What is Reverse Osmosis and what types of contaminants does the Reverse Osmosis system remove?

Posted by Max Water on 7/12/2023
What is Reverse Osmosis and what types of contaminants does the Reverse Osmosis system remove?
What is Reverse Osmosis and what types of contaminants does the Reverse Osmosis system remove?

About Reverse Osmosis

Reverse Osmosis (RO) water purification systems can reduce and eliminate TDS‡ like salts and minerals from your drinking water. With the increase of pollution, inorganic minerals and chemicals are getting into our water supply.

Our body's cells reject these contaminants, leaving dissolved inorganic substances (acid crystals & minerals deposits) throughout the body. This accumulation of debris creates more work and trouble for the body, such as arthritis in joints, gallstones, kidney stones, and mineral deposits in artery walls. Organically bound minerals, found in our live foods such as fruits and vegetables, are considered soluble, which means the body absorbs them easily into the cells. One glass of freshly squeezed orange juice would be higher in minerals than 30 gallons of untreated raw water.

RO Rejection Rate

Normally 5-stage Reverse osmosis systems can remove/reduce the following list of contaminants:

RO system contaminants

Simple Steps To Select The Right Reverse Osmosis For Your Home

Are You On City Water?


Always add a leak detector to protect your property from potential water damages 105954 and add a pressure control valve if your incoming city water pressure is higher than 70 PSI to protect your RO system from damages.

  • First, check if you have a good incoming city water pressure 55PSI to 75PSI. Recommended to add a booster pump if the pressure is lower than 50PSI.
  • Add a pressure limit valve if your city water pressure is higher than 75PSI 105229, or 105187.
  • Don't add a pressure limit valve after the booster pump, as the booster pump pressure never damage the system or the membrane even when it reaches 110 PSI because the booster flow is limited to 0.9 to 3 LPM depending on the membrane and booster pump you get from the residential range) BUT the city's high pressure damage the system ASV and the membrane when it reached 80 PSI.
Water pH LevelsBeverage pH Levels
Tap Water = 6-8Soda = 2.5
RO Water = 5-7.5Coffee = 4
Mineral Water = 7.4-9Beer = 4.5

With tap water the PH is between 6 to 8, Reverse Osmosis system water drops pH to 5 to 7. If pH is an important factor to you which mostly is yes, you may want to consider adding a PH alkaline filter to rebalance the RO drinking quality 104051 or add our recommended Mix Alkaline Mineral filter 5in1 104185.

The average family of 5 consume about 1- 2 gallons every day including tea, coffee, and cooking. If you are thinking of buying an RO/DI System, consider the size of your aquariums and how often you need to change the water in your tank(s)

Are You On Well Water?

Most well water pumps are designed to work between 40 to 60 PSI, however, there is a 90% chance that your RO system will not work properly without adding a reverse osmosis booster pump, especially if you have a water softener or any other whole house water filtration system, which all reduce the entire home pressure and eventually they will affect the pressure to the reverse osmosis inlet.

In some cases, the home water pressure will be less than 40 PSI, and such a low pressure is not enough to operate the RO system under normal conditions. Sometimes the system works well for 1 or 2 months and then problems will start showing up when the reverse osmosis pre-filters start clogging with dirt and causing the entire pressure drop inside the RO system.

To make the water potable add a 0.5 to 1 LPM UV Sterilizer 105551 to kill any well water bacteria if you do not have a central whole house UV system.


If the well water has hydrogen sulfide as a reaction of iron, sulfur, manganese present in water, and it is not treated prior to the RO system, it can cause problems with slime and build-up on the RO membranes if hydrogen sulfide oxidizes and/or there are sulfur bacteria present. RO membranes by themselves do not remove odor. You should add an iron filter before the Reverse Osmosis system.

Also if you Reverse osmosis supplied with a booster pump, presenting iron in water will damage your booster, iron will clog the booster pump nozzles, and damage the baring and the booster start leaking in a very short time all depending on the iron level in your main incoming water, so to avoid the short time failer to your RO system, consider adding a main iron system before the RO system to protect your system. Add 103458 or select the whole house system from this link .

We Build Custom RO Systems

Can't find a model that meets your specific application? We can custom-build a system to meet your needs. Reverse Osmosis Water and Growing Great Cannabis.

You can pick:

  • Reverse Osmosis System
  • Reverse Osmosis System
  • Reverse Osmosis System
  • Reverse Osmosis System
  • Reverse Osmosis System
  • Reverse Osmosis System

Before You Start

  • Shut off the system's main incoming water supply (normally you'll have either the feed water adapter ball valve or the self-piercing saddle valve).
  • Open the counter-top RO Faucet to drain all the water out of the storage tank, you can save the tank water in a container for use while the system is flushing.
  • Turn off the holding tank ball valve to stop water from entering the tank during filter change.

Changing the Pre-Filters

  • Open the pre-filter housings by using a housing wrench by unscrewing them clockwise.
  • Throw away the used filter, clean the inside of each filter housing by rinsing them or washing them with a mild dish soap solution.
  • Remove all the wrappings from the new filters & place them inside the filter housings.
  • Make sure that the O-Rings are placed inside the filter housings groove. You must change the O ring every year to a maximum of 2 years to avoid and leaking problems.
  • Hand tightens the housing back into place by turning it counter-clockwise. Keep the housing upright to prevent the O-ring from slipping or from damaging the filter casing.
  • Make sure all the housings are tightly fitted, gently tightening the housing wrench.

Changing the RO Membrane

  • Disconnect the red tube from the fitting on the cap of the membrane housing.
  • Open the membrane housing cap (turn the cap counter-clockwise while holding the housing with your other hand).
  • Pull the used membrane out (you may need to use pliers) and clean the inside of the housing.
  • Insert the new membrane into the housing (double O-ring on the membrane end goes first inside the housing).

Restarting and Flushing the System

  • Turn on the main water supply and storage tank ball valves.
  • Check for any leaks, if there is a leak, tighten the housing a little more (don't apply too much pressure). If it still keeps leaking, shut off the mainline and tank ball valve, then open the filter housing. Check if part of the O-ring is sitting out of the groove. Flip the O-ring over and re-install the housing, recheck for leaks.
  • You must drain the first tank of water after restarting the system. This usually takes 2 hours or less to fill one tank if you have a 50GPD membrane and one hour or less for 100GPD.

Disposing of used/old filters

  • You must dispose of used/old filters in the garbage. Water filters are not recycle-friendly and must be put in the black bin/garbage.

Changing the Inline Post Filters

  • Open the 2 fittings on the polishing inline carbon filter and discard the old filter.
  • Re-apply 6 to 8 rounds of Teflon tape to the fittings and screw them back on the new filter. Note: Make sure to install the new polishing filter with the right flow direction. Please follow the same process if you have another alkaline, mineral, or DI filter in the 6th stage of your system.