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.