How to Clean a Water Storage Tank

Keeping your emergency water storage tank clean is essential for maintaining safe, great-tasting water you can rely on. Whether you use a 30-gallon stackable tank, a 55-gallon tank, or a 300-gallon doorway tank, routine cleaning protects your supply from bacteria, sediment, and unwanted odors.

Why Cleaning Your Water Storage Tank Matters

Even food-grade, BPA-free, rotationally molded plastic tanks can develop buildup over time. Cleaning helps prevent:

  • Bacterial growth from stagnant water
  • Algae and film if the tank has been exposed to light
  • Sediment and mineral deposits from fill sources
  • Off-tastes or odors that make the water unpleasant to use

How Often Should You Clean a Water Tank?

infographic showing how often you should clean an emergency water storage tank

A good rule of thumb is:

  • Every 12 months for tanks used solely for emergency storage
  • Every time you rotate out your stored water
  • Immediately, if you notice discoloration, odor, or contamination

Using long-term water treatment drops can extend the lifespan to up to 5 years, but periodic refreshes are still a good idea.

What You’ll Need Before You Start

Safe Cleaning Supplies

  • Unscented household bleach (for sanitizing)
  • Mild dish soap (optional for light cleaning)
  • Clean water for rinsing

Tools for Scrubbing and Rinsing

  • Long-handle brush or soft sponge
  • Hose (preferably lead-free drinking water hose)
  • Access to the tank’s 5" lid for internal cleaning

Step-by-Step Guide: How to Clean a Water Storage Tank

1. Drain and Inspect the Tank

Use the bottom spigot to empty the tank completely—one of the biggest advantages of Emergency Water Tanks is that no pump is required. Remove the lid and check the interior for film, residue, or sediment.

2. Scrub the Interior Walls

Mix a mild soapy solution and scrub all surfaces you can reach. Because your tank is rotationally molded, the walls and corners are equally strong, giving you full scrubbing access without worrying about weak points.

4 steps showing how to clean a storage water tank

3. Sanitize the Tank

Disinfect the tank using a bleach solution:

  • Add 1 teaspoon of unscented bleach per gallon of water inside the tank.
  • Fill enough solution to coat all interior surfaces.
  • Let it sit for 2–4 hours to ensure full sanitization.

4. Rinse Thoroughly and Refill

Drain the sanitizing solution through the spigot, then rinse the tank with clean water until no bleach smell remains. Refill using a potable water hose and, if desired, add approved water treatment drops to extend storage life up to 5 years.

How to Keep Your Tank Clean Longer

  • Store tanks in a cool, shaded area away from sunlight.
  • Use BPA-free, lead-free hoses for filling.
  • Add long-term water treatment to prevent microbial growth.
  • Keep the lid tightly sealed to avoid debris or insects entering.
  • Avoid setting tanks directly on dirt—place them on a clean, level surface.

When It’s Time to Replace Your Tank

Rotationally molded tanks last for many years, but consider replacing if you notice:

  • Cracks or UV damage
  • Leaks in the spigot or bulkhead fitting
  • Persistent odors even after cleaning

If you need a new setup, our 30, 55, and 300 gallon emergency water storage tanks are made in the USA, food-grade, and engineered to last.

Clean tank. Safe water. Real preparedness. Keeping your storage system fresh takes only a little time—and gives you peace of mind when you need it most.

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