Should I believe my refrigerator?

September 9, 2006 2:03 PM

Should I believe my refrigerator? I have a refrigerator with a water tap and ice maker. It has a filter that costs about $50 to replace. The filter directions say to do so at least every six months. And a light saying it's time to replace it comes on in about six months.

I use this water, but not a lot. Does anybody know if it is ok to simply change it once a year? And whether the light is simply a six month clock or actually measures something like water flow or filter degradation? I'm tempted to just go by taste, but then I noted in one metafilter discussion someone suggested that for sink type water filters, bacteria starts growing on them in a few weeks.... And, while we're at it, I also use a Pur pitcher filter, that has a little orange thingy that moves around a slot until the filter is expired. And I dutifully replace it then. Is this necessary, or can I just go by taste here too. My tap water is perfectly safe and clean, a little high on minerals and doesn't taste as good as the filtered water. Thanks.

posted by rabbus to home & garden (7 answers total)

I'm no expert, but if your tap water is safe, then all your filters are removing is the minerals. I would think that judging based on taste would be a fine method of determining when to replace the filter.
posted by quin at 2:39 PM on September 9, 2006

As a test you could remove the old filter per directions then put it back in again treating it as new..
That would show if it resets , say, a timer or if the machine is actually measuring something about the filter.
The flow measure does nothing with regard to light or heavy usage so i think that is spurious.

Just a data point.
posted by stuartmm at 2:47 PM on September 9, 2006

Plain carbon filter cartridges should not be used for longer than six months as bacteria may build up, filters which contain silver minimise bacterial growth and can be used for up to 12 months
posted by chrisroberts at 2:47 PM on September 9, 2006

I removed the (expensive) filter from my refrigerator, and then plumbed an in-line filter into the icemaker feed line. The in-line filters are under $10 at Home Depot (if I remember correctly). Anyhow, they're a lot cheaper.
posted by Daddio at 2:53 PM on September 9, 2006

Seconding Daddio. You can get an inline filter for your fridge that installs in the water line, is easy to replace(provided you can get behind your fridge to the line), and is way cheaper.
posted by Mr. Gunn at 2:57 PM on September 9, 2006

...and if you don't get the inline filter, you can buy the cartridges for much less on eBay than at your local retailer. We have a Sears Kenmore fridge. The Whirlpool cartridges are identical to the Kenmore ones.
posted by Robert Angelo at 3:07 PM on September 9, 2006

I agree with you that the critical issue is some combination of bacteria, fungi, or protozoans-- probably bacteria. You could try a little experiment. Next time you replace one, at whatever interval, cut the old one open, with a heavy serrated knife, say, and rub some of the carbon granules between thumb and forefinger. If it feels at all slimy, you have significant numbers of some kind of organism growing there.

On preview, I think what flow tests are actually measuring is the degree of organismal growth, because they do tend to clog things up.
posted by jamjam at 3:29 PM on September 9, 2006