Cold Water Line Valve: This valve fits onto the cold water supply line and has a tube that attaches to the inlet side of the RO pre-filter. It is the water source for the RO system
Pre-Filter(s): This is where the cold water enters first. There may be more than one are most commonly sediment filters.
Reverse Osmosis Membrane: Most commonly this is a spiral wound of CTA (cellulose tri-acetate) or TFC/TFM (thin film composite/material) and this is the central part of the system.
Post Filter: After the RO storage tank, but before the RO faucet, the water goes through the post filter. This is where any remaining tastes and odors are removed by a, generally carbon, filter.
Automatic Shut-off Valve: Designed to conserve water, the RO system will have an automatic shut of valve. When the storage tank is full this valve will stop further water from entering the membrane and will open again when water has been used.
Check Valve: The check valve is located in the outlet end of the RO membrane housing and prevents backward flow that could cause a rupture in the membrane.
Flow Restrictor: The flow restrictor regulates the water flow through the membrane. There are multiple different types of flow restrictors and it helps to obtain the highest quality drinking water.
Storage Tank: The standard RO storage tank holds up to 2.5 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full.
Faucet: The RO unit uses its own faucet, which is usually installed on the kitchen sink. In areas where required by plumbing codes an air-gap faucet is generally used.
Drain Line: This line runs from the outlet end of the Reverse Osmosis membrane housing to the drain. This line is used to dispose of the impurities and contaminants found in the incoming water source.