How and When to Clean Your Plastic Storage Tank

How and When to Clean Your Plastic Storage Tank

Custom-modified aboveground industrial water storage tanks from BARR Plastics

Proper care and maintenance of your storage tank is crucial to keeping it sanitary long-term.

If you're using your collection tank for potable water, you'll require more frequent and more intense cleaning to avoid sickness or health issues. The colour of your tank will also be a determinant in how frequently it requires a cleaning - translucent or lighter coloured tanks allow more sunlight into the tank, encouraging quicker algae growth than dark green or black tanks.

How often should you be cleaning your tank?

This will depend on the size of your storage tank, as well as how much algae or silt has accumulated since you first started using the tank or since the last time you cleaned it. Cleaning your tank 1-2 times per year should be sufficient for non-potable uses. This is especially important even if you're only utilizing your water collection for vehicle washing, irrigation, or toilets/laundry; you'll still want to ensure that you're keeping your tank sanitary and avoid a large accumulation of bacteria, algae, sludge, and other undesirable debris.

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For potable water tanks, you'll want to look into cleaning it 2-3 times per year. In most cases, you'll be able to take care of the cleaning process yourself and won't need to hire a professional.

It's also important to note that for potable tanks, you'll want to have your system inspected on a semi-regular basis. This can keep you safe from dangerous contaminants and keep your water safe enough to consume.

You'll also want to inspect your system if it hasn't been used recently (and you're looking to use it again) or if it hasn't been drained in some time.

What should you use to clean out your storage tank?

Most of the items you'll need to clean out your tank are readily available:

• Water
• Liquid bleach
• Gloves
• Eye protection
• Scrubbing tool or mop (with sponge/scrubber head)
• Pressure washer (optional)
• Pump or wet vacuum (optional)
• Chlorine test strips

Follow recommended guidelines for mixing bleach and water for sanitization purposes. Generally, about one tablespoon of bleach per gallon (3.7 L) of water will be sufficient for cleaning but will still be safe.

Depending on the size of the tank, scrubbing and rinsing the interior with bleach solution will be enough to ensure proper sanitization. For larger tanks, you might want to use a pressure washer to make the cleaning process quicker and/or use a pump or wet vac to assist with draining the tank. For small capacity tanks, this likely won't be necessary.

What's the best process for cleaning your tank?

1. Fully drain your water tank. If you're working with a large tank, make sure that you're draining into a location that can realistically handle a large amount of water. Additionally, you may want to use the pump or wet vac at this point to get rid of excess water that won't fully drain. If you're cleaning a small tank, this shouldn't be an issue.
2. Scrub the interior walls or pressure wash. Your goal here is to remove as much of the built-up grime and algae as possible. If you're having trouble, using a mild abrasive, like baking soda, can help break down the debris. Larger tanks may require a long-handled mop with a sponge head or a pressure washer in order to reach the top and corners. Be diligent during this process - the tank should look almost-new by the time you're finished with the scrubbing process.
3. Rinse and drain the tank. Here you'll want to get rid of the cleaning materials and debris you've successfully removed from the walls of the tank. Try to be thorough in this stage and get rid of as much of the dirty water as possible.
4. Clean the interior with bleach solution. As previously mentioned, about 1 tablespoon of bleach per gallon of water is an appropriate mixture. This is also where your hand and eye protection will come in handy - you'll want to use gloves and glasses or goggles during this phase in the cleaning process. This involves scrubbing the walls with the solution and ensuring that you've covered as much of the tank as possible.
5. Leave the solution for 2 hours. Some bacteria and other microbial contaminants can be difficult to kill off - letting the bleach mixture sit will allow it to sufficiently kill any stubborn contaminants.
6. Rinse the tank out again. This time, you'll want to be as thorough as possible. This is absolutely crucial for safety, especially if this is a drinking water container. A quick way to check if you've sufficiently rinsed is to look for a soapy quality or bubbles - when the water is running clear, you've likely thoroughly rinsed out all of the bleach. In addition to safety concerns, you'll want to look for a secure place to rinse as the bleach solution will harm wildlife if emptied into a stream or other body of water. You'll also want to avoid any area near to where a septic system may be buried.
7. Test the water and measure chlorine levels. This is something you'll want to do even if you're certain that you've rinsed all of the bleach from the tank. You'll need to do this before fully re-filling your tank and using your system again. You need to be absolutely sure that your freshly cleaned tank doesn't still contain some amount of bleach.
8. Rinse again if necessary. If you've tested your water and the chlorine levels are too high, you'll need to continue rinsing until you've reached a safe level. Again, look for bleach bubbles and be sure to use hot water if possible at some point during the rinsing process.

Looking for more advice on water tank maintenance? Need additions to your inventory or replacements for your residential rainwater harvesting system? We're always happy to help! Call or email us today to talk to a specialist to get advice. If you just need to browse, take a look at our website HERE to see our full product lines and accessories.

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