Abstract Water lettuce (Pistia stratiots) was utilized for rhizofiltration of water containing 5 to 20 mg Cd L^-1 in a water culture system with a 5-L pot capacity. The contact time for the treatments was one, two, and three weeks. The weight of plant growth was recorded for different Cd concentrations ranging from 0 to 20 mg Cd L^-1 without citric acid (CA) addition, which resulted in the following values: 21.05, 14.38, 12.19, 10.29, and 7.41. Cd removal was observed for all Cd treatments without the use of CA. The average removal of Cd was recorded as 384.83, 485.01, 562.50, and 619.87 µg Cd pot^-1 for treatments of 5, 10, 15, and 20 mg pot^-1, respectively. The corresponding removals via root uptake were 71.80, 92.14, 116.37, and 134.93 µg pot^-1, respectively. The Cd concentration in shoots varied from 25 to 80 µg Cd g^-1, while in roots, it ranged from 38 to 97 µg Cd g^-1 dry matter. The addition of CA to water increased Cd removal due to its chelating effect, which made the metal more easily available. Untreated plants (without CA) showed low Cd levels, whereas CA-treated plants demonstrated the capability of extracting significant amounts of Cd. The chelating effect of CA on the metal increased its availability to water lettuce (Pistia stratiots).