How to Remove Mineral Deposits in a Swamp Cooler

Updated March 23, 2017

Evaporative coolers must be cleaned periodically to prevent the build-up of many mineral deposits. These cooling units, also known as swamp coolers, cool air by blowing it through water-soaked pads. As the water evaporates into the air, it leaves behind mineral deposits that can interfere with the unit's efficiency. The coolers should be cleaned in the spring and checked every month or so during the summer. Cleaning the units is especially important when you are shutting the unit down for the winter. If you wait until next year to clean it, the deposits will have hardened and be more difficult to remove.

Unplug the unit and turn off the water supply.

Remove the cooler's access panel using a screwdriver. The access panel on a window-mounted unit is usually on the side, while the access panel on a roof-mounted unit usually is on the top.

Drain the water from the unit by unscrewing the drain plug.

Examine the evaporative cooler pads for mineral-deposit build-up. If the pads have a heavy mineral build-up, replace them. Clogged pads reduce the efficiency of your cooler. For pads with only a little mineral build-up, turn them around and upside down so the air flows through the opposite side.

Remove mineral deposits from the water tray with a scraper. Clean any mineral deposits you see on any moving parts. Coat any stubborn or hard-to-reach deposits with vinegar. Wipe the deposits away with a rag after letting the vinegar work for about 30 minutes.

Wipe the inside and outside of the unit dry. If you are shutting the unit down for the winter, coat the water tray with a rust-preventing product.


You can extend the life of many synthetic cooler pads by soaking them in a cleaning solution approved for cooler pads. But do not let too many mineral deposits accumulate of the pad or it will be beyond cleaning.

Things You'll Need

  • Screwdriver
  • Vinegar
  • Scraper
  • Rag
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About the Author

Alan Sembera began writing for local newspapers in Texas and Louisiana. His professional career includes stints as a computer tech, information editor and income tax preparer. Sembera now writes full time about business and technology. He holds a Bachelor of Arts in journalism from Texas A&M University.