1. Check to see if the tank is pushed snugly into the mop—it should click in place.
2. Next, remove the tank. Are there cracks in the tank? If so, the tank will need to be replaced. You can do so by clicking here: http://www.bissell.com/parts/?sc=part&productid=17074&partid=17384
3. Check the tank cap for leaks (make sure the tank is full of solution first). Make sure the cap screwed on the tank tightly. Are there any cracks in the cap? Does it appear to be leaking? If so, you can replace it by clicking here: http://www.bissell.com/parts/?sc=part&productid=17074&partid=17385
Also, grab a pen and push into the x-shaped valve inside the tip of the cap. If it doesn’t release solution, it will need to be replaced.
4. Is the clear rubber gasket attached to the tip of the cap? If not, look in the base of the mop where the tank sits to see if the gasket is stuck in the hole. If the gasket is detached or damaged, you’ll need to order a new cap (see above link). Make sure to only use BISSELL® formula in the tank. Vinegar and other solutions can cause the gasket, tank, and other parts of the mop to break down.
5. Check if there are any cracks in the base of the unit where the solution tank connects to the mop (pictured below).
7. If the mop still leaks, please call us at 1-800-263-2535, Monday - Friday 8 a.m. to 10 p.m., Saturday 9 a.m. to 8 p.m., or Sunday 10 a.m. to 7 p.m. ET. A representative will be ready and waiting to help you out!