Puberty
That time in a parent's life where they start to notice that their water bill starts to increase as their big load of joy of a teenager starts aging.

They refuse to believe that's the reason why but it's true, puberty can get expensive.

(if you're still unsure of why this is happening,it's because your son/daughter masturbates frequently in the shower)
Mother: God donut rick! Our water bill is twice as much as it was last month! Is this a mistake?!

Father: Hunny... it's puberty.