{"id":4555,"date":"2026-09-29T13:08:21","date_gmt":"2026-09-29T13:08:21","guid":{"rendered":"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/"},"modified":"2026-09-29T13:08:21","modified_gmt":"2026-09-29T13:08:21","slug":"how-to-close-an-inground-pool","status":"publish","type":"post","link":"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/","title":{"rendered":"How to Close an Inground Pool: A Practical Fall Winterization Guide"},"content":{"rendered":"<h2>Water Chemistry Targets for Winter Closing<\/h2>\n\n<p>Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. Here are your targets:<\/p>\n<!-- PCC AI SUMMARY START -->\n<section class=\"pcc-answer-card\" data-ai-summary=\"true\">\n  <h2>Quick answer<\/h2>\n  <p>How to Close an Inground Pool: A Practical Fall Winterization Guide: Water Chemistry Targets for Winter Closing Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. Here are your targets: pH: 7.2-7.6 (aim for 7.4) Total Alkalinity: 80-120.<\/p>\n<\/section>\n<!-- PCC AI SUMMARY END -->\n<ul>\n<li><strong>pH:<\/strong> 7.2-7.6 (aim for 7.4)<\/li>\n<li><strong>Total Alkalinity:<\/strong> 80-120 ppm<\/li>\n<li><strong>Calcium Hardness:<\/strong> 200-400 ppm (vinyl: 175-225 ppm)<\/li>\n<li><strong>Free Chlorine:<\/strong> 1-3 ppm before adding shock<\/li>\n<li><strong>After shocking:<\/strong> 10-12 ppm (it&#8217;ll fade over winter)<\/li>\n<\/ul>\n\n<p>Why these numbers matter: Low pH and alkalinity create corrosive water that etches plaster and eats metal components. High calcium causes scaling. And inadequate sanitizer lets algae colonize before your cover even settles.<\/p>\n\n<p>Your pool&#8217;s volume determines exactly how much of each chemical you need. A 15,000-gallon pool requires roughly twice the chemicals of an 8,000-gallon pool. Use our <a href=\"https:\/\/poolchemicalcalculator.com\/volume\">pool volume calculator<\/a> to get your exact number, then dial in your chemistry with these tools:<\/p>\n\n<ul>\n<li><a href=\"https:\/\/poolchemicalcalculator.com\/chlorine\">Free chlorine calculator<\/a> \u2014 determine shock dose<\/li>\n<li><a href=\"https:\/\/poolchemicalcalculator.com\/ph\">pH calculator<\/a> \u2014 adjust pH safely<\/li>\n<li><a href=\"https:\/\/poolchemicalcalculator.com\/alkalinity\">Alkalinity calculator<\/a> \u2014 raise or lower TA<\/li>\n<li><a href=\"https:\/\/poolchemicalcalculator.com\/calcium-hardness\">Calcium hardness calculator<\/a> \u2014 prevent scaling or etching<\/li>\n<\/ul>\n\n<p>The <a href=\"https:\/\/poolchemicalcalculator.com\/app\">Pool Chemical Calculator app<\/a> runs all these calculations from your phone, poolside. Punch in your test results and volume, and it tells you exactly what to add.<\/p>\n\n\n<h2>Pool closing supplies<\/h2>\n\n<p>Disclosure: As an Amazon Associate, Pool Chemical Calculator may earn from qualifying purchases.<\/p>\n\n<figure class=\"pcc-amazon-cta-image\"><a href=\"https:\/\/www.amazon.com\/s?k=inground+pool+closing+kit+winter+plugs+pool+antifreeze+cover+pump&#038;tag=poolcalc04-20\" rel=\"sponsored nofollow noopener\" target=\"_blank\"><img decoding=\"async\" src=\"https:\/\/poolchemicalcalculator.com\/news\/wp-content\/uploads\/2026\/09\/how-to-close-an-inground-pool-amazon-cta-20260929.png\" alt=\"Shop Amazon Pools button with inground pool closing supplies including plugs, pool antifreeze, cover pump, air pillow, and cover hardware\" loading=\"lazy\" \/><\/a><figcaption>Pool closing supplies can help protect lines, plugs, covers, and equipment during winter. As an Amazon Associate, Pool Chemical Calculator may earn from qualifying purchases.