Cement, a mineral element of concrete, functions as a binder to hold rocks, sand and water together to form a hard, porous substrate. When water leaks or drips from the base of flower pots, minerals from your water leave behind spots and stains to the concrete. If any chemicals are from the water, then they can also stain the concrete. In most cases, a somewhat acidic cleaner combined with some scrubbing may get rid of these stains without etching concrete.
Fill a spray bottle with equal parts white vinegar and water.
Spray the water stains thoroughly using the vinegar solution, saturating them fully. Let it sit for five minutes.
Scrub the stained areas with a nylon-bristled scrub brush to remove the stains. Spray more vinegar alternative if it dried up.
Rinse the concrete using plain water by means of a bucket or garden hose. Allow it to air dry, and repeat the process again if any stains remain.