What Causes Wrinkles in My Pool Liner?

Wrinkles are caused by water imbalance or shifting ground underneath the liner. Ensure proper installation and maintain balanced water chemistry.

Why Pool Liner Wrinkles Are a Bigger Problem Than You Think

At first glance, a few wrinkles in your pool liner might seem like just a cosmetic issue. But if left unaddressed, they can lead to bigger problems. Wrinkles collect dirt, hide small tears, and cause uneven pressure points. Over time, this can shorten the lifespan of the liner and even damage the pool’s structure.

Wrinkles also make cleaning harder and swimming less enjoyable. Nobody wants to step on bunched-up vinyl or worry about their vacuum snagging mid-clean. So the sooner you identify the cause, the better.

What Causes Wrinkles in a Pool Liner?

There’s no single reason. Wrinkles can show up for several reasons, and understanding these helps you avoid repeat issues. Here are the most common causes:

1. Water Chemistry Imbalance

Poor water chemistry is one of the leading causes of liner wrinkles. Specifically:

• Low pH can cause the liner to absorb water and swell

• High chlorine levels can weaken vinyl

• Unbalanced alkalinity makes it harder to maintain consistent pH

When the liner absorbs water unevenly, it stretches and shifts, creating permanent folds.

2. Improper Installation

If your liner was not installed correctly, wrinkles can appear from the start. Common installation mistakes include:

• Not smoothing the liner evenly before filling

• Installing in cold weather (vinyl is less flexible)

• Using a liner that doesn’t fit the pool shape or dimensions well

Once water is added, it's hard to adjust the liner without draining the pool.

3. Groundwater and Drainage Issues

Water pressure under or around your pool can push the liner out of place. This is especially common with in-ground pools in areas with a high water table.

Signs of groundwater problems include:

• Wrinkles that appear after heavy rain

• Bulging spots on the pool floor or walls

• A “floating liner” feel underfoot

Proper drainage and sump systems can help manage this pressure.

4. Old or Stretched Liners

Vinyl liners have a limited lifespan. As they age, they lose elasticity and start to shrink or stretch unevenly. This leads to:

• Baggy areas around the base

• Loose sections near corners

• Wrinkles that won’t flatten, even after adjusting water levels

If your liner is over 8–10 years old, wrinkles may be a sign that it’s nearing the end.

5. Temperature Swings

Liners expand and contract with temperature. Rapid swings, especially during spring or fall; can cause wrinkles to form or existing ones to worsen. Pools that are covered and uncovered often during shoulder seasons may experience this more.

6. Draining and Refilling the Pool

Whenever a pool is drained completely, the liner shifts. If it’s not reset properly when refilled, wrinkles are almost guaranteed.

Tips to avoid this:

• Only drain when absolutely necessary

• Have a professional reset the liner during refills

• Refill the pool quickly to keep the liner from drying out

How to Prevent Pool Liner Wrinkles

Prevention starts with care. A wrinkle-free liner not only looks better, but it also lasts longer. Use these strategies to help keep your liner smooth:

1. Maintain balanced water chemistry
Keep your pH, alkalinity, and sanitizer levels in range year-round. Test at least weekly, or more often during heavy use.

2. Avoid complete draining
If you must lower the water level, never let it drop too low unless you’re working with a pro. Vinyl can shrink quickly when exposed to air.

3. Install in warm weather
If you’re getting a new liner, aim for installation when temperatures are between 70–85°F. The vinyl will be more flexible and easier to stretch into place.

4. Improve yard drainage
Add gutters, drainage lines, or a sump pump near the pool to manage heavy rain or high water tables.

5. Use a pool cover properly
Covers prevent temperature fluctuations and keep out excess rainwater, both of which reduce wrinkle risks.

How to Fix Wrinkles in a Pool Liner

Some wrinkles can be fixed, others may require a liner replacement. Here's how to tell the difference:

Minor Wrinkles (Can Be Repaired)

Try these steps:

• Warm up the liner: Use warm water or let the sun do the job

• Push out the wrinkle: Use a plunger or soft broom to smooth from the center outward

• Adjust water level: Lower a few inches and try resetting the liner gently

If wrinkles persist but the liner is in good shape, call in a pool technician. Professionals can use vacuums or specialized tools to smooth larger areas.

Major Wrinkles (May Require Replacement)

If you see the following, a new liner might be necessary:

• Deep creases that have hardened over time

• Discoloration or cracking along the folds

• Wrinkles that worsen after every adjustment

In some cases, reinstallation may be possible, but liners lose stretch over time. For liners past 10 years old, replacement is usually more cost-effective.

Is It Safe to Swim With Wrinkles in the Pool?

Technically yes, but it’s not ideal. Wrinkles can:

• Create tripping or slipping hazards

• Catch toes and cause minor injuries

• Trap dirt and algae, leading to cloudy water

If you notice new wrinkles forming, it’s best to address them before regular swimming continues. Long-term use with a wrinkled liner puts extra wear on both the liner and the pool structure.

Stay Ahead of Liner Problems

Pool liner wrinkles are frustrating, but they’re not mysterious. With the right care and attention, you can avoid most of the common causes. Keep your water balanced, protect your liner from temperature shocks, and deal with drainage around the pool. Catching wrinkles early keeps your pool looking clean and feeling great all season long