<\/figcaption><\/figure>\n\n<hr>\n\n<h2>Step-by-Step Inground Pool Closing Instructions<\/h2>\n\n<h3>Step 1: Clean the Pool Thoroughly<\/h3>\n\n<p>Start with a spotless pool. Any debris left behind becomes food for bacteria and stains surfaces over months of sitting.<\/p>\n\n<p><strong>Tasks:<\/strong><\/p>\n<ul>\n<li>Skim the surface completely<\/li>\n<li>Brush walls, steps, and the waterline tile<\/li>\n<li>Vacuum the entire floor (don&#8217;t rely on the automatic cleaner)<\/li>\n<li>Empty all baskets \u2014 skimmer and pump<\/li>\n<li>Clean the waterline with tile cleaner to remove oils and scale<\/li>\n<\/ul>\n\n<p>Spend 45-60 minutes here. A clean pool closes better and opens easier.<\/p>\n\n<h3>Step 2: Test and Balance Water Chemistry<\/h3>\n\n<p>Test your water with fresh strips or a liquid kit. Don&#8217;t trust strips older than 6 months \u2014 they degrade.<\/p>\n\n<p><strong>Adjustment order matters:<\/strong><\/p>\n<ol>\n<li>Total alkalinity first (it affects pH readings)<\/li>\n<li>pH second<\/li>\n<li>Calcium hardness third<\/li>\n<li>Sanitizer last<\/li>\n<\/ol>\n\n<p>Make adjustments over 2-3 days if possible. Big chemical swings stress pool surfaces. If you&#8217;re closing this weekend, at least wait 4 hours between major additions and retest before the next one.<\/p>\n\n<h3>Step 3: Shock the Pool<\/h3>\n\n<p>Add granular shock to reach 10-12 ppm free chlorine. For a 20,000-gallon pool, that&#8217;s typically 2-3 pounds of calcium hypochlorite shock, depending on your starting chlorine level.<\/p>\n\n<p><strong>Important:<\/strong> Shock at dusk. Sunlight destroys unstabilized chlorine within hours. You want maximum sanitizer contact time before you close.<\/p>\n\n<p>Run the pump overnight after shocking to distribute chemicals evenly.<\/p>\n\n<h3>Step 4: Add Winter Closing Chemicals<\/h3>\n\n<p>The day after shocking (chlorine should be back to 3-5 ppm), add your winter chemical kit. A good <a href=\"https:\/\/www.amazon.com\/dp\/B004BGKNXA?tag=poolcalc04-20\">pool closing kit<\/a> includes:<\/p>\n\n<ul>\n<li>Winter algaecide (prevents growth under the cover)<\/li>\n<li>Stain and scale preventer (protects surfaces and equipment)<\/li>\n<li>Enzyme treatment (digests oils and organic buildup)<\/li>\n<\/ul>\n\n<p>Follow the kit&#8217;s dosing instructions based on your pool volume. Kits are typically sized for 15,000 or 20,000 gallons \u2014 if your pool is larger, buy two.<\/p>\n\n<h3>Step 5: Lower the Water Level<\/h3>\n\n<p>How far you lower the water depends on your cover type and climate:<\/p>\n\n<ul>\n<li><strong>Solid cover:<\/strong> 4-6 inches below the skimmer mouth<\/li>\n<li><strong>Mesh cover:<\/strong> 12-18 inches below the skimmer (accounts for rainwater accumulation)<\/li>\n<li><strong>Mild climate, solid cover:<\/strong> 4 inches below is fine<\/li>\n<li><strong>Heavy freeze climate:<\/strong> 6+ inches provides extra safety margin<\/li>\n<\/ul>\n\n<p>Use your filter&#8217;s &#8220;waste&#8221; setting to drain directly out (backwash hose to a drain area). Don&#8217;t drain through the filter \u2014 you&#8217;re about to winterize it.<\/p>\n\n<p><strong>Never drain an inground pool completely.<\/strong> Groundwater pressure can actually pop a vinyl liner or float a concrete shell. Always leave most of the water in place.<\/p>\n\n<h3>Step 6: Blow Out the Plumbing Lines<\/h3>\n\n<p>This is the critical step that prevents freeze damage. You need to force all water out of every line.