Water bill is very high and no visible leaks

[Heather De lap]

So very long story shortened my water bill is extremely high this month. We average $35.00 a month and this month it was $151.20. The jerk landlord told us in a very nasty little note to check out water leaks which we did and don't have. He claims we went through 19,500 gallons of water in April which means we used 650 gallons a day for 30 days. Not possible. We checked for leaks in the house and under it. We found nothing. We have an issue with a leaky toilet but it's been that way for 2 years and the bill is never higher than $35.00. Any ideas if this is an underground leak that has nothing to do with me or is my landlord price gouging me?