"When should I change my filter???"
According to the manufacturer, these filters will work for about 1 year (1000 gallons). However, we recommend replacing that you replace your filters every 6 to 9 months for peak performance. Carbon filters absorb chemicals like a sponge, and once saturated the carbon can no longer absorb any more chemicals and must be disposed of. For other replacement filters, click here.

"The WLCS 1000 has an electronic monitor. Why not just replace the filters when the monitor tells me to???"
When it comes to drinking water, it's better to be safe and overly cautious. Even if the monitor does not let you know it's time to change the filters, you should replace your filters every six to nine months, or at the very least, replace your filters once a year.