The invention relates to a combined water basin capable of facilitating cleaning of a mop. The combined water basin comprises a water basin body, a water collecting basin, a cleaning basin and a main discharge pipe, wherein the water collecting basin comprises an outer basin body and an inner basin body arranged in the outer basin body; the tops of the inner basin body and the outer basin body are fixed on the bottom surface of the water basin body; the upper part of the side wall of the inner basin body is provided with a plurality of overflow holes; an overflow circulation space is formed between the inner basin body and the outer basin body and is communicated with the main discharge pipe by virtue of an overflow output pipe; the inner cavity of the water basin body is communicated with that of the inner basin body by virtue of a first auxiliary discharge pipe; the top of the cleaning basin is slidably connected with the bottom surface of the outer basin body; the inner cavity of the inner basin body is communicated with that of the cleaning basin by virtue of a second auxiliary discharge pipe; the second auxiliary discharge pipe is provided with a first control valve; the inner cavity of the washing basin is communicated with the main discharge pipe by virtue of a sewage output pipe; and the sewage output pipe is provided with a second control valve. The combined water basin is capable of improving the space utilization ratio of a toilet, saving water resources and lowering the living cost, and is convenient to use.