Wading Pools/Splash Pads!

Lakewood  has six parks with wading pools.  Good thing LB'ers can join in.
Open 11am-4pm for kids 3-7 years old
Open everyday: Mayfair, Palms
Open Monday, Wednesday, Friday, Saturday, & Sunday: Del Valle & San Martin
Open Tuesday, Thursday, Saturday, & Sunday: Bloomfield, Boyar
Wednesdays: Boyar, Del Valle, Mayfair, San Martin will be open 5pm-7:30pm

Weekends: all pools open 11am-4pm
http://www.lakewoodcity.org/services/recreation/aquatics.asp

In Cerritos, Liberty Park has a great little splash pad for the toddler set.
You can also cool off at the water play areas at Long Beach Towne Center and the Cerritos Library.

Splash Pad at Sigler Park in Westminster is free and open every day from Noon-5pm starting June 22 to September 7.  7200 Plaza St., Westminister.

And apparently the water was turned back on at Dotson Park in Stanton.  Free.
10350 Fern Avenue, Stanton

Atlantis Park in Garden Grove. $2 admission.  13630 Atlantis Way, Garden Grove, CA 92844

A little bit further is the Lemon Park Spray Pool. 701 S. Lemon, Fullerton 

For the older kids, CSULB has open swim hours during the summer: 11am-6pm; $2/person

Buccaneer Bay in La Mirada opens June 21.  The family-fun “Buccaneer Bay” combines the excitement of a water park with pirate themed features throughout. Buccaneer Bay features a flowing river channel, three water slides, a children’s interactive play structure, zero-depth beach entry and two spray pad areas. Pirate themed elements include: a marooned ship, a dramatic skull rock, shade canopies that resemble sails, cannon walls, wharf plank benches, and crow’s nests.  Open daily in summer 10:30am-5:30pm.  $17.95/person, under 48" $12.95.  Family Friday Nights 4pm-8pm. $14.95/person, under 48" $10.95. 
13806 La Mirada Blvd.
La Mirada, CA 90638
Phone: (562) 902-3191