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Knowing your RO membrane’s lifespan is vital if you want to keep your reverse osmosis system in good shape.
This article details the average life of RO membranes and the various factors affecting it.
The average lifespan of an RO membrane is 2 to 5 years, depending on certain factors as discussed below.
Most reverse osmosis membranes are manufactured and shipped in dry. They have an indefinite shelf life as long as you store them properly and keep them dry.
RO membranes are best stored in a cool, dry place away from direct sunlight. The storage limits are 40-95°F (5-35°C).
Again, several factors affect an RO membranes’ lifespan. And some membranes will last longer than others, based on the water quality and how they’re maintained.
But generally, you should replace an RO membrane every 2 to 5 years. Most manufacturers provide specific instructions on how often to replace.
There are tell-tale signs to look out for that tell you when your RO membrane needs to be replaced. Let’s get into some of them:
A common warning that your RO membrane is bad and needs changing is a drop in output water quality. If you notice a general decline in your water’s quality in terms of color, odor, and taste, then something is wrong. These sudden changes in your water quality are often caused by sediments or scale clogging up the RO membrane, which means it’s time to replace it.
Another sign you need to change your RO membrane is a drop in output water flow. Water flow typically drops when the membrane has fouled. So if you notice a drop in flow, it’s probably time to get a new membrane.
If your RO system runs continuously, that could be a sign of a clogged membrane, too. It runs continuously because the storage tank does not fill properly. When this happens, it’s time to change the membrane.
An increase in filtered water TDS definitely indicates that your RO membrane is no longer working as it should. Thus, routinely measuring the TDS level in your RO water can help you stay aware of your membrane’s current state.
Manufacturers usually recommend dates for changing filters and RO membranes. So the system manual is an excellent place to start if you need help determining when to change your RO membrane.
Sediment pre-filters are present in all reverse osmosis systems. They trap sediments and other debris and protect the RO membrane from getting clogged too soon. Sediment pre-filters should be changed every 6-12 months.
Carbon pre-filters are in stage 2 (and sometimes 3) of an RO system. They remove chemicals like chlorine and its disinfection byproducts. They also remove VOCs all of which can cause damage to an RO membrane.
Carbon pre-filters should be replaced every 6-12 months.
Carbon post-filters are found at stage 4 or 5 of the RO system. They give the water a final polishing touch. They should be changed every 12 months.
The best way to ascertain the performance of your RO membrane is by measuring the total dissolved solids (TDS) levels in the permeate water using a TDS meter.
To do this, test the TDS of the raw water, then test the filtered RO water.
This formula gives you the TDS rejection rate:
Rejection rate in % = (TDS of raw water – TDS of RO water) / TDS of raw water x 100
If the rejection rate is lower than 80%, your RO membrane isn’t performing well, and it’s time to change it.
A reverse osmosis system will last 10 to 15 years with proper maintenance (and changing of parts when due).
If you have any questions about reverse osmosis membrane life please don’t hesitate to leave a comment below!
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