The Express Water ROALK10DCG is a 10 stage reverse osmosis filtration system. It’s plenty small, so you can easily place it underneath your kitchen sink and still have plenty of space left over. Now, the filter might be small, but it can still filter 100 gallons of water per day, which is more than enough to provide for a family of water ROALK10DCG

This article will discuss the filtration, efficiency, reliability, warranty, installation, and the maintenance.

I know it sounds like a lot, but it’s not too bad.

It’s the essential stuff that you should know before purchasing a reverse osmosis system.


Everyone wants to know about the filtration system before purchasing a unit, so that’s the first thing we’ll discuss.

As mentioned earlier, this unit has a 10 stage filtration system. That’s a lot compared to most systems that have 3-5 stages.

However, it’s mostly a marketing ploy. This is really a 6 stage system with the mineralization stage broken out four separate times. Other manufacturers typically count that step as one stage. A little sneaky on Express Water’s part, but don’t let that intimidate you. This system is still great.

Anyway, with that out of the way we can discuss the different filter stages.

Sediment Filter: A standard sediment filter. This targets the largest sediment and prevents the other filters from getting clogged.

Carbon Block Filter & Granular Carbon Filter: The 2nd and 3rd stage of filtration. These are standard activated carbon filters that remove chlorine. Chlorine will quickly destroy a reverse osmosis membrane, so you definitely want to filter it out before it reaches the reverse osmosis membrane. Carbon filters are much cheaper than the membrane.

Reverse Osmosis Membrane: The workhouse of this filtration unit. This removes over 1000 different contaminants, minerals, and other bad stuff found in water. It turns your water into the purest water available. So pure, that the next steps actually add essential minerals back into the water.

Alkaline Filter: This is the 5th-9th stage of the filtration process. It’s not even filtration either. This stage adds the minerals that the reverse osmosis section removed from the water. These minerals include calcium and magnesium. It also adds oxygen and antioxidants.

Post-Carbon Filter: The final step is the post-carbon filter. It just removes any residual chlorine odor or taste from the water.


The Express ROALK10DCG is an efficient unit as it only wastes 2 gallons of water for every 1 gallon of clean water produced. Now, this might shock most people because it wastes 2 gallons of water. However, this is quite the accomplishment in the reverse osmosis industry.

The threshold for efficiency is 4 gallons per 1 gallon produced. So 2 gallons is extremely good.

Flow rate is 0.8 gallons per minute (GPM). This is basically the same as a normal faucet, which is quite the accomplishment.


Express Water stands behind their product and offer a 1 year warranty.


Installation is relatively straightforward. It is especially aided by the color coding of the different filter housings. Many homeowners will get confused and place the wrong filter on the housing. That isn’t a problem with this Express Water unit.

Furthermore, they provide the housing wrench. Other than that, you don’t need any tools. Unless you need to drill a hole in your kitchen sink.

Express Water has an in-depth installation manual for this reverse osmosis system.

For visual learners, you can check out this YouTube video.


The only maintenance you need to do is changing out the filters. Thankfully, Express Water built quick connect filters, which makes changing out the filters easy.

Replace the sediment, carbon block, and granulated carbon filters twice per year. Sometimes the sediment filter needs more frequent replacement. The clear housing makes knowing when to replace it easy.

If you have highly chlorinate tap water, then you should replace the carbon filters more frequently. Chlorine really damages the reverse osmosis membrane and that is somewhat expensive to replace.

The other filters should be replaced once per year.

Specs & Dimensions

Filtration Unit: 17.25″ (H) x 15″ (W) x 5″ (D)

Storage Tank: 16″ x 11″ x 11″

Tanks Size: 4 gallons

System Capacity: 100 gallons per day

Water Pressure: 40-80 PSI (depends on the amount of water in the tank)

Contaminants Removed (not an exhaustive list. removes at least 90% of the items listed, but usually more): Algae, aluminum, asbestos, bacteria, barium, calcium, cyanide, fluoride, magnesium, mercury, protozoa, silver, sodium, total volatile organics, zinc.




  • “10 stages” (really 6) of filtration to ensure the purest water.
  • Adds essential minerals to your water.
  • 1 year warranty.
  • Excellent price.


  • Water might have a mineral taste if you let it sit for a while because water sits in the mineralizer.