<\/p>\n\n<p><strong>Equipment options:<\/strong><\/p>\n<ul>\n<li>Shop vac set to blow (works for simple setups)<\/li>\n<li>Cyclone blower (pool-specific, highly effective)<\/li>\n<li>Air compressor with regulator set to 25-30 PSI max<\/li>\n<\/ul>\n\n<p><strong>Process for each line:<\/strong><\/p>\n<ol>\n<li>Remove the pump drain plugs and filter drain plug<\/li>\n<li>Attach blower to skimmer line<\/li>\n<li>Blow air until you see strong bubbles at the main drain (30+ seconds of steady bubbles)<\/li>\n<li>Move to each return line \u2014 blow until air rushes from that jet for 30+ seconds<\/li>\n<li>Immediately plug each return\/skimmer as you finish<\/li>\n<\/ol>\n\n<p>Use <a href=\"https:\/\/www.amazon.com\/dp\/B00GAHOHYU?tag=poolcalc04-20\">winter expansion plugs<\/a> designed for freeze protection. They&#8217;re rubber with a wingnut that compresses the plug tight. The expansion design allows slight movement if any residual water freezes.<\/p>\n\n<h3>Step 7: Add Pool Antifreeze to Lines (When Needed)<\/h3>\n\n<p>Do you need <a href=\"https:\/\/www.amazon.com\/dp\/B00AU7MANI?tag=poolcalc04-20\">pool antifreeze<\/a> after blowing lines? Here&#8217;s the honest answer:<\/p>\n\n<p><strong>Yes, add antifreeze if:<\/strong><\/p>\n<ul>\n<li>You couldn&#8217;t blow lines thoroughly (weak blower, complex plumbing)<\/li>\n<li>Your area sees temperatures below 20\u00b0F regularly<\/li>\n<li>You have a main drain line that can&#8217;t be completely cleared<\/li>\n<li>Any line has low spots that trap water<\/li>\n<\/ul>\n\n<p><strong>You can skip antifreeze if:<\/strong><\/p>\n<ul>\n<li>You used a powerful blower and verified 30+ seconds of air from every opening<\/li>\n<li>Your climate rarely drops below 25\u00b0F<\/li>\n<li>All lines run with consistent slope toward the pool<\/li>\n<\/ul>\n\n<p>Pool antifreeze is non-toxic (propylene glycol) and safe for pools. Use 1 gallon per line in cold climates. Pour it into the skimmer and lines after blowing but before plugging.<\/p>\n\n<h3>Step 8: Drain and Store Equipment<\/h3>\n\n<p>Remove drain plugs from:<\/p>\n<ul>\n<li>Pump housing (usually two plugs \u2014 bottom and front)<\/li>\n<li>Filter tank (bottom drain)<\/li>\n<li>Heater (check manufacturer instructions \u2014 some have multiple drains)<\/li>\n<li>Chlorinator or salt cell<\/li>\n<li>Any booster pumps (cleaner pump, water feature pump)<\/li>\n<\/ul>\n\n<p>Store drain plugs in the pump basket so you find them in spring.<\/p>\n\n<p>If you have a cartridge filter, remove the cartridge, hose it clean, and store it indoors. Sand filters should be backwashed before closing and left with the valve in the &#8220;winterize&#8221; position (if available) or between settings.<\/p>\n\n<p><strong>Multiport valve:<\/strong> Leave the handle between settings so internal springs don&#8217;t stay compressed all winter.<\/p>\n\n<h3>Step 9: Install the Winter Cover<\/h3>\n\n<p><strong>Safety covers<\/strong> (mesh or solid with anchors) offer the best protection. They&#8217;re secure, keep debris out, and prevent accidents.<\/p>\n\n<p><strong>Solid floating covers<\/strong> require a <a href=\"https:\/\/www.amazon.com\/dp\/B0CFHJ1LLL?tag=poolcalc04-20\">cover pump<\/a> to remove rainwater and snowmelt. Without one, water weight will sink and damage the cover \u2014 or dump all that dirty water into your pool.