How to Protect Your Water Tank from Sunlight

Sunlight, especially its ultraviolet (UV radiation), may be a good disinfectant but it can also degrade plastic. For above-ground polyethylene water tanks, UV exposure can break down the material at a molecular level, leading to tiny cracks that eventually cause leaks and breaches that are difficult and expensive to repair.

To prevent this? Limit the tank’s UV exposure. Options include installing it indoors, burying it, or building a shelter, but even some shaded areas can still receive UV light.

Here are a few more less intuitive, more scientific options for protecting your water tank from sunlight:

•   UV light stabilizers – A good polyethylene tank will be compounded with a UV-light stabilizing resin. While limiting the ultraviolet radiation, these resins help reinforce the structural integrity of the plastic. Over time, UV light stabilizers will eventually lose their protective powers, especially with prolonged sun exposure. Even with built-in protection, storing your tank indoors or under shelter helps extend its life. The effectiveness of the resin may also depend the color of the tank. Darker colored tanks, for example, absorb more heat and sunlight than lighter colored tanks. That results in more expansion and contraction, aging the tank in the process.

•   Paint – Painting a plastic water tank can protect it from the threat of UV radiation. Before painting, you should know the limits of this method. Due to the amount of expansion and contraction that polyethylene can experience, not all paints successfully adhere to it. Some paints will chip or crack, requiring frequent reapplications. Such a project may end up requiring more work than it’s worth. Be sure to buy paint that can expand and contract without cracking, like acrylic paint. A heavier duty paint option is elastomeric paint, which is very flexible and resistant to UV, moisture, and temperature swings.

•   Insulation – Simply wrapping the plastic water tank in some kind of insulating or protective material is another simple way to protect it from sunlight. Be careful – do not simply rely on the foam insulator you use in the winter months to keep the water from freezing. Instead, use radiant barrier insulation: the type of reflective materials used to keep attics cool in the summer. This material is designed to reflect rather than absorb heat. Radiant barrier insulation is a good way to protect polyethylene from UV damage, but it will not protect the water in the tank from getting too hot. 

In most cases, it’s best to employ a combination of protective measures. UV light is everywhere, so while a shelter can help prolong the life of your tank, it may not be enough, especially if you live in a desert climate or a state like Arizona or California. In addition to what you build or install around the tank, you should consider where on a given property you will place it.

Where should I place my water storage tank to limit UV exposure?

The more UV radiation it gets, the shorter the lifespan it will have. Shelters can help limit direct UV exposure, as can the amount of shade a tank receives in a given day from trees, buildings, and other sources.

Another solution is to bury the tank underground. Above-ground tanks are cheaper to install and maintain, but they require a variety of protective measures to keep the forces of nature at bay. Below-ground tanks hold lower temperatures, make more efficient use of space, and are easier to protect from the elements. But they’re very expensive to install and maintain. Often the decision between the two will come down to environmental considerations: 1) How great is this risk of bad weather, vandalism, theft, and UV exposure, and 2) how much financial leeway do you have in minimizing those risks?

Other Considerations for Protecting Water Tanks from Sunlight

Its clear how sunlight weathers polyethylene plastic and what you can do to stave off that process. It’s important to keep these tips in mind when performing basic maintenance tasks. For example, how often you refill or clean the tank also determines the tank’s longevity. Sediment buildup is inevitable, especially for tanks that routinely cycle through water. But the amount of sediment that builds up before the tank is cleaned or pumped can affect the tank’s lifespan, weakening or eroding the plastic wherever it settles.

There’s another trade-off between sunlight and UV protection, and that’s in the growth of algae and bacteria: The more your tank is protected from sunlight, the more often you’ll need to clean and disinfect the interior. Read here to learn how to properly clean your plastic storage tank.

While lighter colored tanks admit more sunlight and prematurely age the plastic in the tank, that light also helps to disinfect the water inside. Darker, more insulated tanks protect the plastic but also provide a more fertile breeding ground for microbial life, increasing the risk of contamination. In most cases, algae and microbial contamination is a greater, more immediate risk than the structural integrity of the tank itself. Whether to get a lighter or darker colored tank depends on individual and environmental factors. Either way, it underscores the importance of routine cleaning in addition to UV protection. 

How can I tell if my water tank is UV stabilized?

Go To Tanks has a large selection of tanks in a number of different sizes, styles, and colors. From water storage to septic systems, Go To Tanks can be installed above or below ground, and always with a level of UV stabilization and protection. Our linear, high-density polyethylene resins can resist cracks and weather significant environmental stress. Such protection allows the tank to withstand years of direct sun exposure.

Every tank needs to be situated and protected according to its environment. The more you do to protect the tank, be it painting, insulating, or building a shelter over it, the longer your tank will last before it needs repairs.

Call 1-877-468-2657 and we’ll help you find a tank that fits your needs.