How Often Should Reverse Osmosis Filters Be Changed?
Reverse osmosis systems have filter cartridges that need to be changed (see our images below). The frequency for these changes depends on the specific model, the water it's being used to purify, and the cartridge we're talking about. Let's have a quick look at a couple of common reverse osmosis system configurations:
Generally speaking, the prefilters on an RO system are changed once or twice per year, and the membrane is changed every 2 - 3 years. For RO systems that have a post-filter, this is changed once per year
The Change Schedule Depends On Multiple Factors:
The frequency at which RO filters need to be changed depends on several important factors:
Water Source
If your water source is not chlorinated you likely only need to change your pre-filters once per year since you don't have the chlorine that would otherwise consume the carbon pre-filter(s). If your non-chlorinated supply is heavy on sediment, you may need to change the sediment filter more than once per year if you're getting slow RO system recovery.
Water Consumption
Using a lot of water will increase the rate at which all of the RO system filter cartridges need to be changed. This is especially true if you're using your RO water for non-drinking applications such as watering plants, washing windows, or for hobbies like brewing or aquariums.
Symptoms That Your Filters Need To Be Changed:
There are several symptoms that suggest that some or all of your reverse osmosis system filter cartridges need to be changed:
Recovery Rate
This is the speed at which the RO tank refills after being depleted. If this starts to take an excessively long time, it is usually because one or more filters need to be replaced. Here's the order in which we suggest you change them to see which one is the culprit:
- sediment pre-filter
- carbon pre-filter
- 2nd carbon pre-filter (if one is present)
- membrane
Low Tank Volume
If your RO system dispenses only a small amount of water before the tank is depleted, it's likely that the membrane is clogged and needs to be replaced.
RO Systems with "sump" style filter housings
These systems usually have two or three filter housings that hang vertically from the main system manifold. The RO membrane is mounted horizontally and often there's a "post filter" that is piggy-backed on the membrane:
RO Systems with Twist Lock Filter Cartridges:
These systems usually have three, four, or five cartridges that all hang down from the main manifold. The pre-filters, membrane, and post-filter are each contained in their integrated housing and are removed from the manifold by turning them and pulling them:
