this increases water alkalinity while also giving back healthy minerals.

This stage is important because reverse osmosis does not do selective filtration. It eliminates almost every mineral in water, including the healthy ones and this lowers the pH to below 7, making it slightly acidic.

Therefore, stage 6 ensures you get healthy, naturally tasting water that has the quality of bottled water.

Installation: A Bit Complex

Installing this iSpring RCC7AK can be a bit complex because it has multiple components that must be joined together. First things first, you need enough space to fit it under the sink and it measures 15 x 8 x 18 inches when fully assembled.

There are a few tools that you need and these include a variable speed drill with 1/4” and 1/2” bits, an adjustable wrench, a Philips head screwdriver, and a pair of scissors or a utility knife.

Begin the process by drilling a hole on your countertop using the 1/2″ bit, then fit in the included faucet. Next, fit in the feed-water adapter to the cold-water supply line under the sink.

Install the drain saddle and you need to choose a convenient place on the drainpipe to fit it. A horizontal section of the drainpipe is recommended to minimize the dripping sound.

After this, set up the three pre-filters in a vertical position then install the shut-off valve on the reservoir tank. Finish off by installing the RO filter and the final two stages. You must install the tubes correctly, so that water flows from one filter to the next without mixing.

That said, detailed installation instructions are given in the user manual and these contain part diagrams with marked color-coded tubes to ensure you don’t get mixed up in the process.

Maintenance and Replacement: Different Lifespans

There are 6 stages of filtration, which means 6 filters need to be replaced every once in a while. 5 of them (excluding the RO membrane) must be changed every 6-12 months while the RO membrane must be changed every 2-3 years.

That said, changing the pre-filters (stage 1-3) requires you to twist the filter housing without removing the system from the wall. However, if there isn’t enough space under the sink, you have to pull out the whole setup from the wall to remove the individual filters.

After this, twist the filter housing counterclockwise to access the filter. Remove then replace it with the respective cartridge for each stage.

As for the RO membrane, the TDS (Total Dissolved Solids) level determines if it is functioning properly or not. Therefore, you should monitor this frequently and if the TDS rejection rate goes below 90%, a replacement is due.

This usually takes about 2-3 years and depends on the quality of the water supply, replacement of the pre-filters, and water usage. That said, replacing the membrane requires a high level of precision. Detailed instructions are included in the user manual to guide you in this process.

For stages 5 and 6, replacing the filter is quite easy because you only have to remove the water tubes, unscrew the fittings on both ends of each filter, then fit in the new ones.

You can choose to buy these replacement filters independently but they are available as 1-year, 2-year, and 3-year sets, which give you the best value for money.

Another important step in the maintenance process involves the tank and this should be completely emptied then refilled once a month to keep the water inside fresh.

Operating Conditions

For the RO filter to function efficiently in this system, the water supply should be at a minimum pressure of 45 PSI and a maximum of 70 PSI. Otherwise, you need a booster pump or a pressure regulator to raise or lower the pressure respectively.

The filter is not designed to deal with extremely cold or extremely hot water. It has an operating temperature range of 40-100ºF and due to this, it should also not be placed where it’s too hot or too cold.

Other than that, the water supplied to the unit should not exceed a maximum TDS of 750 ppm.

That said, with all these conditions met, you can extend the capabilities of this filter by linking it up with your refrigerator. Using the iSpring ICEK, you can bypass the faucet and connect it directly to your fridge’s ice maker or water dispenser.

This method is superior to inline fridge filters as it ensures you get crystal clear ice cubes and great tasting cold water.

In case you have a vacation, work trip, or any other event that will require you to be away from home for more than a week, ensure you leave the reservoir tank empty and close the water supply to the filtration system.

Also, remove the RO membrane and store it in a damp resealable zipper bag in your fridge. It can break apart and lose effectiveness if left in a dry state.

Price: Quite Costly  

Due to its advanced reverse osmosis filtration system, it is expected that this RCC7AK has the price to match and it does because it costs about $200.

However, it is very reliable and comes with a lead-free brushed nickel faucet as an accessory to complete the setup. This gives you value for money.

That said, this model is actually the cheapest in iSpring’s lineup of RO filters. In comparison, there is the iSpring RCC7P-AK, which has a booster pump that addresses the problem of low water pressure from the supply lines.

This is meant to provide consistent and efficient performance in the reverse osmosis filtration process. However, it makes this model more expensive but it costs less than $300. 


A reliable water softening filter that produces naturally tasting water, and is ideal for domestic use. 

With its RO filtration system, iSpring’s RCC7AK eliminates most cations in water to make it soft. The final pH filter stage gives back healthy minerals to the water, leaving it with a natural taste.

Despite having 6 stages, the filter has a flow rate of 75 GPD, which is enough for family use.


  • Product Name: iSpring RCC7AK
  • Product Brand: iSpring
  • Filtration: 6 stage
  • Filtered Water to Waste Water Ratio: 1:3
  • Production: 75 GPD
  • Operating Temperature Range: 40 – 100 °F
  • Operating Water Pressure: 45 – 70 PSI
  • Micron Rating: 0.0001
  • Product Dimensions: 15 x 8 x 18 inches  
  • Weight: 20 lbs.
  • Warranty: 1-year (1-year money-back guarantee)

Key Features

  • 6-stage filtration with reverse osmosis and alkaline remineralization.
  • Includes a European-style kitchen faucet.
  • Reinforced 1’st stage transparent housing.
  • Includes a 3.2-gallon pressurized storage tank.
  • High 75-gallon/day capacity RO membrane.
  • Comes with a drain saddle to serve the drain pipe.