The whole unit will last forever. Each black Berkey Filter filters 3,000 gallons and then needs to be replaced. So ask about how long they have had it and about how many times they fill it per day. Should give you a good estimate on the filter life. Also, make sure they haven’t been running softened water through it as the sodium from that process can ruin the filter elements.

I don’t actually think there are any “gotchas” that come to mind. It’s a pretty simple system where any part of it can be replaced easily.

I’ve had a Big Berkey for about 5 years and it has been one of the best investments I’ve ever made. I’ve done a total filter replacement once. We typically run about two gallons through it a day.

If the unit has been sitting unused and dry for a while I would check the rubber washers to make sure they haven’t dried out. Honestly I would just buy a new set of filters which have new washers included and call it a day.

You won’t be disappointed. These are Awesome.