How do you guys normally close your inground pool before winter?

J

James Carter

Member
So, I’m doing this for the first time and honestly kind of confused. Every guide I read seems to say something different. Some people say to drain the water below the skimmer, others don’t bother and just use one of those plugs. I’m also unsure about what chemicals I should be putting in before covering it. Do you treat it and then wait a few days, or cover it the same day? Would love to hear from people who’ve done it a few times. Anything you’d do differently if you were closing your pool again?
 
Great question. I usually lower the water below the skimmer just to be safe, but honestly, the skimmer plugs work fine too if your winters aren’t too harsh. For chemicals, I shock the pool and add algaecide, then let it circulate for a day or two before covering. That way the water's treated properly before it sits for months. Definitely clean the filter before closing, that’s one thing I used to skip.
 
I used to drain below the skimmer, but now I just blow out the lines and plug them. Way easier and less water waste. For chemicals, I treat it the same day and cover it once the pump has circulated for a few hours. I learned the hard way not to skip algaecide or the water turns green by spring. Also double-check your cover for gaps where leaves can sneak in.
 
I cover mine the same day I add chemicals, but I let the pump run for a few hours first. I drop in some shock and algaecide, balance the pH, and call it good. I’ve done both draining and plugging both work, but plugging is easier if your area doesn’t freeze too hard. Big thing is to clean the pool well first, so you’re not trapping junk under the cover all winter.
 
I used to be all over the place with this too! What works best for me is to cover the pool the same day and let the water circulate for a bit before sealing it off. I always add my chemicals first, but I’ve learned that giving it a quick scrub around the edges before covering it up keeps debris from sticking to the sides. Little things like that have saved me a lot of headache later when reopening the pool!
 
The first time I closed mine, I overthought everything and ended up rushing it right before a cold snap, wouldn’t recommend. Now I try to keep it simple but spread the steps over a couple of days so I’m not scrambling. I usually check the forecast and pick a calm, dry weekend to close up.

I balance the water and add the closing chems one day, then vacuum and backwash the next morning before dealing with the cover. I don’t drop the water level unless we’ve had a ton of rain and it’s already close to overflowing. I use a skimmer plug and haven’t had issues with freezing, but I’m in a mild climate. One thing I do differently now is toss a tennis ball or two in the water before covering, sounds silly, but it helps pick up oils and sunscreen residue that stick around even after cleaning.

If I had to do it over again, I’d have invested in a better cover from the start. The cheap one I used the first year let in a bunch of junk and made spring cleanup miserable. Just something to think about if you’re still shopping around.
 
I feel like my pool-opening ritual is less about the chemicals and more about pretending to be an expert while secretly Googling everything. 😅 But hey, if the pool water is still green by the end of the day, I just tell myself it’s a “natural spa experience.” Anyone else trying to make pool care look like a full-on science project?
 
  • Lower water just below the skimmer mouth.
  • Blow out & plug return lines to prevent freeze damage.
  • Add winterizing chemicals (shock, algaecide, stain preventer) per label.
  • Run pump 1–2 hours to mix.
  • Cover the pool securely.
 
My first season I over-complicated closing: drained below the skimmer, added every chemical in sight, then rushed to slap the cover on. Water still got foggy under there! Now I just skim, add a light shock, run the pump four hours, then cover. Way less drama and zero surprise algae in spring!
 
Great suggestions from everyone! I’ve been trying to perfect my winterizing process, and one thing I’ve done differently is using a pool cover pump. It’s saved me a ton of time by keeping the cover from collecting water. Has anyone else used this, or do you just let nature take its course?
 
First winter I did the whole routine… then spent an hour in spring guessing which plug went where 😅. Now my last step is ‘photos + labels,’ and I toss a leaf-net over the cover. Reopening is way calmer. Anyone else use a leaf-net topper?
 
I have a 30' inground pool, sand filter and multiple speed pump.
I keep hearing "blow out the system"...
I know the lines need to be cleared of any water or blowing out, where do I connect and is this something I would use my air compressor for?
Do I plug the jets and skimmer before, what do I leave open for water discharge?
 
I was in the same boat my first year, all those “blow out the lines” instructions sounded way more complicated than they actually are. You can definitely use a regular air compressor; just hook it up to the pump drain plug or skimmer line, and blow air through until you see bubbles coming out of the returns. Then plug the jets while the air’s still pushing through so no water sneaks back in.

For the skimmer, I use a gizmo plug instead of draining below it, that way I don’t have to lower the water level much. Once everything’s sealed up, I disconnect the pump and filter, drain them completely, and leave the valves half open so nothing gets trapped. It sounds like a lot, but once you’ve done it once, the whole process takes maybe an hour next time around.
 
The biggest thing I learned after a couple seasons is that there isn’t one “correct” checklist, it’s more about protecting the parts that can crack and not trapping problems under the cover.

My routine now is pretty simple. I pick a stretch of dry weather, give the pool a really thorough clean (walls, steps, waterline), and make sure the chemistry is calm, not aggressive. I don’t like closing right after a heavy shock because I’ve found it can be rough on liners and fittings when it sits sealed for months. I’ll let it circulate overnight so everything evens out.

For water level, I aim for moderate, not extreme. Just enough room so ice or meltwater isn’t pressing directly into the skimmer, but not so low that the cover is unsupported. Then I focus most of my effort on the plumbing, making sure lines are empty, sealed, and the equipment is fully drained. That’s where real winter damage usually comes from, not the exact inch the water sits at.

One thing I do differently now than my first year is slowing down. I spread it over two days instead of rushing it all at once. When I tried to do everything in one afternoon, I always missed something small. Since I started taking my time, spring openings have been way less dramatic.
 
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