Pool closing · Washington
When to Close Your Pool in Federal Way, WA: Deadline, Window & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Circle September 29 on the Federal Way calendar. Closing earlier traps warm, algae-friendly water under the cover; closing later gambles the plumbing against the first freeze, which the 1991–2020 normals place near November 14. The window opens September 19 — the live widget below shows how this year is actually tracking against it.
Federal Way closing dates at a glance
| Closing window | September 19 – September 29 |
|---|---|
| Close by (deadline) | September 29 |
| First freeze, 50% probability | November 14 |
| Open by (recommended) | May 24 |
| Opening window | May 17 – June 7 |
| 61°F crossing (7-day mean) | June 7 |
| Swim-season length (80°F+ days) | 0 days |
| NOAA normals station | Tacoma #1 · 5.6 mi · 25 ft |
A short season cuts both ways: every week opened before June 7 is a real slice of Federal Way's roughly 0-day warm-swim budget.
Put dates aside and follow the water: the Federal Way curve says roughly 51°F by mid-April, 61°F by mid-June, 68°F in mid-August, then back down through 56°F in mid-October. The summer ceiling sits near 68°F, and every window above is just a line drawn on this curve.
The 12-step Federal Way winterizing checklist
A closing is a plumbing project with a chemistry warm-up. Start a few days ahead of your target date, keep every dose per its product label, and don't skip the photographs — spring-you reassembles from them.
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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.
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Deep-clean the pool
Make the last cleaning the best one of the year: full skim, full brush, careful vacuum. Debris left behind steeps all winter and greets you as April's water problem.
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Service the filter one last time
One final filter service per the manual — cartridges rinsed and stored dry indoors, sand or DE backwashed. Winter turns trapped gunk into concrete.
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Apply winter chemicals per label
Run the winter kit through moving water: dose each product per its label with the pump on, give it a few hours to distribute, then start the shutdown. Chemistry added to still water stays where it lands.
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Lower the water level
Check the cover manufacturer's spec before touching the hose: solid covers typically want water below the skimmer mouth, mesh often barely lower than normal. Full draining is off the table entirely.
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Blow out the lines and plug returns
The blowout is the whole ballgame: drive air through each line until it runs dry, seat the plug against the airflow, move to the next. A dry line cannot burst, full stop.
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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.
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Add pool antifreeze where blowouts fall short
Any line you can't prove is dry gets pool-grade antifreeze at the label's rate per foot. Automotive antifreeze is toxic in this context — pool-rated only, always.
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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.
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Set the air pillow and cover
Float a centered air pillow, then land the cover and secure it the way its design intends — bags, cable, or straps. Ice sheets need somewhere to collapse inward, and the pillow is that somewhere.
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Calendar the off-season checks
Set a monthly reminder from September 29 to spring: check cover tension, pump off standing water, and glance at the water level. Fifteen minutes a month protects the whole closing job.
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Note this year's dates
Jot down when Federal Way's water actually cooled and when you closed. A two-line note beats memory next September 19 — your own yard runs a few days off any model, including ours.
What to buy before the rush
Every item below sells out somewhere in Washington every September. 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.
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Air pillow
Centers under the cover so ice pushes inward, not outward.
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Winter cover
The one purchase every other closing step depends on.
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Cover pump
Standing water is a cover killer; this is the counter.
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Expansion plugs + skimmer guard
Seals blown-out lines and sacrifices itself to skimmer ice.
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Pool antifreeze
For lines you can't verify dry — pool-grade only, per label.
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Winter closing kit
The under-the-cover chemistry, measured for your gallons.
How Federal Way compares locally
Statewide context: across the 21 Washington cities we model, Federal Way's September 29 deadline sits in the earlier half. Nearby, Auburn (6 mi) closes around October 1 and Tacoma (7 mi) around September 29 — treat gaps under a week as microclimate noise, not strategy. Spring planning restarts at the opening guide; the Federal Way pool season page keeps the whole year in one view.
Every number on this page traces to one instrument cluster: Tacoma #1, 5.6 miles southwest of Federal Way's center at an elevation near 25 feet. NOAA computed its 1991–2020 normals from roughly three decades of daily readings — long enough that one strange spring in King County barely moves the dates.
Field notes for Federal Way owners
The fifteen-minute monthly walk-around
Once a month all winter: pump or siphon standing water off solid covers, re-tension straps or top up water bags, confirm the level hasn't dropped enough to strand the cover, and glance at the pad for critter nests. Every major cover failure starts as a skipped walk-around.
The mesh-cover spring surprise, prevented in fall
Mesh-covered pools green up early because late-winter sun plus nutrient-carrying meltwater reaches the water. The fall counter-moves: close late and cold, dose the winter kit exactly per label, and plan an early-spring peek under the cover rather than a Memorial Day reveal.
Leaf season vs closing day
If your yard drops serious leaves, the cheap trick is a leaf net over the main cover through the drop, then one bulk removal before snow. Leaves that winter on (or worse, under) the cover steep like tea and hand you stained water and clogged pumps in spring.
Hard-winter homework
Where winter is long — Federal Way banks only about 0 warm-swim days — the closing carries months of load. Bury the effort where it counts: verified-dry lines, fully drained equipment, a skimmer guard, and a cover secured for real wind. A short season forgives a late opening; it never forgives a cracked pump.
Federal Way pool closing FAQ
What temperature should water be to close a pool?
The practical target is water in the low 60s°F or below at closing day. Our Federal Way model has the sustained cool-down starting September 19; closing between then and September 29 means chemistry stays put and the spring reveal is a mild one.
Can you close a pool too early?
You can, and warm-water closings are why "we opened to a swamp" stories exist. The fix is patience: let Federal Way's water cool through the mid-60s°F — around September 19 by our model — then close inside the window that ends September 29.
Do I need antifreeze in pool lines?
Blown-out, plugged lines don't need it; doubtful lines do. Use only antifreeze labeled for pools, at the label's rate per foot of pipe — never automotive antifreeze. In Federal Way the freeze clock starts around November 14, so settle this during closing, not during the first cold snap.
How far should I drain my pool for winter?
As far as your cover manufacturer specifies and no farther — typically a few inches below the skimmer mouth for solid covers, near normal level for many mesh systems with skimmer plugs. Never drain fully: an empty shell can shift or crack under groundwater pressure.
What happens if you don't winterize a pool?
Two failure modes. Where freezes reach the plumbing, expansion cracks pumps, filters, and fittings from the inside. Where they don't, an unwatched pool simply drifts green and unbalanced by spring. Federal Way has no published freeze normal to pin the date, so the winterizing above plus forecast-watching covers both risks.
When is the last safe date to close in Federal Way?
Treat September 29 as the deadline in Federal Way. It's derived from the 1991–2020 normals: the cool-down plus ten days (the freeze normal, November 14, leaves room to spare). Weather varies year to year, so watch the 10-day forecast in late September — an early cold snap moves the real deadline, and the widget above flags exactly that.
Email me when Federal Way hits the closing window
Data: NOAA 1991–2020 climate normals via Tacoma #1 (5.6 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.