Water Filter FAQs

Express Water Reverse Osmosis Systems

Water Pressure: How important is water pressure to an RO System?

Water pressure pushes water through the Reverse Osmosis membrane for purification and flushes the rejected solids away. Low water pressure will result in reduced production and premature fouling of the RO membrane. The ideal pressure for operating an RO system is 60 PSI. Pressure below 40 PSI is considered insufficient, and should be increased using a booster pump, which we offer and can guide you through installing. If your PSI is too high we offer Pressure Regulators to reduce your pressure to acceptable levels.
Let us walk you through these options: call us at 1-800-992-8876 or visit expresswater.com

Iron: Will iron hurt an RO System?

Iron will plug an RO membrane, as the membrane is not able to flush iron out. Trace amounts of iron (up to 2 PPM) can be removed by a water softener. If the water contains 1 PPM or less, there is no need for concern as the membrane will not be significantly affected.


Note: This refers to clear water iron, not red iron. You can tell the difference because clear water iron leaves no visible signs, whereas red iron leaves a reddish brown discoloration in toilet bowls, tanks, sinks, and tubs. If red iron is present, steps to remove the iron will have to be taken.

Water Differences and Dissolved Solids: How is RO Water different from tap water? How will I know the RO System is removing Dissolved Solids from my tap water?

The biggest difference from tap water and evidence the system is functioning is in the taste and clarity of the water produced. Cooking, coffee, drinks, and juices made with RO water will taste better. Ice cubes made with RO water are harder, clearer, and last much longer.


Ice Test:
If you take two similar glasses and put ice cubes made with RO water in one and the same number of ice cubes made from tap water in the other, you will notice that it takes longer for the RO ice cubes to melt. When you melt tap water ice cubes you usually see sediments on the bottom of a glass. This doesn’t happen with RO water.


Conductivity Test: Another way of determining the amount of dissolved solids removed from tap water is by using a conductivity meter. This meter measures the conductivity which dissolved solids create in water. The meter will tell you the parts per million of Total Dissolved Solids (TDS). Express Water offers a water sample kit for the testing of a customer's water to determine how the RO Membrane is working. It can also help to determine when to replace the membrane.

Lifespan: How long does the system last? How long does the tank last?

With proper maintenance and average water quality an RO System should last 5-10 years. The water storage tank usually lasts 3-5 years before we recommend replacing it.

My Home: How do I know this system will work in my home?

The first thing you can do is make sure your installation location has enough room for the system (most people install under their kitchen sink). The Reverse Osmosis Unit is 15.75” x 16.25” x 5.25” and the Water Storage Tank is 11” x 16” x 11”.


The next thing you should do is make sure your home’s water pressure will work with the system. The system works with a minimum water pressure of 40 PSI and a maximum of 80 PSI. If your PSI is too high you can purchase a Pressure Regulator to reduce your pressure to acceptable levels. If your PSI is too low you may need a Booster Pump to aid your system.


If you’re not sure if this system will work in your home: let one of our technicians help you figure it out; call us at 1-800-992-8876 - 10am-5pm (Pacific Time) Monday-Friday.

System Life: How long does the system last? How long does the tank last?

With proper maintenance and average water quality an RO System should last 5-10 years. The water storage tank usually lasts 3-5 years before we recommend replacing it.

Tank Capacity: How much water can the Water Storage Tank hold?

The maximum capacity of the standard RO tank is 3.2 gallons. However, the typical tank reaches 2-2.5 gallons. Your Water Storage Tank’s capacity depends on your incoming water pressure. Lower water pressure means the tank will hold less water.