My husband had lower back surgery 3 years ago and we saved up to put in a new pool since he uses it for low impact exercise because running hurts due to the impact can this be a medical write off?
Generally no. Only the part of the cost that is increased specifically due to medical needs is a medical expense. Such as if you installed a transfer device to help a person with limited mobility get in and out of the pool.
The rest of the cost is added to the cost basis of your home and may reduce your capital gain when you sell, but is not a medical or any other kind of deduction now.