Guide to Winterizing Your Fiberglass Pool

You can feel the temperature start to drop before the forecast confirms it, and that first cool snap means pool season is winding down. If you’re unprepared, freezing weather can damage a fiberglass pool. A few precautions now can prevent an expensive repair later.

Dickson Family Pools & More has experience installing fiberglass pools in Taylors and works with pool owners year-round, including during seasonal pool closings. In this guide, we’ll walk through winterizing your fiberglass pool so your investment stays protected until next summer.

Why Cold Weather Puts Your Pool at Risk

Once the pool water remains below about 65 degrees, it is time to begin winterizing your fiberglass pool. Complete the process before the first hard freeze to prevent standing water from freezing inside pumps, filters, and plumbing lines. This circulation system is key to how swimming pools work, and protecting it keeps everything ready to run once the weather warms up.

Balance the Water Chemistry First

Test your water a week before closing to allow adjustments. Aim for a pH between 7.2 and 7.4 and alkalinity between 80 and 120 parts per million. Fiberglass surfaces, unlike concrete, do not need added calcium, which can cause staining if levels run high.

Lower the Water to the Right Level

Unlike some other pool types, fiberglass pools should never be drained completely. Part of properly winterizing a fiberglass pool is following the pool and cover manufacturers’ instructions for the correct winter water level, since some systems require the normal operating level. Others allow you to lower the water slightly below the skimmer.

Keeping enough water in the pool helps the shell resist pressure from the surrounding ground. Lowering the water beyond the manufacturer’s specified level can leave the shell vulnerable to groundwater pressure, which may cause the walls to bow or separate from the deck. A skimmer plug can protect the skimmer without additional draining, while a cover pump removes rainwater from a solid cover.

Protect the Plumbing Lines and Equipment

Freeze protection becomes the priority once you balance the water chemistry and set the water level. Before the first hard freeze, drain any pool plumbing lines or equipment still holding water, since a cracked fitting is costly to fix.

Addressing a few key areas helps mitigate most of this risk:

Pump and filter: Drain water from the pump basket and filter housing so nothing freezes inside.
Skimmer and returns: Blow out or plug the lines running to the skimmer and return jets.
Heater and chlorinator: Drain these separately, since manufacturers often list their own steps for each.

A pool professional can blow out the plumbing lines with compressed air if you’d rather not handle this step.

Add a Winterizing Chemical Kit

Once the water is balanced and the level is set, add a winterizing chemical kit made for fiberglass pools, including an algaecide and a stain and scale preventer to keep the water clear all winter. Skip products containing calcium hypochlorite, since they suit concrete and vinyl pools rather than fiberglass pools.

Choose and Secure a Winter Cover

A properly fitted winter pool cover keeps debris and sunlight off the water while your pool sits idle. Solid covers block light completely, which helps prevent algae growth, while mesh covers catch debris but let some water through.

A secure cover should meet the requirements for its specific design:

Proper fit: Install the cover according to its manufacturer’s tension requirements. Anchored safety covers should remain properly tensioned, while water-bag covers generally need enough slack to rest on the pool water.
Correct hardware: Attach safety-cover straps to their deck anchors or place water bags around the perimeter, depending on the cover system.
Regular checks: Remove debris periodically and use a cover pump to clear standing water from a solid cover. Check mesh-cover straps and anchors throughout the winter.

A cover in good condition makes spring opening faster with less debris in the water.

Keep Your Fiberglass Pool Ready With Dickson Family Pools & More

A well-prepared fiberglass pool is less vulnerable to cold-weather damage. A shell built to last decades needs only a short, predictable list of tasks to get through the off-season safely. Once you complete these steps each fall, closing your pool becomes routine maintenance, not a guessing game.

We work with pool owners across the Taylors area, whether they have a vinyl liner or fiberglass shell, helping with everything from seasonal shutdowns to decisions about fiberglass versus concrete pools. Ricky and our team focus on practical advice and dependable service.

If you’d rather leave your fiberglass pool’s winterization to a professional, call Dickson Family Pools & More in Taylors, SC, at (864) 581-7665.

author avatar
Ricky Owner
Ricky Dickson is the owner of Dickson Family Pools & More, serving homeowners throughout the Upstate of South Carolina. After years in the pool industry and hands-on experience in pool installation, maintenance, repairs, and customer service, Ricky founded Dickson Family Pools & More in Greenwood, SC, in 2025, committed to honest, dependable service and quality workmanship. As the company quickly grew, Ricky expanded by opening a second location in Taylors, SC, in 2026, allowing his team to better serve customers across the Upstate. His practical industry knowledge and dedication to customer satisfaction help homeowners make informed decisions about pool care, equipment, and outdoor living. Ricky enjoys sharing expert insights through educational articles covering pool maintenance, equipment, repairs, water care, and seasonal tips to help families protect their investment and enjoy their pools year-round.
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