Pool Liner Thickness: 20 Mil vs. 27 Mil vs. 28 Mil vs. 30 Mil

One of the most important decisions you’ll make if you’re thinking about purchasing an inground vinyl liner pool is choosing the right pool liner thickness. While many homeowners focus on liner color and pattern, thickness plays a key role in your pool’s durability, maintenance needs, and long-term costs.

The most common liner thickness options are 20 mil liner, 27 mil liner, 28 mil liner, and 30 mil liner—but the differences between them aren’t always clear.

We have installed hundreds of liner pools over our 25 years of business here at Royal Pools G2 Landscaping. Nowadays, we only install 20 and 27 mil liners, but we love educating all potential pool owners on the options. This guide will break down each option, explain how thickness affects performance, and help you decide which is best for your budget and lifestyle.

Understanding Pool Liner Thickness

The term “mil” refers to one-thousandth of an inch (0.001 inches). For example, a 20 mil liner is 0.020 inches thick, while a 30 mil liner is 0.030 inches thick.  It’s important to note that “mil” is not short for millimeter. Common mistake, don’t feel bad.

Thickness influences how well your liner resists UV damage and general wear. Proper installation, balanced water chemistry, and regular maintenance are key to getting the most out of your vinyl liner pool.

Vinyl pool liners are either embossed or non-embossed. Non-embossed liners are flat across the entire liner, whereas embossed liners have divots. This makes an embossed liner feel squishier and more comfortable.

Embossed liners are affordable and easier to install than non-embossed liners, but the peaks and valleys ultimately make them even more susceptible to tears. If you purchase a 30 mil embossed liner, you wouldn’t get a liner that is truly 30 mils thick. Rather, you’d get a liner that is 30 mils at its peaks, but somewhere around 23 mils thick at its valleys.

You’d be forgiven for assuming that the more mils the liner is, the stronger the material is. While this is technically true, understand that the thickness we’re talking about here is thinner than a sheet of paper. The truth is that if a dog’s nail or a sharp rock hits the liner in the right spot, it’s going to rip regardless of it being a 20 mil or 30 mil liner. This is one of the biggest downsides of vinyl liners.

Quick Comparison: Pool Liner Thickness Options

Below is a side-by-side breakdown of 20 mil liner, 27 mil liner, 28 mil liner, and 30 mil liner options, including pros, cons, average lifespan, cost considerations, and the ideal type of pool owner for each.

Liner Thickness	Pros	Cons	Average Lifespan	Cost Impact	Best For
20 Mil Liner	Lower vinyl liner pools cost, easy installation, and highly flexible material.	Shorter lifespan, more vulnerable to punctures, and fades faster in direct sunlight.	7-10 years	The least expensive option, ideal if you want to minimize upfront expenses or plan for more frequent replacements.	Budget-conscious buyers and seasonal pool users.
27 Mil Liner	Slightly better resistance to abrasions; still flexible enough for easy installation.	Slightly more expensive; can be a bit harder to stretch.	7-10 years	A “middle ground” in pool liner thickness, offering slightly better resistance to abrasions without a big jump in price.	Balanced durability and affordability.
28 Mil Liner	Long lifespan and good performance in irregular pool shapes.	Costs more than 27 mil; installation is harder in cold weather.	7-10 years	In the upper-middle range for vinyl liner cost delivering strong value for long-term use.	Pools with heavy use and harsher conditions.
30 Mil Liner	Thickest standard liner for inground vinyl liner pools; best resistance to UV damage, abrasions; longest replacement cycle.	Highest material cost; requires experienced installers; less stretchable over complex shapes.	7-10 years	Being the premium option that can save money in the long run by delaying replacement.	Maximum durability and longest life.

 

20 Mil Liner

Best for: Budget-conscious buyers and seasonal pool users.

• Pros: Lower vinyl liner pools cost, easy installation, highly flexible material.
• Cons: Shorter lifespan, more vulnerable to punctures, fades faster in direct sunlight.
• Cost Impact: The least expensive option, ideal if you want to minimize upfront expenses or plan for more frequent replacements.

27 Mil Liner

Best for: Balanced durability and affordability.

• Pros: Slightly better resistance to abrasions; still flexible enough for easy installation.
• Cons: Slightly more expensive; can be a bit harder to stretch.
• Cost Impact: A “middle ground” in pool liner thickness, offering slightly better resistance to abrasions without a big jump in price.

28 Mil Liner

Best for: Pools with heavy use and harsher conditions.

• Pros: Long lifespan and good performance in irregular pool shapes.
• Cons: Costs more than 27 mil; installation is harder in cold weather.
• Cost Impact: Higher mid-range in vinyl pool liner cost, delivering strong value for long-term use.

30 Mil Liner

Best for: Maximum durability and longest life.

• Pros: Thickest standard liner for inground vinyl liner pools; best resistance to UV damage, abrasions; longest replacement cycle.
• Cons: Highest material cost; requires experienced installers; less stretchable over complex shapes.
• Cost Impact: Being the premium option that can save money in the long run by delaying replacement.

How Thickness Affects Vinyl Liner Cost

While pool liner thickness affects upfront price, it also impacts the long-term cost of owning a vinyl liner pool. A thinner 20 mil liner may cost less initially, but it may need to be replaced sooner than the thicker options, quickly raising your pool’s lifetime cost.

On the other hand, a 30 mil liner costs more upfront but can last much longer, reducing the frequency of replacement and overall lifetime expenses.

Choosing the Right Thickness

When deciding between a 20 mil liner, 27 mil liner, 28 mil liner, and 30 mil liner, consider:

1. Budget: How much you’re willing to spend now versus over the pool’s lifetime.
2. Usage: Although a tear can happen in any liner, if you’re planning on having dogs swim in the water, a thicker liner will offer marginally better protection from sharp nails.
3. Climate: Strong UV rays and extreme temperature swings can wear liners faster.
4. Shape & Features: Complex pool shapes may benefit from thinner, more flexible liners.
5. Long-Term Plans: If you’re building a pool in your forever home, a thicker liner could be a better investment.

Final Thoughts

Choosing the right thickness for your pool’s liner is about balancing cost, durability, and lifestyle.

• 20 mil liner – Lowest cost, and easiest to install.
• 27 mil liner – Good balance of price and performance.
• 28 mil liner – Strong durability without the full premium price.
• 30 mil liner – Longest lifespan and best protection for heavy-use pools.

Regardless of the thickness of your liner, its lifespan and functionality depend on the quality of the installation and maintenance from you, the homeowner. If you’re in the Northwest Indiana area are are thinking about purchasing an inground vinyl liner pool for next summer, reach out to Royal Pools G2 Landscaping for a consultation. For more educational pool content, check out the articles below or feel free to dive into our learning hub at the top of our page. Till next time!

Vinyl Liner Pool Rundown: Pros, Cons, And Manufacturing Process

Pool Liners: Will 30 Mil Liners Last Longer Than 20 Mil Liners?

Top 5 Vinyl Liner Manufacturers of 2025

Written by Logan Edgemon