How to Fix Holes in a Rusty Water Tank

Things You\’ll Need

  • 1 tube of sealant/adhesive for use on metal

  • Caulking gun

  • Wire brush

  • Microfiber cloth

  • Putty knife

  • Metal paint (optional)

  • Paintbrush (optional)

Water towers in a city Water tanks exposed to the elements may rust faster than one inside a building. Image Credit: Jupiterimages/ Images

When you find puddles of water around your water tank, chances are your water tank rusted and ate through the tank material. A temporary fix may hold for weeks or months, giving you enough time to make arrangements to replace the water tank. When you find a rust hole in a traditional metal or steel water tank, using sealant may be the solution.

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Clean the Water Tank

Step 1

Empty the water tank to ensure the space around the leaky hole is dry.

Step 2

Scrub the area around the hole with a wire brush to remove all the rust and clean the space.

Step 3

Wipe the area with a microfiber cloth to ensure all dust particles and rust are removed from the space you will be working in.

Step 4

Recheck the area to make sure you have removed all moisture and dirt before repairing the hole.

Repair the Hole

Step 1

Snip the tip off the sealant, making the hole as large as you need it to be to manage the adhesive easily.

Step 2

Insert the tube of sealant into the caulking gun. Ensure it is snapped securely into place.

Step 3

Dab the sealant around the area until the space is fully covered with the product.

Step 4

Smear the sealant evenly over the affected area with the putty knife.

Step 5

Paint the area over and around the sealant once the product is dry; this is highly recommended if your water tank is located outside as exposure to sunlight and the elements can break down the sealant at a rapid rate. For water tanks inside a building, this step is optional.


Corrosion is the main reason water tanks fail. To reduce the chances of rust eating a hole through your tank in the future, check the tank's anode rod annually and replace it if necessary. The anode rod reduces corrosion of the water tank by taking on the corrosion, keeping the rest of the tank relatively safe from rust. But once the anode rod wears away, the rest of the tank is more susceptible to corrosion and rust holes.

Use a sealant cleaner to remove leftover adhesive on your putty knife.


Sealants and adhesives are generally harmless when proper directions are followed. Read the directions thoroughly that come with the product.

Wear protective goggles and clothing when working with the sealant.

Work in a well-ventilated area.

Thoroughly wash your hands with soap and warm water when you are done with your repair job.