By Rehan Iqbal
A good quality water filtrations system will keep providing clean, pure water for many years, possibly even a lifetime. However, to ensure that your water is safe and tastes great you need to perform basic maintenance.
Generally, the only regular maintenance required for a water filtration system is replacing the filters. This leaves most people asking: “how often do I need to change my water filters?”. The answer to this question will depend on numerous factors.
How Long Do Water Filters Last?
Every type of water filter has a limited lifespan. How long these filters last depend on a few basic factors:
Because filters are not the same and work under varying conditions, there is no fixed rule as to when you should replace your filters. As a general guideline, each type of filter should last as follows for normal domestic use:
Obviously, high-quality filters will last longer than cheap alternatives. If you want the best quality water and want to get the most from your water filters, make sure you install quality filters from a known brand.
Below we cover in detail some of the the different types of water filters and factors that can affect how long they can last.
When to Replace Water Filters?
If you’re unsure when it’s time to replace your water filters, you should start by consulting the owner’s manual that came with your filtration system. This will give you a good indication of when and how to change the filters.
Meeting the manufacturer system requirements will ensure that your water filter performs optimally. It’s also important to use quality filters. You should replace your old filters with those recommended by the manufacturer.
Generally, water filters need replacing after a predetermined number of gallons. In other words, after you’ve used the amount of filtered water for which the filter was designed. In some circumstances, a filter may not last as long as the manufacturer recommends. Sometimes, they may last longer.
The lifespan of a water filter is determined by:
Not all water filters are the same. For example, a reverse osmosis filtration system usually utilizes several different filters for different stages. Not all the filters in the system will last the same amount of time and the conditions under which they work will also have an effect.
Pre-filters will be become blocked sooner if your water supply has a lot of sediment, dirt, or rust. Similarly, activated carbon filters don’t last as long if your water has high concentrations of chlorine or other chemicals.
While manufacturer specifications are a reasonable guideline as to how often you need to change your water filters, every situation is unique. By observing your water, you may be able to determine when it’s time to change the filters. If you notice any of the following the signs, one or more of the filters in your system may need to be replaced:
Types of Water Filters
Each type of filter has an estimated lifespan. This is based on average water consumption under common conditions. It can be anything from 3 months up to several years, depending on the type of filter. In most cases, your will water filter will last as long as the recommended period.
Since there are many different types of filters, I will be discussing the most common filters in terms of lifespan and why they need to be replaced.
Refrigerator Water Filters
Fresh, filtered water dispensed directly from your refrigerator is really convenient, making these one of the most popular types of water filters. Many people seem to forget that the filter needs to be replaced in order to keep the system working perfectly.
Even if your refrigerator water looks and tastes great, it may not be as pure and healthy as you think. Unseen, odorless contaminants may be lurking without your knowledge.
A refrigerator water filter needs to be replaced every 6 to 12 months. For an average family of four people, refrigerator water filters last about 6 months. In a home with only one or two people, you can expect the filter to last up to a year.
Some refrigerators have an LED light or digital display that informs when it’s time to replace the filter. These devices take the hassle out of knowing how long the filters last.
Activated Carbon Filters
Carbon or charcoal filters are used to remove unwanted or harmful chemicals from the water. They improve the taste and odor of the water as a result. Because many of the chemicals absorbed by activated carbon filters can be toxic, it is imperative to change the filters regularly.
When a carbon filter becomes saturated, harmful chemicals may be released into the water as it passes through the filter cartridge. It is important to check the recommended lifespan of the filters you’re using and replace them timeously. This would be after the stipulated number of gallons or months.
Generally, carbon filters that form part of a reverse osmosis system will last longer. This is because some contaminants are removed during other stages of filtration. Pre-filters reduce the amount of contaminants that can clog a carbon filter.
How Do Activated Carbon Filters Work?
Heat and oxygen are used to increase the surface area of an activated carbon filter. Contaminants are absorbed into the surface of the media. Once the entire area of the carbon surface is saturated, it can no longer absorb contaminants and may even release previously filtered contaminants back into the water.
There are two types of activated carbon media used for water filters:
High-end multi-stage RO water filtration systems generally utilize both granular and pelletized carbon filters. This ensures the highest level of filtration, whilst prolonging filter life.
How Long Do Activated Carbon Filters Last?
Activated carbon filters can last from 2 months up to a year.
Smaller water pitcher carbon filters are only rated for 40 gallons (like Brita standard water filters). For regular family usage, these filters will last about 2 months. Larger pitcher filters are rated for 150 gallons and should last about 6 months. Some can filter up to 350 gallons and could last up to a year.
Carbon filters used in whole house and under sink reverse osmosis systems tend to last about a year. Carbon filters used for some high-end RO systems may last longer.
Sediment in water is common. The term refers to any type of solid matter that is suspended in the water. This includes:
Sediment filters are generally used as a pre-filter, preventing other filters from becoming clogged by debris.
How Do Sediment Filters Work?
Sediment filters are made from a variety of materials including:
As water passes through the filter, particles are trapped in the filtration media. These filters generally capture sediment up to 5 microns in size.
How Long Do Sediment Filters Last?
Sediment filters last for 6 to 12 months. If you notice a drop in water pressure, it’s probably time to replace your sediment filter. Accumulated debris in the filter impedes water flow, causing reduced water pressure.
Well water often has more debris than municipal water. If you obtain your water from a well, your filter will probably need to be replaced more frequently. Essentially, the lifespan of a sediment filter is determined by how much dirt, rust and other solids are in the water.
Reverse Osmosis Filters
A reverse osmosis (RO) water filtration system will use several different types of filters. Each filter is used for a specific stage of filtration. A simple 3-stage RO system will include a pre-filter, RO filter, and activated carbon filter.
An RO water filtration system can have up to 10 stages, which could include
Each filter used in an RO system will need to be replaced when they are no longer effective. The lifespan of these of these filters will differ according to the type of filter and the quality of your water supply.
How Does a Reverse Osmosis Filter Work?
An RO membrane filter is extremely dense, capturing particles as small as 1 micron. This means that they can remove over 90% of all contaminants found in water.
Pressurized water is forced through the membrane. The filtered water is stored in a tank, ready for use on demand. After the water has been filtered, the water pressure is reversed, forcing it back through the filter. This flushes out most of the contaminants into the drain.
Because RO filters remove most of the contaminants from the membrane with each use, they last longer than other types of filters.
How Long Do Reverse Osmosis Filters Last?
Like all water filters, RO filters don’t have a precise lifespan. It will depend mostly on the quality of your water. If an RO filter works harder, it will need to be replaced more frequently. It will also depend on the quality and size of your filter, as well as how much water you use.
Generally, an RO filter lasts for about 2 years. In some cases, this can be as long as 4 years, sometimes longer.
Under Sink Water Filters
Under sink water filters are relatively compact systems that fit into a cabinet under the sink. They usually supply a single faucet at the sink, but additional outlets can be installed for coffee machines and other appliances.
These filtration systems usually have several filters which can include an RO filter and storage tank. More compact systems will have one or two filter cartridges.
A typical under sink filtration system will utilize a pre-filter and one or more carbon filters.
How Long Do Under Sink Filters Last?
For normal household use, an average under sink filter should last for about 6 to 12 months. Under sink RO filters and water alkalizers last for 2 to 4 years.
If you use a lot of filtered water, or your water quality is poor, you may have to replace your under sink water filters more frequently. Low water pressure or cloudy water is usually an indication that that the filters are no longer effective.