How often should I change my water filter?
If you have a carbon Filter (the majority of water filters have a carbon filter), here is my advice on how often to change the filter. For a reverse osmosis (RO) unit changing the filter is a little different, but you still need to change filters regularly – see below.
How often should I change my carbon water filter?
There are four ways you will know it’s time to replace your water filter.
Time or Taste or Look or Flow
Time: In general, replace your filter every six months. This is for normal usage (although I never know what the definition of “normal” is!). Replace the filter more often if you drink a lot of water.
Taste: if your water starts to taste or smell funny, it’s time to change the filter.
Look: if the water is discoloured, or if you see things floating in it, it’s time to change the filter.
Flow: if your flow of hot water through the filter gets slower and slower, it could mean your filter is clogged and it’s time to change it.
How will I remember to change the filter?
Filters with Indicators: this is the easiest method. Some water filters, especially those attached directly to faucets, have indicator strips which change colour when it’s time to change the filter. These indicators may not correspond with the number of calendar months suggested by the manufacturer, but they are usually quite accurate. (Be aware though, that some water filter systems are affected by hot water flowing through the faucet; so be careful when making the switch from passive to active filtering mode).
Bonus tip – you can also use this general reminder service to get an e-mail whenever you need to change your air-conditioning or furnace filter!
Mark it on your calendar: If a water filter is rated to last 6 months, for example, then make a note on your calendar six months from the date you installed the new cartridge. You could also mark the date of installation somewhere near the filter unit itself together with the replacement date.
Do I HAVE to replace my filter at the recommended time?
No. Some water filters perform well even months after their recommended change. Others may not last nearly as long. It depends on:
- How much water you use
- What’s in your water that needs to be filtered out
- The quality of your filter
Since replacement filters can be expensive, you may want to wait until the filter has definitely reached its maximum capacity.
You can have a look at the filter to see how ‘dirty’ it is. You can wash off particles from the surface of the filter to extend its life. You can even back-flush it (normally only once) which will make it last longer. Eventually of course it will become full of gunk and you’ll have to replace it.
Do you have any tips for changing the filter?
- Save the packaging from the last filter – it will have instructions on it, plus you can use the packaging for when you recycle it.
- Have the new filter ready to go when you open the compartment containing the old filter.
- Have a waterproof container (e.g. plastic bag, trashcan) ready to receive the old filter.
- Either use gloves or wash your hands very well after changing the filter.
- After you’ve changed the filter, let some water to run through the filter in order to eliminate left-over contaminants and to prime the new filter. Don’t drink the water which first comes out of the tap after replacing the filter. After a few minutes, the water should be perfectly safe to drink.
- And of course, don’t let that first water go down the drain – use it to water the plants or for cleaning!
How often should I change the filter on a reverse osmosis unit?
There are more components in an RO system, and they need to be changed at different times.
Most Reverse Osmosis Filter Systems say that:
- Pre and post filters should be changed every 6 to 12 months.
- The membrane should be changed every 2-3 years OR if you notice a significant drop in water passing through the reverse osmosis system.
- The O-rings should be changed every other filter change on the pre and post filters and every change on the membrane.
See the tips above for carbon filters – most of them apply to RO units too!
Other interesting articles on water filters: