How to Check Battery Water Level

by Dan Ferrell
Jupiterimages/ Images

Your vehicle uses the battery to store and produce electricity to operate the different electrical systems. The water, or electrolyte, inside the battery helps in the electrochemical reaction to store this energy in the battery plates. Thus, as part of your car battery maintenance schedule, you should check the battery water level periodically to ensure proper battery operation and engine performance. You can check the battery without special tools and, if necessary, bring the water to the correct level in a few minutes at home.

Step 1

Prepare a solution of one tablespoon of baking soda and about eight ounces of warm water using a foam cup.

Step 2

Open the hood of your car and put on a pair of latex gloves and safety glasses to keep battery acid off your hands and eyes during the inspection procedure.

Step 3

Apply the solution to the top of the battery with a soft brush to remove dust, grease and acid residue. Wipe clean the battery with a paper towel. Cleaning the battery will prevent contamination of the water inside the battery during inspection and neutralize any acid residue.

Step 4

Pry off the vent caps from the top of the battery with a standard screwdriver and carefully wipe clean any dirt around the battery filler holes with a clean paper towel.

Step 5

Look through the battery filler holes and check that the water level covers the top of the battery plates and separators. If necessary, use a flashlight to help you see the actual water level. If your battery has fill rings, which are basically an extension of the filler hole walls and are used as a level indicator, make sure the water level reaches the bottom of the fill rings.

Step 6

Add distilled water to every cell or battery filler hole to cover the top of the battery plates and separators, or to bring the level up to the bottom of the fill rings, if necessary.

Replace the vent caps on the battery, throw away the latex gloves and close the hood.


  • Many vehicles now use maintenance-free batteries, which do not require inspection of the water level. They lack removable filler caps and can operate for years without losing the electrolyte inside.

Items you will need

  • Baking soda
  • Warm water
  • Foam cup
  • Pair of latex gloves
  • Safety glasses
  • Soft brush
  • Paper towels
  • Standard screwdriver
  • Flashlight, if necessary
  • Distilled water, if necessary

More Articles