A Taste of What's Inside
We’ve covered the importance of keeping an emergency water supply, the different types of storage tanks you can use, and the key factors to consider when choosing one. You’re also familiar with the types of contaminants that you might have to deal with. Now it’s time to focus on a critical component of your water storage system: the liner.
By keeping your water from interacting with the material of the storage tank itself, potable water liners prevent contaminants from leaching in and compromising your water’s purity. This chapter will explore the different types of potable water liners, their unique characteristics, and how to choose the right one for your needs. Let’s learn how the right liner can improve your water storage system.
Liner Materials
Potable water liners are made from specialized materials selected for their durability, safety, and ability to prevent contamination. Here’s a look at some of the most common options:
Geomembranes
Reinforced Polyethylene (RPE) is a popular choice for potable water liners. It’s known for its long lifespan and robust performance. Since RPE liners can withstand prolonged exposure to sunlight without degrading, they can last for decades with proper care. In the rare event of damage, RPE liners can be easily repaired with heat welding or patching.
RPE does not rely on plasticizers to maintain flexibility, removing a significant concern about phthalates and other harmful chemical compounds leaching into your water.
While the initial cost of RPE might be slightly higher than some other options, its longevity and ease of installation and repair can make it a more cost-effective choice in the long run, especially compared to sprayed-on liners like epoxy and polyurethane. Custom prefabrication ensures a precise fit, simplifies installation, and reduces labor costs.
Polyvinyl Chloride (PVC) is another common tank liner material, thanks to its easy installation and affordability. PVC liners are available in various grades and thicknesses for different uses and budgets. They’re also flexible and easily conform to different tank shapes. PVC liners are also relatively easy to install, requiring fewer specialized tools and skills than other liner types, especially spray-on liners.
However, be aware that you may encounter some misinformation about the inherent antimicrobial properties of PVC liners. While PVC does have some initial antimicrobial effects due to the release of HCl (hydrochloric acid) during manufacturing, this effect diminishes rapidly. It will not provide advantages for keeping your stored water free of biological contaminants.
More concerning, some PVC liners contain plasticizers to increase the material’s flexibility. However, these plasticizers leach into the water as the material ages and degrades, especially when exposed to UV radiation. Exposure to these plasticizers is closely tied to significant reproductive system issues in both men and women. If you’re storing drinking water, always verify that you’re using plasticizer-free materials.
Other Tank Linings
While geomembranes are a popular and versatile solution for many water storage applications, not all are suitable for every situation. For example, if you have a steel or concrete tank, you might choose a different type of lining to protect the tank from corrosion or other damage.
Epoxy Coatings are a popular liner for steel tanks. Like RPE geomembranes, they directly shield the steel from the corrosive effects of water by keeping the steel from coming into direct contact with it.
Epoxy coatings are also resistant to many types of chemicals that may be present in the water. They can be applied in various thicknesses and are available in formulations compatible with potable water.
However, epoxy coatings can become brittle and are prone to cracking if the tank flexes or expands from thermal changes or ground movement. Epoxy coatings need specialized equipment and expertise for proper application, which can increase installation costs.
Polyurethane Coatings are used to line both steel and concrete tanks. They’re flexible and resistant to abrasion, making them a better option for tanks that may experience some movement or expansion. Like epoxy coatings and RPE liners, polyurethane coatings protect steel tanks from corrosion. They also provide a dependable barrier against potential contaminants in the water.
Since polyurethane coatings are susceptible to degradation from UV exposure, they’re not the best choice for tanks in direct sunlight. Like epoxy, polyurethane coats need specialized equipment and expertise for application. It’s also crucial to ensure that the chosen polyurethane coating is compatible with potable water.
Why Choose Potable Liners (Even for Non-Drinking Water)
You might think, “If I’m not storing water for drinking, why should I care about a potable-grade liner?” It’s a great question, and the answer might surprise you. Even if your immediate plans don’t involve drinking the water, there are several compelling reasons to opt for a potable liner:
Safety First
ANSI/NSF-certified potable liners are guaranteed to meet stringent safety standards that ensure no harmful chemicals can leach into your water. This protection is essential for drinking water and for virtually any other use. After all, using contaminated water to irrigate your garden or water your livestock can have serious consequences. Your plants or animals could absorb those contaminants, damage their health, and end up in your food supply.
Future-Proofing Your Storage
Your water storage needs might change over time. Perhaps you’re currently storing water for irrigation. Still, a drought or emergency could make that water a vital source for drinking. With a potable liner, you have the flexibility to convert stored water to drinking if the need arises. However, keep in mind that additional treatment and disinfection will be necessary to ensure the repurposed water meets drinking water standards, especially if it was initially intended for other purposes.
Putting a Lid on It
The right liner is a crucial element of a successful water storage system. The liner provides a protective barrier between your water and the storage tank, preventing contamination and maintaining water quality and safety. We’ve explored the most common liner materials, including reinforced polyethylene (RPE), polyvinyl chloride (PVC), and spray-on options like epoxy and polyurethane. We’ve also discussed the importance of choosing a liner compatible with your tank material and water source and considering factors like UV resistance and plasticizer use.
In the next chapter, we’ll talk more about choosing the right potable water liner, including discussing the all-important ANSI/NSF 61 certification and how to evaluate different liner options based on your requirements.
