When do I need to replace the filter? I last used it 5 years ago.

The filter works until it doesn't pump with easy effort: 1 Liter of water or when newer, 1 & 1/2 liter per minute.

If it gets hard to pump and output slows down. 1. check the pre-filter to make sure it is not clogged with small debris (best clean is with a toothbrush). 2. Pull off the small clip that keeps the pump handle in place and see if the rubber O-ring still looks greasy. If it looks dry: grease it with the small container of silicon lube provided: that should improve performance. 3. Unscrew the filter cartridge and see if the pleated glass-fiber filter looks clogged with dirt. If it does: clean it by shaking it around in water or under a faucet.

If the Hiker pumps easy and quick: the only other problem is the activated charcoal inside the filter. It is very stable (inert) until you pump water through the filter------and then it lasts about 6 months in use. When it is gone: water won't taste as fresh, since the charcoal takes out impurities and organic chemicals. The major reason for the charcoal is: it also removes herbicides and pesticides from water (which may cause cancer).

When the charcoal is used up, if you don't mind the different taste or don't pump water below agriculture or industry----no problem.

I've got a fishing buddy in central Idaho who has had the same Hiker and Hiker filter since 1996. I told him all this a few years back and he said "I only filter water above the farmers and it tastes fine to me!"

If you agree----keep using your 5 year old filter cartridge. If not: buy a new one!
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