Question:
We are lucky to have pretty good water here in the SF Bay area. When they switchedfrom chlorine to chloramine for disinfection I noticed a more unpleasant odor inthe water than the familiar chlorine, and installed an under-sink filter. Thefilter is a Kenmore with a single 10" cartridge; I have been using the 42-34373"Premium Taste and Odor" cartridge. It is supposed to filter 4500 gallons,typically, and have an initial flow rate of 0.6 GPM.

The replacement advice for the cartridge is 6 months, or whenever the flow ratebecome unacceptable. The first cartridge lasted 6 months with no noticeable dropoff. The next and all succeeding cartridges lasted about 2 months, maybe a fewweeks more at an unacceptably low flow rate.

My question is this. Is there a deliberate wear-out mechanism in there to make mechange the carts more often ? Or perhaps my water has become more dirty and thefilter is simply doing what it is supposed to do ? In either case, I wouldappreciate a less frequent maintenance schedule and a better flow rate too. Anysuggestions ?

Answer: It sounds like you got some gunk in your filter if it plugged upthat quickly. Good think you had the filter, otherwise that gunkcould have ended up in your body.

What I do is put a few filters in series. I put a very, very cheapone up front, and the last one is a fairly expensive taste andsmell filter. That way, the cheap filter takes care of the bulkof the stuff, and the expensive one deals with water that is alreadyfiltered twice, so it lasts a long time.

Understood, but this is just a single filter system. If it turns out that thewater is actually dirty enough that it is clogging the filters then perhaps Ishould add a cheap pre-filter as suggested in the response by John Weeks. Theother alternative would be a less expensive cartridge. These are $14-16 each - notbad if they lasted half a year.

On the subject of dirty water clogging the filter, I tried a less expensiveversion. It was the "Taste and Odor" cartridge, not the premium version. The labelclaimed a particle size capture of something like 25 microns compared to the 10microns of the premium version. Simple logic would suggest that it might lastlonger. But in fact it also was rated for lower lifetime, only 3000 gallonscompared to 4500 gallons. Sure enough, the flow through it deteriorated in shortorder.