William H. Rumsey pool is next to Eastern Market at 7th and North Carolina SE. It’s a very no-frills pool, but I tend to be able to get good lane space as long as I don’t go when there are classes happening (e.g., evenings during the week are generally out). You just have to show your DC driver’s license to get in, or if you don’t have one yet you can show a copy of your lease or a utility bill.
Welcome to the neighborhood! Definitely feel free to say hi if you spot me at Rumsey in the mornings, I wear a pink or purple swim cap and have a DC tri water bottle –Liz