Arlington, VA, Washington DC Metro Area
If you're looking for somewhere to pass a hot summer day, we have you covered with Ocean Dunes Waterpark, only 20 minutes outside of downtown DC. Part of Arlington County's Upton Hill Regional Park, Ocean Dunes features a 230-foot open slide, a 170-foot covered waterslide, and a play area with slides, water jets, and a 500-gallon dumping bucket. There's a large main pool for swimming and a smaller wading pool with little water jets for children under the age of 6. You can stay for lunch and eat at the small snack bar (outside food and beverages - other than water - are not permitted, although we have eaten a snack brought from home and no one said anything).
There is a daily rate or you can buy an Annual Pass that allows you to visit all five of Arlington's water parks. Upton Hill Regional Park also features a batting cage and a mini golf course, adjacent to the water park, if you want to make a day of it. You can pay $12 for a day per person for unlimited use of all the activity centers. During the summer, Ocean Dunes has theme days, like Family Fun Night Thursdays, when discounts may be available. There are lifeguards on duty and you can borrow lifejackets if you need them.