HVAC & PLUMBING BLOG

reverse osmosis system waiting to be installed

Reverse Osmosis System – Consider Upgrading

Plastic water bottles aren’t the best option even in the best of times. They are more expensive and while recyclable, they aren’t fully biodegradable and end up polluting the waterways and soil of the globe. Times of crisis can lead to shortages and if you rely on bottled water, you might find yourself completely dry. Upgrading to a reverse osmosis system can keep your water needs met.

Reverse Osmosis, Forward Thinking

What is Reverse Osmosis?

Reverse osmosis processes unfiltered water into filtered drinking water. Using a number of different filters, it removes sediment, chlorine, and other contaminants from water making it safer to drink.

How Does Reverse Osmosis Work?

The feeding water line is pushed with pressure through a semipermeable membrane. The unfiltered water line has more contaminants in it, when this water is pressed against the membrane, the clean water is pushed through the membrane while the contaminants are blocked. There are anywhere from 3 to 5 different filtration stages in an RO system.

Every reverse osmosis system includes one, if not multiple, of each of these filters:

  • Semi-permeable membrane: this removes up to 98% of total dissolved solids
  • Sediment filter: the sediment filter removes dust, dirt, and rust particles (and more)
  • Carbon filter: removes chlorine, volatile organic compounds, and other contaminants that influence the taste, color, and odor of water.

Filters can be either called a pre- or post-filter, depending on whether the water reaches the filter before or after the membrane.

basic diagram of water filtration system
A basic diagram of water filtration.

Here’s How the RO System Works

  1. The water goes through prefiltration. This is the carbon and sediment filters removing the larger contaminants that can clog the membrane.
  2. The water then passes through the RO membrane where the most minute, dissolved particles are filtered from the water.
  3. After passing through the membrane, the water is stored in a storage tank. The RO system continues to run until the tank is full, then it shuts off.
  4. When you want the drinking water, the water flows from the tank through a postfilter to ensure the water is as clean as possible before reaching your faucet.

Benefits of Using a Reverse Osmosis System

RO systems provide a few key benefits

  • Better Taste

Water that has been filtered through an RO system has had contaminants that cause odor and taste problems removed, giving the cleanest drinking water.

  • Saves Money

While an RO system requires an initial investment to set up, once it’s going you can stop purchasing cases of wasteful plastic bottled water! Enjoy better quality water for less!

  • Easy to Maintain

RO systems have few moving parts and are also made with replaceable components so servicing and cleaning go lightning fast.

  • Good for You!

RO systems remove more than just sediment from the water! They filter out nitrates, pesticides, sulfates, and more, to give you the cleanest drink of water.

The Basic Parts of an RO System

An RO system is made up of the following basic lines, filters, valves, etc.

Cold Water Supply Line: While not technically a part of the RO system proper, it is the water source for the RO system, so we’ll include it here.

Cold Water Line Valve: Valve that connects the water supply line to the inlet side of the RO pre-filter. 

Pre-Filter(s): The first filter(s) that the water first passes through in order to protect the RO membranes by removing larger contaminants like sand, dirt, and other sediments that could clog the system. Carbon filters may also be present (to remove chlorine, which can damage the RO membranes).

Reverse Osmosis Membrane: The RO membrane is what makes the system what it is. Semipermeable, it removes a wide number of contaminants, both aesthetic and health-related. 

Storage Tank: After the membrane, the water passes into the storage tank. A standard RO storage tank holds from 2 – 4 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full. The typical under counter Reverse Osmosis tank is 12 inches in diameter and 15 inches tall.

Post filter(s): After the water leaves the RO storage tank, but before going to the RO faucet, the treated water goes through a final “post-filter”. The post-filter is usually a carbon filter. Any remaining tastes or odors are removed from the product water by post-filtration “polishing” filter.

Automatic Shut Off Valve: To conserve water, the RO system has an automatic shut off valve. When the storage tank is full, the automatic shut off valve closes to stop any more water from entering the membrane and blocks flow to the drain. Once water is drawn from the RO faucet, the pressure in the tank drops; the shut off valve then opens to send the drinking water through the membrane while the contaminated wastewater is diverted down the drain.

Check Valve: A check valve is located in the outlet end of the RO membrane housing. The check valve prevents the backward flow of treated water from the RO storage tank. A backward flow could rupture the RO membrane.

Flow Restrictor: Water flowing through the RO membrane is regulated by a flow restrictor. There are many different styles of flow controls, but their common purpose is to maintain the flow rate required to obtain the highest quality drinking water (based on the gallon capacity of the membrane). The flow restrictor also helps maintain pressure on the inlet side of the membrane. Without the additional pressure from the flow control, very little drinking water would be produced because all the incoming water would take the path of least resistance and simply flow down the drain line. The flow control is most often located in the RO drain line tubing.

Faucet: The RO unit uses its own faucet, which is usually installed on the kitchen sink. Some areas have plumbing regulations requiring an air gap faucet, but non-air gap models are more common.

Drain line: This line runs from the outlet end of the Reverse Osmosis membrane housing to the drain. The drain line is used to dispose of the wastewater containing the impurities and contaminants that have been filtered out by the reverse osmosis membrane.

Reverse osmosis systems are incredible pieces of plumbing power, giving you the best drink of water yet, and costing you pennies compared to the same amount of bottled water. Ready to make the change? Reach out the ACE Home Services today and get your new RO system ready to go!