Family Fun in the Sun! Only in Moses Lake will you find Washington State's premier outdoor aquatic center. This family-oriented facility offers many activities and is designed for swimmers of all ages and abilities. Located in Central Washington, the weather is warm and the sun shines almost every day. Surf 'n Slide Water Park is ideal for vacationers, serious and recreational swimmers, and especially families. Admission fees are very reasonable. Surf 'n Slide Water Park is located close to area hotels, downtown shopping and the sparkling waters of Moses Lake.