If there is a pool that introduces a whole other set of problems with insurance, upkeep (from professionals) etc. It would be about 2000$ to $3000 a year for just cottage insurance, but with a pool it might be an extra $50-$100 a month? Having a housekeeper is one thing, but unless you were very familiar with pools and hot tubs, and have someone able to take care of it regularly, then there will be an additional cost to have someone specifically taking care of the hot tub and the pool, making sure all of the chemicals are OK. I believe that if you are a short term rental landlord you should supply safe drinking water (like a water cooler etc). No matter what, though if you ever do go to a cottage, it is in everyone’s best interest to pack extra water just in case anyway. I would definitely say that the showers will likely have some sort of filtration system built in, but you never know. With extreme heat this area does develop a lot of algae bloom, and you might get some thing like swimmers itch if the temperatures are too high and there are ducks or geese, but that is the same for a lot of places in Ontario. Depending on the walkout situation from the cottage to the water, might be the reason that there was a push to get a pool, because if it’s rocks, they could be slippery people can be injured, etc.