Your water tank will begin to leak at some point, and once this happens, you will likely need to replace it. Even if the leak is small and seemingly repairable, you should strongly weigh your options. When you do spot a leak, you should repair it immediately. Most water tanks can store up to 60 gallons of water, and all of it can end up seeping on your basement floor. This is something you want to avoid because even a minor leak can cause a significant amount of water damage to your home.