When to Close Your Pool in Slidell, LA: Deadline, Window & Checklist

Slidell closing dates at a glance

Slidell's 164-day warm season leaves comfortable margins on both ends — the windows above aim you at the cheap-chemistry versions of each transition.

The same model in water terms: Slidell's estimated pool temperature runs about 66°F in mid-April, 80°F in mid-June, 82°F in mid-August, and 72°F in mid-October, peaking near 82°F. Those four checkpoints — not any calendar holiday — are what the windows above are protecting.

The 12-step Slidell winterizing checklist

The order matters more than the date: balanced water first, verified-dry lines before anything else freezes-proofs, and the cover only after everything below it is done. Work the list inside the window above.

1. Balance the water a few days ahead

   Start midweek for a weekend close: bring alkalinity and pH into their label ranges and let the water settle. What you seal under the cover is what the pool soaks in until spring.

2. Deep-clean the pool

   Skim, brush walls and steps, and vacuum carefully. Any leaves or algae you seal under the cover become spring's chemistry problem, so closing day cleanliness pays twice.

3. Service the filter one last time

   Backwash sand or DE, or pull and rinse cartridges, per the manual. A filter stored dirty cakes over winter and starts spring half-clogged.

4. Apply winter chemicals per label

   Add a winterizing kit or your usual closing chemicals exactly as their labels direct for your volume, with the pump still circulating so everything distributes before shutdown.

5. Lower the water level

   Drop the level as your cover manufacturer specifies — typically below the skimmer mouth for solid covers. Never drain a pool fully; groundwater pressure can damage the shell.

6. Blow out the lines and plug returns

   Air through every line — skimmer, returns, cleaner — until each blows dry mist, plugging returns while the air still pushes. Nothing else on this list protects as much plumbing per minute.

7. Protect the skimmer

   Install a skimmer guard bottle (or a plug rated for your skimmer) so ice that forms there crushes the sacrificial piece instead of cracking the skimmer body.

8. Add pool antifreeze where blowouts fall short

   Doubt is the criterion: any run you can't confirm dry gets pool-grade antifreeze at the label's per-foot rate. The automotive jug from the garage is for cars — it has no business in pool plumbing.

9. Drain the equipment

   Nothing on the pad should hold water overnight: pull the drain plugs from pump, filter, heater, and feeder, stash them all in the pump basket, and carry the portable pieces indoors.

10. Set the air pillow and cover

    Center an inflated air pillow, then fit the cover and secure it with water bags, cable, or straps as designed. The pillow gives ice a place to push besides your walls.

11. Remove and store ladders and rails

    Pull ladders, rails, and the diving-board hardware; rinse, dry, and store them out of the weather. Anchor sockets get a dab of protectant so spring bolts turn freely.

12. Calendar the off-season checks

    Set a monthly reminder from November 19 to spring: check cover tension, pump off standing water, and glance at the water level. Fifteen minutes a month protects the whole closing job.

What to buy before the rush

Every item below sells out somewhere in Louisiana every November. Stocking the short list before the rush costs nothing extra and saves the mid-project store run — the chemicals guide explains what each category actually does.

• Winter closing kit

  Closing chemistry in one box, dosed by pool volume.

• Air pillow

  Gives ice somewhere to push besides your pool walls.

• Winter cover

  Sized to overlap; the cheapest insurance the pool wears all winter.

• Cover pump

  Standing water is a cover killer; this is the counter.

• Expansion plugs + skimmer guard

  The blowout's finishing move — one per return, one for the skimmer.

• Pool antifreeze

  Backup for unverifiable lines; label rate per foot of pipe.

How Slidell compares locally

Two nearby data points to triangulate with: New Orleans, 18 miles from Slidell, models its close at December 2 (roughly two weeks later); Mandeville, 19 miles out, at November 11. Slidell's own window ends November 19. For the other half of the calendar see when to open in Slidell, or scan the full year on the season page.

Every number on this page traces to one instrument cluster: Slidell, 1.8 miles southeast of Slidell's center at an elevation near 10 feet. NOAA computed its 1991–2020 normals from roughly three decades of daily readings — long enough that one strange spring in St. Tammany County barely moves the dates.

Field notes for Slidell owners

Blowout first, antifreeze second

Air is the only guaranteed freeze protection: a line that's verifiably dry cannot burst. Antifreeze (pool-grade, per label) is the fallback for lines you can't confirm — long runs, low spots, water-feature plumbing. Doing antifreeze instead of a blowout, rather than in addition, is how most cracked returns happen.

Salt cells overwinter indoors

Remove the cell at closing, inspect and clean per the manufacturer, and store it inside with the unions capped. A dummy cell or spacer keeps the plumbing sealed. Cells left in outdoor plumbing through freezes are a common — and completely avoidable — spring casualty.

Gas heaters get the manual, not a guess

Every heater brand sequences its winterizing differently — drain plugs, blower considerations, gas supply, control settings. The generic advice (drain fully, close the valve) is right but incomplete; ten minutes with your model's manual protects the most expensive component you'll winterize.