Just sold one today.  The clause that we use up here is:

The Seller represents and warrants that the swimming pool and equipment are now, and on the completion date shall be, in good working order. The Parties agree that this representation and warranty shall survive and not merge on completion of this transaction but apply only to the state of the property existing at completion of this transaction.
The Seller agrees to winterize the swimming pool and equipment prior to completion , and shall provide a written undertaking on completion that the Seller shall be responsible for any costs or expenses incurred by the Buyer if the swimming pool and equipment are not properly winterized, provided only that the Buyer gives written notice of any claim to the Seller not later than 6:00 pm on the 1st day of June, 2016, failing which the Seller accepts no responsibility for costs.

We don't winterize in AZ - but what Susan Emo said is the way we would handle it...

Good morning Renee. I like the answer that Susan Emo shared, it makes good sense.

I would put a clause in the contract that covers the pool being in working condition during the summer, similar to what Susan Emo said.

I feel that Susan Emo nailed it.  I am of no help because we do not winterize in my area. 

We use something similar to Susan Emo's answer. I think hers is better than ours

Susan's response is the same that I would use.  We are in the same province.

As Debbie Laity said, outdoor, in ground pools are a rarity in Colorado. I would take what Susan gave you to an attorney as a starting place.

Susan Emo just laid it out for you.... nicely done....

I think we have two properties with in ground pools in my entire county. They just aren't the popular thing in my market. 

Like Susan's clause. Some escrow money might be better because you know it is there!

Either a clause similar to what Susan Emo noted, but I might advise my principals to hold aside in an escrow fund several thousand dollars, just in case. After all, what were the sellers thinking? They knew the home was listed for sale.

I use a similar form like Susan's where the seller signs. It is a leap of faith though because selers wont warranty that winter ice wont make mess. Often seeing receiopts for who closed and winterized it helps. 

This is tricky ! But as a Listing Agent I tell the Sellers to have it PROFESSIONALLY closed this time around and to have that company write a report stating it's condition at closure.

Hmmm good one, we don't have that issue down here.

 Good morning Renée. Put in a clause that will have the sellers warrant the operation of the swimming pool when it is reopened in the spring.

We don't winterize pools here. Just make sure they are well maintained.

Renee Paray - that's a tricky one.

Have seller agree to fix all the issues related to swimming pool  and put some big chunk of money in escrow.

You can get all the assurances you want but if it is opened six months later how can you say that the problem is pre-existing and of course, how do you prove it in court?

I have an amount set aside with the closing company to cover the cost of potential repairs

I ask the buyer if they are comfortable taking a chance that a problem can arise when the pool is opened back up in the spring. I have never had a buyer insist to have it dewinterized and filled to test it out in cold freezing weather. They always have moved forward with the sale with no known problems coming up later that I was aware of.

Yes, agree with all answers. 

Great anwer, Susan!

Renee - No winterizing of pools here in Arizona, but I could see that as a real issue if not handled properly in the purchase contract. I think Susan Emo has the right idea.

Not an issue here in Dallas, as pools are not winterized.  But having the equipment and systems that are visible gone over by a pool technician would be advisable.  Plus a home warranty could be lifesaver once the weather warms back up.

It appears that you have received an answer. We have few pools in our area.

I don't have this issue in FL, but I assume that you could escrow some funds until the spring when the pool can be inspected.

We don't winterize our pools in California so not an issue here.

I see some great responses here.

Outdoor pools are very rare in Albuquerque. I haven't run into this problem. 

You could set aside funds in escrow until an inspection or simply have an iron-clad agreement spelling out this issue or talk with the pool service guy or do a dry run or if there is honesty in the air, go with that...that's all I could come up with

I would ask for maintenance records, and ask to talk the the company that has done work on te pool. I would also check into getting a warrany specific for the pool. yet, still wite something similar to what Susan Emo wrote.

I don't know that in Charlotte I've sold more than a handful of houses with pools (we are not a big private pool community). And as it turned out, I've never sold one that was winterzied. But if I did, I suppose I'd want some language in the contract that the seller warranties condition of pool until it can be dewinterized and tested. But I would have an attorney write this.

We have an addendum at our office that has the details. 

We have an addendum that allows for pools to be tested after it warms up - after settlement.  

I would ask for maintenance receipts.