<\/p>\n\n<p><strong>Cover installation tips:<\/strong><\/p>\n<ul>\n<li>Remove any sharp objects from the coping that could tear the cover<\/li>\n<li>For safety covers: use the included hardware; don&#8217;t skip anchors<\/li>\n<li>Tension should be snug but not drum-tight<\/li>\n<li>For solid covers: add the cover pump immediately; set it on a crate to keep it above the cover surface<\/li>\n<\/ul>\n\n<hr>\n\n<h2>When to Stop and Hire a Professional<\/h2>\n\n<p>DIY closing works great for straightforward setups: skimmer, 2-4 returns, simple suction-side cleaner, no heater or spa. But some configurations genuinely need professional attention.<\/p>\n\n<p><strong>Call a pro if you have:<\/strong><\/p>\n<ul>\n<li>Attached spa with separate jets and dedicated plumbing<\/li>\n<li>In-floor cleaning system (pop-up heads with buried manifolds)<\/li>\n<li>Multiple valves and you&#8217;re not 100% sure what each one controls<\/li>\n<li>Heat pump or gas heater and you&#8217;ve never drained it before<\/li>\n<li>Slide, waterfall, or water feature with hidden plumbing<\/li>\n<li>Any lingering doubt about whether you&#8217;ve cleared all lines<\/li>\n<\/ul>\n\n<p>A professional closing costs $200-400 depending on your region and pool complexity. Compare that to $600+ for a cracked return line repair or $1,500+ for a destroyed heater heat exchanger.<\/p>\n\n<hr>\n\n<h2>Troubleshooting Common Closing Problems<\/h2>\n\n<h3>Problem: Can&#8217;t get air to blow from a return<\/h3>\n\n<p><strong>Likely cause:<\/strong> Valve partially closed, debris blockage, or line routing you don&#8217;t know about.<\/p>\n\n<p><strong>Solution:<\/strong> Check all valves are fully open. Try blowing from the return side back toward the equipment. If still stuck, add extra antifreeze to that line or call a technician.<\/p>\n\n<h3>Problem: Water keeps refilling the skimmer after draining<\/h3>\n\n<p><strong>Likely cause:<\/strong> You&#8217;re draining below a suction line or the main drain is feeding water back.<\/p>\n\n<p><strong>Solution:<\/strong> Close the main drain valve if accessible. You may need to add antifreeze to the skimmer line and plug it quickly.<\/p>\n\n<h3>Problem: Cover pump runs constantly<\/h3>\n\n<p><strong>Likely cause:<\/strong> Low spot in cover pooling water, or pump can&#8217;t keep up with rain.<\/p>\n\n<p><strong>Solution:<\/strong> Add air pillows under the cover to create a center peak. Upgrade to a higher-capacity pump. Check pump intake isn&#8217;t clogged with debris.<\/p>\n\n<h3>Problem: Pool turned green under the cover during a warm spell<\/h3>\n\n<p><strong>This happens.<\/strong> A mesh cover allows sunlight through, and warm fall weeks promote algae growth.<\/p>\n\n<p><strong>Solution:<\/strong> If it&#8217;s still above freezing, remove the cover, shock heavily, run the pump until clear, and re-close with additional algaecide.<\/p>\n\n<hr>\n\n<!-- PCC RELATED LINKS START -->\n<section class=\"pcc-related-guides\">\n  <h2>Related pool calculators and guides<\/h2>\n  <ul>\n    <li><a href=\"https:\/\/poolchemicalcalculator.com\/volume\">Pool volume calculator<\/a><\/li> <li><a href=\"https:\/\/poolchemicalcalculator.com\/chlorine\">Free chlorine calculator<\/a><\/li> <li><a href=\"https:\/\/poolchemicalcalculator.com\/ph\">pH calculator<\/a><\/li> <li><a href=\"https:\/\/poolchemicalcalculator.com\/alkalinity\">Alkalinity calculator<\/a><\/li> <li><a href=\"https:\/\/poolchemicalcalculator.com\/forecast\">Pool chemical forecast<\/a><\/li> <li><a href=\"https:\/\/poolchemicalcalculator.com\/news\">Pool maintenance blog<\/a><\/li>\n  <\/ul>\n<\/section>\n<!