Possible Clues:

• What's left is wet, it seems, but one has it under control
• Sister ran (anag.)
• What keeps one back is that what's left is wet
• What's left is wet so one keeps it back
• How one stops what's left from getting wet
• What's left is wet if one holds it back
• Take a break before it's wet and holds one up
• 'If one holds this in check, what is left is wet (9)'
• Keeps back
• It keeps one back when what's left is wet