Thornton's Rec Center on Colorado and 112th can be found here:
https://www.cityofthornton.net/recre...on-center.aspx


Broomfield Rec Center is here:
http://www.ci.broomfield.co.us/Facil...nity-Center-41

The Broomfield pool used to host local HS swim meets and would probably be less crowded than the Thornton Rec Center pool.