replaces change your water filter https://www.brita.com/water-pitcher-support/#faq-2 https://www.brita.com/water-pitcher-support/#faq-2 sieve and mesh system Brita: User's Guide every 40 gallons https://www.brita.com/water-pitcher-support/ Brita reduce chlorine and remove cadmium and mercury listing of impurities Brita suggests https://www.brita.com/water-pitcher-support/#faq-2 https://www.brita.com/water-pitcher-support/#faq-2 every 40 gallons by the brand Brita suggests