Winter Water Level for a Fiberglass Pool Under a Safety Cover: What Latham Says
Latham’s published guidance for its fiberglass pools is to keep the water 4 to 6 inches below the skimmer under a solid cover, and about 12 to 18 inches below the skimmer under a mesh cover. It also says never to drain the pool fully. Other fiberglass pool makers publish different numbers, so follow the winter instructions for your own pool model.
By the Calm Water Pools Team | Last verified: September 28, 2026
What Latham says
Latham’s article “Are Fiberglass Pools A Good Choice For Cold Climates?” (May 5, 2026) gives two figures, depending on the cover:
- Solid cover: the water “should remain 4-6 inches below the skimmer” to keep the skimmer from freezing when temperatures drop.
- Mesh cover: the water “should remain around 12-18 inches below the skimmer,” which protects the skimmer from freezing and leaves room for melted ice and snow that drains through the mesh.
- Draining: “Never fully drain your pool, as it can create costly structural damage.”
- Monitoring: a solid cover hides the water, so Latham advises adding a level check to your weekly routine.
The two numbers differ because the covers behave differently. A mesh cover lets rain and snowmelt into the pool, so the water needs headroom. A solid cover keeps that water on top, where it is pumped off or drained, so the pool level stays put.
What other makers say
Winter water level is not settled across the industry, and the published guidance differs:
| Source | What it says | Applies to |
|---|---|---|
| Latham, cold-climate article (May 2026) | 4 to 6 inches below the skimmer with a solid cover; 12 to 18 inches below the skimmer with a mesh cover | Latham fiberglass pools, by cover type |
| Latham, winter cover care tips | Keep the water “within 12″ of the top of the pool wall” | Safety covers in general |
| Thursday Pools | Just below the midway point of the skimmer; “never dip below the skimmer level in a fiberglass pool” | Thursday fiberglass pools, no cover distinction |
| Leisure Pools | About an inch below the skimmer | Leisure fiberglass pools, no cover distinction |
These are not in agreement, and we are not going to pick a winner. Each maker is writing for its own shells, plumbing and cover setups. That is why your pool’s owner’s manual outranks any general article, including this one.
What to do
- Find the winter instructions for your pool model. Check your owner’s manual, or ask the installer who built your pool.
- Match the level to your cover type. If your manufacturer gives separate solid and mesh figures, as Latham does, use the one for your cover.
- Never drain the shell. Latham’s warning is consistent with our own guide to fiberglass pools in winter, which explains how draining exposes a shell to groundwater pressure.
- Check the level on a schedule. Weekly under a solid cover, per Latham, and at least whenever a big storm or thaw passes.
- Ask before lowering if your yard stays wet. If you have had groundwater problems, ask your installer before lowering the water level.
Calm Water Pools sells the cover; we cannot set the right level for your particular pool. For choosing a cover type, see our mesh vs. solid guide. For timing, see when to order a winter safety cover.
Frequently asked questions
What water level should I keep under a solid cover on a fiberglass pool?
Latham’s published guidance is 4 to 6 inches below the skimmer with a solid cover. Other makers give different figures, so follow the winter instructions for your pool model.
What water level should I keep under a mesh cover?
Latham’s published guidance is around 12 to 18 inches below the skimmer with a mesh cover, which leaves room for meltwater that drains through the mesh. Confirm the figure for your pool with your manufacturer.
Can I drain my fiberglass pool for winter?
No. Latham says to never fully drain the pool because it can cause costly structural damage. Lowering the level is not the same as draining it, and the right level depends on your pool.
Why do solid and mesh covers need different levels?
Mesh lets rain and snowmelt drain into the pool, so the level needs headroom. A solid cover holds that water on top, where it is pumped off, so the pool level stays closer to normal.
Who should I ask if I am not sure?
Your pool’s owner’s manual first, then the installer who built your pool or the pool’s manufacturer. Calm Water Pools sells covers and cannot set the level for a specific pool.
Sources: Latham, Are Fiberglass Pools A Good Choice For Cold Climates? (May 5, 2026); Latham, winter pool cover care tips; Thursday Pools, winter pool safety covers; Leisure Pools, closing your fiberglass pool. Manufacturer guidance changes; your pool’s manual governs.