-- PCC RELATED LINKS END -->\n<h2>Frequently Asked Questions<\/h2>\n\n<h3>What chemicals do I need to close an inground pool?<\/h3>\n\n<p>You need pH adjuster (up or down), alkalinity increaser if needed, calcium hardness increaser (for plaster\/concrete pools), granular chlorine shock, winter algaecide, and stain\/scale preventer. A complete closing kit contains the last three. Figure 2-3 pounds of shock for a typical 15,000-20,000 gallon pool.<\/p>\n\n<h3>How far below the skimmer should I lower an inground pool?<\/h3>\n\n<p>Lower water 4-6 inches below the skimmer mouth for solid covers. For mesh covers, go 12-18 inches below since rainwater will accumulate. In extremely cold climates, err toward the deeper drain for extra freeze protection.<\/p>\n\n<h3>Can I close an inground pool myself?<\/h3>\n\n<p>Yes, if your pool has a simple plumbing setup (skimmer, 2-4 returns, no heater, no attached spa). You need a way to blow out lines \u2014 a shop vac on reverse, a rented blower, or a compressor. If you have complex plumbing, a heater, in-floor cleaners, or an attached spa, hire a professional for your first closing, then decide if you can handle future years.<\/p>\n\n<h3>Do I need pool antifreeze after blowing out lines?<\/h3>\n\n<p>Not always. If you successfully blew strong air through every line for 30+ seconds, and your climate stays above 20\u00b0F, you can skip it. But antifreeze is cheap insurance \u2014 use 1 gallon per line in cold climates or any line you couldn&#8217;t fully clear.<\/p>\n\n<h3>When should I close my inground pool for winter?<\/h3>\n\n<p>Close when water temperature consistently stays below 65\u00b0F. Closing too early (water still warm) encourages algae growth under the cover. In most northern climates, that&#8217;s mid-October to early November.<\/p>\n\n<hr>\n\n<h2>Sources<\/h2>\n\n<ul>\n<li><a href=\"https:\/\/www.cdc.gov\/healthy-swimming\/toolkit\/pool-chemical-safety.html\">CDC Pool Chemical Safety Guidelines<\/a> \u2014 Safe handling practices for pool chemicals<\/li>\n<li><a href=\"https:\/\/www.cdc.gov\/healthy-swimming\/about\/home-pool-and-hot-tub-water-treatment-and-testing.html\">CDC Home Pool Water Treatment and Testing<\/a> \u2014 Water quality standards and testing guidance<\/li>\n<li><a href=\"https:\/\/www.lowes.com\/n\/how-to\/close-your-pool-for-winter\">Lowe&#8217;s Winterization Guide<\/a> \u2014 Step-by-step closing overview<\/li>\n<li><a href=\"https:\/\/www.thisoldhouse.com\/pools\/how-to-winterize-a-pool\">This Old House: How to Winterize a Pool<\/a> \u2014 Detailed winterization walkthrough<\/li>\n<\/ul>\n\n<hr>\n\n<h2>Get Your Chemistry Right Before Closing<\/h2>\n\n<p>Don&#8217;t guess on chemical doses. Wrong amounts waste money and leave your pool vulnerable. The <a href=\"https:\/\/poolchemicalcalculator.com\">Pool Chemical Calculator<\/a> gives you exact measurements based on your pool&#8217;s volume and current test results. Balance your water correctly this fall, and you&#8217;ll thank yourself when spring arrives.<\/p>\n\n<p><strong><a href=\"https:\/\/poolchemicalcalculator.com\/app\">Open the Pool Chemical Calculator \u2192<\/a><\/strong><\/p>\n\n<hr>\n\n<!