Last year our dog park committee convinced a local city to let us host a Pooch Pool Party to help raise funds for our dog park. They agreed and it was a BLAST. Over the course of 4 hours nearly 200 dogs came and went. My dogs were there from about 10am to 5pm and could barely walk by the end of the day.
Yes the water was a little green...city didn't really read our email about keeping the chlorine going ..
Trying to consider being brave
If you have nice pools in your area...talk to the parks & recs dept or whoever is in charge of the pool. The parties happen after the pools are closed to humans and before the pool is drained and clean.
Sadly citizens of the city we held ours in...well...not knowing the above they complained and the city, not knowing good responses, caved and no more pool parties for us. *Sigh* If they'd only been smart about it they could have fielded the concerns quite effectively and even made money in later years. Ah well.