The only time I get squirrels into my bird feeders is when the squirrel feeders run out. There are many beautiful bird feeders on the market and squirrels will chew. The best advice is to just get some cheap ones. That way you are not driving yourself nuts trying to control what you can not. Squirrels are a wonderful addition to any habitat and their antics will both amuse and soothe you.
Life is to short to get mantic about squirrels in bird feeders.
The most important thing in providing water is to be sure to keep it clean and change out the water daily. You do not have to spend a lot of money to have a water source. The saucers for potted plants with a few rocks work very well. There are small patio fountains to buy or make from a kit. If you have the space you may want to have a pond.