Pool closing · Oregon
When to Close Your Pool in Beaverton, OR: Deadline, Window & Checklist
Last updated: July 15, 2026 · Model window year: 2026 · dates · checklist · FAQ
Circle October 5 on the Beaverton 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 6. The window opens September 25 — the live widget below shows how this year is actually tracking against it.
Beaverton closing dates at a glance
| Closing window | September 25 – October 5 |
|---|---|
| Close by (deadline) | October 5 |
| First freeze, 50% probability | November 6 |
| Open by (recommended) | May 23 |
| Opening window | May 16 – June 6 |
| 61°F crossing (7-day mean) | June 6 |
| Swim-season length (80°F+ days) | 59 days |
| NOAA normals station | Beaverton 2 SSW · 1.6 mi · 270 ft |
A short season cuts both ways: every week opened before June 6 is a real slice of Beaverton's roughly 59-day warm-swim budget.
Four water checkpoints anchor Beaverton's year in the model: mid-April at about 51°F, mid-June at 62°F, mid-August near the 68°F peak zone, and mid-October easing through 56°F. The dates in the table are where those numbers cross the thresholds that matter.
The 12-step Beaverton 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
Do the chemistry midweek, close on the weekend: alkalinity and pH into label ranges with days of circulation left to spread them. Winter locks in whatever state the water holds on closing day.
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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
Send the filter into winter clean: backwash the sand or DE, rinse and dry the cartridges indoors. Media stored dirty over winter hardens into a spring problem no backwash fixes.
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Apply winter chemicals per label
Dose the winter kit while the pump still runs — every product exactly per its label for your volume — so the chemistry is fully mixed before the system goes quiet.
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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.
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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
If any line can't be verified dry, add pool-grade antifreeze per its label. Use only pool antifreeze — automotive products don't belong in pool plumbing.
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Drain the equipment
Open every drain plug on the pump, filter, heater, and chlorinator, and store the plugs in the pump basket so spring reassembly is a one-stop hunt. Move what you can indoors.
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Set the air pillow and cover
Pillow first, cover second, tension last. A properly centered pillow turns the winter ice sheet from a wall-pressing ram into a harmless dome.
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Store chemicals properly
Seal opened containers, keep oxidizers and acids separated, and store everything cool, dry, and locked away from kids and pets — exactly as each label describes.
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Calendar the off-season checks
Set a monthly reminder from October 5 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 Oregon 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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Expansion plugs + skimmer guard
Seals blown-out lines and sacrifices itself to skimmer ice.
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Pool antifreeze
Backup for unverifiable lines; label rate per foot of pipe.
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Winter closing kit
The under-the-cover chemistry, measured for your gallons.
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Air pillow
A soft target for the ice sheet, centered under the cover.
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Winter cover
Measure with overlap; the winter workhorse over everything else.
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Cover pump
Keeps rain and melt off a solid cover all season.
How Beaverton compares locally
Statewide context: across the 8 Oregon cities we model, Beaverton's October 5 deadline sits in the earlier half. Nearby, Hillsboro (7 mi) closes around September 30 and Portland (9 mi) around October 10 — treat gaps under a week as microclimate noise, not strategy. Spring planning restarts at the opening guide; the Beaverton pool season page keeps the whole year in one view.
The measuring stick here is Beaverton 2 SSW — 1.6 miles to the south, elevation about 270 feet. Its 1991–2020 record is what the model reads for Beaverton; your backyard in Washington County will run a touch warmer or cooler with shade, wind, and pavement, which is exactly the slack the two-week lead absorbs.
Field notes for Beaverton owners
Match the drainage plan to the cover
Solid covers shed nothing — they need a cover pump staged before the first storm and checked after each one. Mesh covers drain themselves but pass silt that settles all winter. Either way, the plan is decided in October, not improvised in January when the cover is an ice sheet.
What comes indoors
Cartridges, the cover pump when idle, chemical containers, and anything with a small motor overwinter better in the garage. Cold cycling is hard on plastics and seals; shelf space is cheaper than replacements. Label a single bin now and spring assembly becomes a scavenger hunt with a map.
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.
Hard-winter homework
Where winter is long — Beaverton banks only about 59 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.
Beaverton 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 Beaverton model has the sustained cool-down starting September 25; closing between then and October 5 means chemistry stays put and the spring reveal is a mild one.
Can you close a pool too early?
Early closing is the mistake the whole model is built to prevent from the other direction. A cover installed over 70°F water is a terrarium: sanitizer decays, algae compound, nobody looks for months. Beaverton's water isn't reliably out of that zone until about September 25 — the calendar's first cold weekend doesn't change that.
Do I need antifreeze in pool lines?
Only for lines you can't verify dry — a proper blowout makes antifreeze unnecessary. Where doubt remains, use pool-grade product at its label rate, never automotive. No freeze-probability normal is published near Beaverton, so let the live forecast, not a calendar, tell you when freeze protection starts mattering.
How far should I drain my pool for winter?
Only to the line your cover manufacturer prints — a few inches below the skimmer for most solid covers, close to operating level for many mesh designs with the skimmer plugged. The water you leave in is structural: it holds the shell against groundwater all winter.
What happens if you don't winterize a pool?
Expect equipment damage first — cracked pump volutes, split filter tanks, ruptured heater exchangers — then plumbing leaks that surface at startup. In Beaverton, normals put the first freeze near November 6; everything after that date is borrowed time for an unwinterized system.
When is the last safe date to close in Beaverton?
Our model's practical deadline is October 5 — set by the cool-down plus ten days (the freeze normal, November 6, leaves room to spare). Push much past it and you're winterizing in freeze-warning weather, rushing the blowout, and hoping the cover goes on before the first hard night. Inside the September 25–October 5 window, none of that drama applies.
Email me when Beaverton hits the closing window
Data: NOAA 1991–2020 climate normals via Beaverton 2 SSW (1.6 mi); live outlook by Open-Meteo. Full attribution on the sources page. Model assumptions and error bars on methodology.