Gumball's total water intake on Monday, Thursday, and Saturday is 9 x 3 = <<9*3=27>>27 liters.
And his total water intake on Tuesday, Friday, and Sunday is 8 x 3 = <<8*3=24>>24 liters.
So his total water intake for 6 days is 24 + 27 = <<24+27=51>>51 liters.
Therefore Gumball's water intake on Wednesday is 60 - 51 = <<60-51=9>>9 liters.
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