Next door to Knott's Berry Farm is its affiliated water park, boasting a 750,000-gallon wave pool, dozens of high-speed slides, tubes and flumes (including 10 new slides for 2017), and one of the world's longest lazy river attractions. You must have a bathing suit without rivets or metal pieces to go on some slides. Bring a beach towel and a change of dry clothes.
The park is open from Memorial Day (end May) to Labor Day (start of September), plus additional May and September weekends. Look online for often significant discounts off the full admission. Rental lockers ($10 to $22 per day) and private cabanas (from $99) are available.