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Would you stake your life, right now, on the condition of your equipment?
NEWS | March 6, 2023

M149-Series Water Trailers: Water Tank Cleaning Tips

BLUF: Failure to always keep the water tank clean could result in serious injury or death to personnel.

M149A2 Water Trailer
Photo by Sgt. Christopher Sarratori

This article initially appeared in PS 726, p. 6-7 (May 13).

WARNING: If contents of water tank was other than potable water, the water tank must be flushed out with clean potable water and drained. Do not allow trailer to sit for extended periods of time with any amount of liquid in it. Standing water will result in contamination and food poisoning. KEEP WATER TANK CLEAN AT ALL TIMES. Failure to follow this warning may result in serious injury or death to personnel.

If you’ve read TM 9-2330-267-13&P (Dec 15*), you’ve probably seen this warning. It lets you know it’s not a good idea to wait until the last minute to clean your water trailer’s tank. And it’s not a good idea to leave water in the tank for months at a time!

Cleaning the tank improves the taste of the water and keeps the tank safe to use. The TM says to clean the tank annually or when the medics tell you the tank is contaminated. But why wait? You have to drink the water too!

Here are some PM tips to keep you from drinking slimy, rusty or metallic-tasting water.

Trailer on incline enables water to drain through the drain plug completely.
Trailer on incline enables water to drain through the drain plug completely.

  • When you’re done using the water trailer, empty the tank completely. Water left in the tank causes rust, mineral deposits and algae buildup. Put the trailer on an incline with the rear slightly lower than the front so that all water will drain through the drain plug. Then open the faucets to let out any water still in the pipes.
Closing manhole keeps out dirt, sand and rain.
Closing manhole keeps out dirt, sand and rain.
  • Close the manhole cover tightly when the water trailer is in storage. That keeps out dirt, sand and rain.
  • ​To stop deposit buildup, every three (3) months pour in eight (8) gallons of vinegar, NSN 8950-01-079-3978, and leave it for 5-6 hours. Then empty the tank and flush it with clean water.
  • ​Clean the tank more often during the summer since you’ll be drinking more water then. Make sure you drain the tank completely between uses.​

Rusty Stainless-Steel

If the water from a stainless-steel tank has a rusty, metallic taste, check the weld joints in the tank for rust.

Rust on welded joints can cause metallic taste of water in tank.
Rust on welded joints can cause metallic taste of water in tank.

Scrub away rust with a solution of water and scouring powder, NSN 7930-01-294-1116. Always use a nonmetallic, nylon brush. You can get one with NSN 7920-00-061-0038.

Flush the tank thoroughly with clean water. Scrub it again if you still see rust. You’re done when the rust is gone.

Look at TB MED 577 (May 10), Sanitary Control and Surveillance of Field Water Supplies, for more on cleaning.

* Editor’s Note: The TM date of issue has been updated since this article initially appeared.

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