Water filter systems work by passing water through one or more stages of filtration media which traps contaminants. Types of media can include activated carbon, which removes chemicals like chlorine and compounds that cause taste and odour issues; ion-exchange resins, which can soften water and remove contaminants like lead; and mechanical filters, which physically remove sediment like dirt, rust, sand and microplastics. More advanced water treatment systems may also use technologies like reverse osmosis or UV purification for even greater purity.