The T or C Municipal pool (at the corner of Charles and Daniels in TorC's hot springs district) usually opens on Memorial Day each year, and stays open through August for swim team practice, lap swims, water aerobics, and adult and open swims.
More info is on the City of Truth or Consequences' Municipal Pool page.
Some hotels - the Elephant Butte Inn, the Hot Springs Inn, and others we may not know about - have pools, and management may allow non-lodgers to swim for a fee, subject to policy.
Our hotels page contains a list of all hotels in Sierra County.
And there are always the lakes! Swimmers flock to our lakes every summer to have fun and cool off, and during less busy times, triathletes train for the Elephant Man and Dam It Man Triathlons.
Please stop in at any of the State Parks Visitor Centers for safety tips if you're planning on swimming at Elephant Butte or Caballo State Park!