-- PCC AFFILIATE PRODUCTS START -->\n<section class=\"pcc-affiliate-products\"><style>.pcc-affiliate-products{background:#f0f8ff;border:1px solid #d0e8f0;border-radius:12px;padding:20px;margin:30px 0}.pcc-affiliate-heading{display:flex;justify-content:space-between;gap:18px;align-items:end;margin-bottom:14px}.pcc-affiliate-heading h2{margin:0}.pcc-affiliate-heading p{max-width:360px;color:#557;font-size:.86rem;line-height:1.45;margin:0}.pcc-affiliate-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.pcc-affiliate-card{display:grid;grid-template-rows:auto 1fr;text-decoration:none;color:inherit;background:#fff;border:1px solid #d0e8f0;border-radius:10px;overflow:hidden;min-width:0}.pcc-affiliate-card img{width:100%;height:140px;object-fit:contain;background:#fff;padding:10px;border-bottom:1px solid #e2f0f6}.pcc-affiliate-card div{padding:12px}.pcc-affiliate-card span{display:block;color:#0576a8;font-weight:800;font-size:.78rem;margin-bottom:5px}.pcc-affiliate-card strong{display:block;color:#123;font-size:.94rem;line-height:1.25}.pcc-affiliate-card p{color:#456;font-size:.82rem;line-height:1.38;margin:8px 0}.pcc-affiliate-card em{color:#0576a8;font-style:normal;font-weight:800;font-size:.82rem}@media(max-width:780px){.pcc-affiliate-heading{display:block}.pcc-affiliate-heading p{max-width:none;margin-top:6px}.pcc-affiliate-grid{grid-template-columns:1fr}.pcc-affiliate-card{grid-template-columns:112px 1fr;grid-template-rows:auto}.pcc-affiliate-card img{height:100%;min-height:124px;border-bottom:0;border-right:1px solid #e2f0f6}}<\/style><div class=\"pcc-affiliate-heading\"><h2>Recommended pool supplies<\/h2><p>As an Amazon Associate, Pool Chemical Calculator earns from qualifying purchases.<\/p><\/div><div class=\"pcc-affiliate-grid\"><a class=\"pcc-affiliate-card\" href=\"https:\/\/www.amazon.com\/dp\/B007ZUD2IU?tag=poolcalc04-20&amp;linkCode=osi&amp;th=1&amp;psc=1\" target=\"_blank\" rel=\"sponsored nofollow noopener\"><img decoding=\"async\" src=\"https:\/\/m.media-amazon.com\/images\/I\/31ZLhziU+5L._SL160_.jpg\" alt=\"Calcium hardness increaser\" loading=\"lazy\"><div><span>Calcium hardness increaser<\/span><strong>SpaGuard Spa Calcium Hardness Increaser, 12 oz, Single Pack<\/strong><p>Raises calcium hardness to reduce corrosive water risk in plaster, concrete, and equipment.<\/p><em>View on Amazon<\/em><\/div><\/a><a class=\"pcc-affiliate-card\" href=\"https:\/\/www.amazon.com\/dp\/B002NSRD5C?tag=poolcalc04-20&amp;linkCode=osi&amp;th=1&amp;psc=1\" target=\"_blank\" rel=\"sponsored nofollow noopener\"><img decoding=\"async\" src=\"https:\/\/m.media-amazon.com\/images\/I\/51jS00uqkSL._SL160_.jpg\" alt=\"Pool test kit\" loading=\"lazy\"><div><span>Pool test kit<\/span><strong>Taylor K-1000 Basic Residential Pool &amp; Spa Test Kit<\/strong><p>Accurate readings make every chlorine, pH, alkalinity, calcium, and CYA dose safer.<\/p><em>View on Amazon<\/em><\/div><\/a><a class=\"pcc-affiliate-card\" href=\"https:\/\/www.amazon.com\/dp\/B006MHSKZ2?tag=poolcalc04-20&amp;linkCode=osi&amp;th=1&amp;psc=1\" target=\"_blank\" rel=\"sponsored nofollow noopener\"><img decoding=\"async\" src=\"https:\/\/m.media-amazon.com\/images\/I\/41+7BDSaM-L._SL160_.jpg\" alt=\"Alkalinity increaser\" loading=\"lazy\"><div><span>Alkalinity increaser<\/span><strong>SpaGuard Total Alkalinity Increaser, 2 lb, Single Pack<\/strong><p>Raises total alkalinity so pH is less likely to bounce around after treatment.<\/p><em>View on Amazon<\/em><\/div><\/a><\/div><\/section>\n<!-- PCC AFFILIATE PRODUCTS END -->\n\n<!-- PCC APP CTA START -->\n<section class=\"pcc-app-cta\" data-pcc-app-cta=\"true\">\n  <h2>Get exact pool chemical doses<\/h2>\n  <p>Pool Chemical Calculator turns your test readings, pool volume, and target levels into exact treatment amounts for chlorine, pH, alkalinity, calcium, stabilizer, salt, and more.