Winterizing in-ground pool without blowing out lines


New member
Jul 7, 2020
Washington Il
Hello all!! First time, brand new pool owner. Had a great season this summer and with it being our first season I wanted to have the install company close the pool for the winter for us. It is an expense I would like to not incur going forward, but I wanted to have it done right and observe this first year in hopes that I can do it next year. So in preparation for the closing I scoured the interTubes for any and all information regarding closing an in-ground pool. All of them basically were the same:
  • Drain filter
  • Blow out lines
  • Cap and seal lines
  • Add some antifreeze for some insurance against a leak
  • Put Gizmo in skimmer
  • Cover
So going into it I kind of knew what to expect to happen when they came to close the pool. But here is what they actually did. They drained the filter and then poured antifreeze down the lines until they could see it coming out of the supplies in the pool. Then they capped the lines put in the gizmo and were done. They used close to 50 gallons of antifreeze. I went out and asked them if they were going to blow out the lines and they said that they don't need to with this method. Is this legit? This is from the company I bought the pool from so I would think they would know what they are doing. Just concerned because I always thought this was like an involved 3 - 4 hour process. They were here and gone in 40 minutes.

Thanks in advance for any and all help!

  • 15,000 gallon fiberglass pool
  • Salt Cell
  • In-ground
  • Freezing winters
  • Sand filter


Gold Supporter
Silver Supporter
Jul 8, 2013
Columbus, Ohio
This should be fun. I've always blown the lines like my pool installer showed me how to do. The engineer in me says lines full of anti-freeze don't freeze. Of course if it was that Dang easy why doesn't everyone do it this way? You did spend a lot of $ on anti-freeze.
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Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Depending on the antifreeze they used and if you vacuum out the antifreeze or flush it into the pool water the antifreeze can consume a lot of chlorine at opening if flushed into the pool.

They should have used non-toxic Pool Antifreeze or RV Antifreeze. Automotive antifreeze is toxic. Ethylene Glycol should never be used in winterizing a skimmer or pool.
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Gold Supporter
TFP Guide
Jun 16, 2019
No harm at all except for the $3-$5 a gallon. Maybe they get theirs in bulk for $1, but that’s still $50 when air is free after the initial purchase of a cyclone/compressor.
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Matt F 3

Well-known member
Feb 1, 2020
Plainfield Il
The question of the day is do they guarantee the pool?

I have 18 yards of concrete around the pool and if something breaks the PB is fixing the lines and replacing the concrete; For free. Money well spent IMO as I don't have to worry about it freezing.

My PB blew out the lines then capped them, put a bladder in the skimmer, then added a few gallons of pool antifreeze to the lines. They also drained the pump, filter and heater.
I'll watch them open it in the spring, they said its pretty easy. They don't mind showing clients how to open it the spring but strongly suggest they close it.



Well-known member
Jun 19, 2020
The engineer in me says lines full of anti-freeze don't freeze.
It absolutely does freeze. The difference is it doesn't expand anywhere near as much as water does. That's what prevents the bursting.

The antifreeze has a protection rating. (Protects down to X temperature.) Of course that rating is only achieved if it's 100% pure antifreeze. Used as described in this thread, it has invariably mixed with water, reducing the freeze protection.
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