There are steps to follow in the correct of proper water measurement for your car battery. You will find out how often you should go and check for your water level and the appropriate measures to take in doing such tasks. Step 1: Make sure that you wear protective clothing when working on your batteries. Wear long sleeves. Learning how to check the battery's water level is an added skill to your car maintenance. If you know how to check the water levels, you can always expect your battery to run smoothly. No. You should never use tap water for your car battery. Tap water may only cause your battery to wear out quickly. It will also cause your battery to work harder and will cause it to. The overfilled battery tends to create more leak as you charged it. The sulphuric content may cause more issues because it is more corrosive. It will eat up everything it comes in contact with.