You should check with your local parks and recreation department. Many have facilities with pools that they lease to other groups,like swim teams and triathlon clubs. They will tell you what they require for such use.
And yes, you need to make sure that your insurance covers your using a pool. Most cover all that you do that is not outside your scope of practice. But the worst time to find out what isn’t covered is when it has already happened.
There is a chance that you could use a private pool, such as at an apartment or condo complex. But often these location are not willing due to increasing their potential liabiity.