<\/p>\n  <p><a href=\"https:\/\/poolchemicalcalculator.com\/app\"><strong>Open the Pool Chemical Calculator app<\/strong><\/a> for iOS, Android, or web.<\/p>\n<\/section>\n<!-- PCC APP CTA END -->\n<!-- PCC AI SEO STRUCTURED DATA START -->\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"BlogPosting\",\"@id\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/#article\",\"headline\":\"How to Close an Inground Pool: A Practical Fall Winterization Guide\",\"description\":\"Water Chemistry Targets for Winter Closing Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. Here are.\",\"url\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/\",\"mainEntityOfPage\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/\",\"image\":\"https:\/\/poolchemicalcalculator.com\/images\/cards\/Forecast-Card-01.png\",\"dateModified\":\"2026-09-29T13:08:16.860962+00:00\",\"author\":{\"@type\":\"Organization\",\"name\":\"Pool Chemical Calculator\"},\"publisher\":{\"@type\":\"Organization\",\"name\":\"Pool Chemical Calculator\",\"url\":\"https:\/\/poolchemicalcalculator.com\"}},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/poolchemicalcalculator.com\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Pool Care Blog\",\"item\":\"https:\/\/poolchemicalcalculator.com\/news\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"How to Close an Inground Pool: A Practical Fall Winterization Guide\",\"item\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/\"}]},{\"@type\":\"SoftwareApplication\",\"@id\":\"https:\/\/poolchemicalcalculator.com#app\",\"name\":\"Pool Chemical Calculator\",\"applicationCategory\":\"UtilitiesApplication\",\"operatingSystem\":\"iOS, Android, Web\",\"url\":\"https:\/\/poolchemicalcalculator.com\/app\",\"downloadUrl\":[\"https:\/\/itunes.apple.com\/us\/app\/pool-chem-calculator\/id1453351222\",\"https:\/\/play.google.com\/store\/apps\/details?id=com.poolchemicalcalculator.poolcalc\"],\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"USD\"}},{\"@type\":\"FAQPage\",\"@id\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/#faq\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What chemicals do I need to close an inground pool?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"You need pH adjuster (up or down), alkalinity increaser if needed, calcium hardness increaser (for plaster\/concrete pools), granular chlorine shock, winter algaecide, and stain\/scale preventer. A complete closing kit contains the last three. Figure 2-3 pounds of shock for a typical 15,000-20,000 gallon pool.\"}},{\"@type\":\"Question\",\"name\":\"How far below the skimmer should I lower an inground pool?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Lower water 4-6 inches below the skimmer mouth for solid covers. For mesh covers, go 12-18 inches below since rainwater will accumulate. In extremely cold climates, err toward the deeper drain for extra freeze protection.\"}},{\"@type\":\"Question\",\"name\":\"Can I close an inground pool myself?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes, if your pool has a simple plumbing setup (skimmer, 2-4 returns, no heater, no attached spa). You need a way to blow out lines \u2014 a shop vac on reverse, a rented blower, or a compressor. If you have complex plumbing, a heater, in-floor cleaners, or an attached spa, hire a professional for your first closing, then decide if you can handle future years.\"}},{\"@type\":\"Question\",\"name\":\"Do I need pool antifreeze after blowing out lines?