I live near you, Michigan to be precise. We can swim for about 5 months unless you have a heated pool. I just bought a house and looked at many along the way. The houses with pools were far nicer than the ones without and my wife and I attributed that to the pool. We thought they had to come down in price to sell the house. Take a look in your area and see for yourselves.
I see this was a little too late, but I wanted to put my 2 cents in.

thats ok all posts are welcome. you are right homes in Michigan at least in my area (Livingston County) tend to be a little bit higher priced when they have a pool. They cost alot to put in and alot of people just cannot afford them. I am a realtor and most of the homes I deal with are over $400,000 and most of them have pools unless they are on a lake already. Welcome to the forum by the way, I am the moderator for the real estate area if you have questions please email me at reedmurray@michigansfineliving.com

I'm a Realtor in Southern California and pools defintely add value here. Appraisers add $20,000. For some reason, most buyers want a pool. This did not seem to be the case years ago- it used to be about 50/50. However, because you live in the Northeast, I would think the sitution would differ.

1. It is cold much of the time??? So can you use the pool much?

2. You might be one of the few houses with a pool; therefore, buyers might like that you house offers something that others don't???

I'm not an expert on your part of the country. That's my best advice.

If you have an expensive home where where, say 25%, of similar priced homes in you area have pools it will not detract from value. It may not, however, add to value equal to cost.