It depends on the facts of your case. Generally in “slip and fall” cases like this, the store is liable if employees knew or should have known about the danger and did not take steps to fix it. Thus, if the floor became wet just before the accident and store employees had no time to clean it or post adequate warning signs, the store is likely not liable. But if the floor was wet for a while and employees knew or should have known about it but did not do anything, you have a good case.