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Not always. If you successfully blew strong air through every line for 30+ seconds, and your climate stays above 20\u00b0F, you can skip it. But antifreeze is cheap insurance \u2014 use 1 gallon per line in cold climates or any line you couldn't fully clear.\"}},{\"@type\":\"Question\",\"name\":\"When should I close my inground pool for winter?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Close when water temperature consistently stays below 65\u00b0F. Closing too early (water still warm) encourages algae growth under the cover. In most northern climates, that's mid-October to early November.\"}}]},{\"@type\":\"HowTo\",\"@id\":\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/#howto\",\"name\":\"How to Close an Inground Pool: A Practical Fall Winterization Guide\",\"description\":\"Water Chemistry Targets for Winter Closing Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. Here are.\",\"step\":[{\"@type\":\"HowToStep\",\"position\":1,\"name\":\"Clean the Pool Thoroughly\",\"text\":\"Start with a spotless pool. Any debris left behind becomes food for bacteria and stains surfaces over months of sitting.\"},{\"@type\":\"HowToStep\",\"position\":2,\"name\":\"Test and Balance Water Chemistry\",\"text\":\"Test your water with fresh strips or a liquid kit. Don't trust strips older than 6 months \u2014 they degrade.\"},{\"@type\":\"HowToStep\",\"position\":3,\"name\":\"Shock the Pool\",\"text\":\"Add granular shock to reach 10-12 ppm free chlorine. For a 20,000-gallon pool, that's typically 2-3 pounds of calcium hypochlorite shock, depending on your starting chlorine level.\"},{\"@type\":\"HowToStep\",\"position\":4,\"name\":\"Add Winter Closing Chemicals\",\"text\":\"The day after shocking (chlorine should be back to 3-5 ppm), add your winter chemical kit. A good pool closing kit includes:\"},{\"@type\":\"HowToStep\",\"position\":5,\"name\":\"Lower the Water Level\",\"text\":\"How far you lower the water depends on your cover type and climate:\"},{\"@type\":\"HowToStep\",\"position\":6,\"name\":\"Blow Out the Plumbing Lines\",\"text\":\"This is the critical step that prevents freeze damage. You need to force all water out of every line.\"},{\"@type\":\"HowToStep\",\"position\":7,\"name\":\"Add Pool Antifreeze to Lines (When Needed)\",\"text\":\"Do you need pool antifreeze after blowing lines? Here's the honest answer:\"},{\"@type\":\"HowToStep\",\"position\":8,\"name\":\"Drain and Store Equipment\",\"text\":\"Remove drain plugs from:\"}]}]}<\/script>\n<!-- PCC AI SEO STRUCTURED DATA END -->\n","protected":false},"excerpt":{"rendered":"<p>Water Chemistry Targets for Winter Closing Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. Here are.<\/p>\n","protected":false},"author":4,"featured_media":4553,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"googlesitekit_rrm_CAowle7eCw:productID":"","footnotes":""},"categories":[1],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to Close an Inground Pool: A Practical Fall Winterization Guide - Pool Chemical Calculator<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/poolchemicalcalculator.com\/news\/how-to-close-an-inground-pool\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to Close an Inground Pool: A Practical Fall Winterization Guide - Pool Chemical Calculator\" \/>\n<meta property=\"og:description\" content=\"Water Chemistry Targets for Winter Closing Get your water balanced before you close \u2014 this protects your pool surfaces and equipment all winter. 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