This page covers state law only. Cities with their own rules have their own pages.
Delaware lawIn force
Delaware security deposit limits, escrow and return (with surety bond alternative)
How big can the deposit be?
Max 1 month's rent for a lease of a year or more.
Month-to-month: 1 month once you've rented a year. It comes back within 20 days after the lease ends, minus listed damages.
Who it covers
Exemptions: Limits do not apply to furnished rental units; federally-assisted housing regulations excepted for month-to-month tenancies. Pet deposits are separately capped at 1 month's rent.
The law, word for word
“No landlord may require a security deposit in excess of 1 month’s rent where the rental agreement is for 1 year or more …”