The City of O’Fallon charges a security deposit of $150 to water and sewer customers, and $50 to customers who only have trash service. This security deposit is held until the customer has paid 12 timely and consecutive bills, or until the customer moves out of the home. At this time, the security deposit is applied as a credit to your account and any remaining credit is sent to you as a refund check.  This helps ensure that any final balances for services are paid.