my guess is the dc pools will be closed. any private gyms or clubs with drop-in fees?
Sport and Health has pools in Bethesda and Tenley (Wisc Ave) and guest fees are $20-25/day. Bethesda has a smaller pool (4 tight lanes) but free parking. Tenley has 5 slightly wider lanes and validated parking is $2. In my experience, Beth is a bit more crowded than Tenley. Happy Swimming.