# How often do you REALLY have to change a water filter?
**URL:** https://boards.straightdope.com/t/how-often-do-you-really-have-to-change-a-water-filter/581209
**Category:** Factual Questions
**Created:** [May 8, 2011, 11:31pm UTC](https://boards.straightdope.com/t/how-often-do-you-really-have-to-change-a-water-filter/581209 "2011-05-08T23:31:38Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@araminty](https://boards.straightdope.com/u/araminty)
#### Post date: [May 8, 2011, 11:31pm UTC](https://boards.straightdope.com/t/how-often-do-you-really-have-to-change-a-water-filter/581209/1 "2011-05-08T23:31:38Z")
You know, the kind on the faucet, or built into the pitcher? The manufacturer says every 2 months, but I’m assuming that’s to make me buy more filters…
Should I just wait until I can taste the contaminants in the water again? We have chloramine treated very hard water around here.
---
### Author:  [@thelabdude](https://boards.straightdope.com/u/thelabdude)
#### Post date: [May 9, 2011, 1:24am UTC](https://boards.straightdope.com/t/how-often-do-you-really-have-to-change-a-water-filter/581209/2 "2011-05-09T01:24:17Z")
I think how long a filter lasts largely depends on the incoming water. We have a whole house filter. We use the charcoal taste and odor cartridges. Sometimes it is a month or more before before we notice a pressure drop and sometimes less than a week. That usually is when the water table is high and we get a lot of iron oxide. If you are still getting good water, I would let it go.
---
### Author:  [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)
#### Post date: [May 9, 2011, 2:38am UTC](https://boards.straightdope.com/t/how-often-do-you-really-have-to-change-a-water-filter/581209/3 "2011-05-09T02:38:55Z")
1. Low pressure, the cartridge has filtered out enough material that it has become clogged and severely restricts flow through it.
2. Breakthrough, the cartridge has reached capacity and the material/smell can now travel through the filter.
3. 6 months go by, the filter can begin to physically break down or bacteria could begin to reach dangerous levels. A filter could easily last longer but best health practices dictate 6 months maximum or as recommended by the manufacturer.
Of course as you’ve pointed out the manufactures recommendations time might not reflect the limitations of the filter but their sales goals.