Buying and installing a Reverse Osmosis Purification Unit is a great first step in providing clean and healthy drinking water for you and your family. Most people have a Reverse Osmosis Purification Unit in their homes because they understand how crucial it is to protect themselves from drinking toxic water pollutants. If you want to maintain the freshness coming from your faucet, regular maintenance is crucial! A unit that’s well maintained can last between 10 – 15 years, fail to do so and you may end up with contaminated water.
The time until you need to change the filter is dependent on the quality of your water, as well as how much water you’re using. You may not notice that you need to do this, but it is a good practice. When you leave an old filter in the system for longer than that, you run the risk of having sediment flow past the filter because it can’t hold any more debris.
The following is a guide for maintaining the functionality of your Reverse Osmosis Purification System.
What Will Happen If I Don’t Perform Regular Maintenance?
The simplest way you can guarantee filtered water is coming from your faucet is by replacing the filter. Over the duration of a filter’s life, captured sediment accumulates quickly.
If you do not change the filters and membrane as required, your system will become clogged and will produce less and less water also causing higher waste water production. This decrease in water production is a warning sign that your filters need to be changed. Eventually, your system will stop producing water altogether.
An Reverse Osmosis Purification Units effectiveness at providing purified water is depending on filters and membranes being replaced on schedule, as part of an effective preventative maintenance program.
If the water coming from your Reverse Osmosis Purification Unit has developed a bad taste or odor, it could be caused by infrequent use, expired filters or worn–out membranes. These depleted components will need to be replaced more frequently and on a regular schedule.
If you notice that the water from your faucet is flowing slower than usual it could either be dirty filters or the water pressure in the storage tank is not set properly or the storage tank need to be replaced.
While you might not think about this one, harmful organisms can breed in your filter if left for too long. If they breed there, the water that goes through your system will pick up these harmful organisms and spread them throughout your system.
Your filter can break down over time, meaning it will no longer be able to filter out the contaminants in your water. If you don’t change this before too long, these harmful chemicals and organisms could end up back inside of your home – which defeats the whole purpose of having a Reverse Osmosis Purification Unit.
Basic Filter Replacement
A Reverse Osmosis System uses a series of filters and a reverse osmosis membrane to purify water by reducing harmful chemicals and other contaminants. A system can have 5 or more filters, each performing a different function.
The first filter is generally a pre-filter designed to trap dirt, silt, sand, and other sediments. If this filter is not properly maintained it will become clogged, reducing water flow and quality, and adversely affecting the reverse osmosis membrane.
The next 2 filters in line is frequently carbon filters, designed to reduce chlorine and taste and odor. Chlorinated water will damage your reverse osmosis membrane.
Your system’s RO membrane is where the actual reverse osmosis phase takes place. Water is forced through the membrane and pure, RO water comes out the other side. Contaminants are not able to go through the membrane and are redirected down the drain.
To finish off the process, there is generally a carbon polishing filter that removes any remaining taste or odors from the water.
Stage 1 – 5micron Sediment Filter – Average 6 Months.
Stage 2 – GAC / Carbon Filter – Average 6 Months.
Stage 3 – CTO / Carbon Filter – Average 6 Months.
Stage 4 – Reverse Osmosis Membrane – Average 2-3 Years.
Stage 5 – Taste & Odor Filter / Carbon Polishing Filter – Average 12 Months.
Stage – Additional – Minerals Filters / UV Bulb – Average 12 Months.

Why Do I Need To Test My Reverse Osmosis Membrane TDS?
A semipermeable reverse osmosis membrane that is in good condition removes up to 99% of all remaining contaminants from your water. This includes lead, arsenic, fluoride, chromium, 98-99% of waterborne pathogens and much more. TDS drop to almost 0.
Reverse Osmosis Membranes last longer than the various filters, not seldom up to 2 or 3 years, provided that you replace pre-filters according to schedule. In some applications, a new Reverse Osmosis Membrane is required every 1 year.
The safest way to determine if your membrane needs changing is by using a TDS meter. If the rejection of output water TDS drops below 80% it is time for a replacement.
- Measure the TDS of raw feed water by submersing the tester’s probes into a glass of tap water. Record the results.
- Measure the TDS of your RO water by filling a glass with RO water (from RO faucet) and submersing the tester’s probes into the water. Record the results.
- Calculate percent rejection using the following formula:

Example: Tap TDS = 260 ppm RO TDS = 20 ppm Rejection = [(260 – 20) / 260] x 100 = [240/260] x 100 ≈ (.923) x 100 = 92.3
Note: If your Reverse Osmosis System is new or the Membrane has been replaced, do not test the first tank of RO water. The first tank will contain sanitizer and possibly carbon fines from your new filters that will cause a false reading.