What is the maximum landlords may charge for security deposits?

Most states have imposed limits on how much landlords of residential leases may charge for security deposits, often capping deposits at an amount equal to one or two months' rent. Below is a recently updated table of security deposit maximums for all 50 states.

State-by-State Deposit Limits
Alabama One month's rent (excluding pet deposit, changes to premises, or liability increases) (Alabama Code 35-9A-201(a)) 
Alaska Two months' rent (except where rent exceeds $2,000/month) (Alaska Statutes 34.03.070(a))
Arizona One and a half months' rent (Arizona Revised Statute 33-1321(a))
Arkansas Two months' rent. This limitation does not apply if the landlord owns five or less dwellings UNLESS property management, including rent collection, is performed by third persons for a fee (A.C.A. § 18-16-303 & 304).
California Two months' rent for unfurnished dwellings; three months' rent for furnished dwellings (Civil Code Section 1950.5(b) & (c))
Colorado No limit under state law (note that cities and counties may impose their own limits on security deposits)
Connecticut Two months' rent for tenants under 62 years of age; one month's rent for tenants aged 62 or older (Conn. Gen Statu. 47a-21(b))
Delaware One month's rent for unfurnished leases lasting one or more years; one month's rent (with the exception of federally-assisted housing regulations) for primary residential tenancies of undefined terms or month to month where the tenancy has lasted one year or more. After the expiration of one year, the landlord shall immediately return, as a credit to the tenant, any security deposit amount in excess of one month's rent (25 Delaware Code 5514(a)(1) to (4)). Delaware also caps pet deposits at one month's rent regardless of the duration of the lease (25 Delaware Code 5514(i)(2)). No pet deposit may be required for certified service/training support animals for disabled tenants (25 Delaware Code 5514(i)(3)).
District of Columbia One month's rent (DC Municipal Regulations Ch 14. S. 308.2)
Florida No limit under state law (note that cities and counties may impose their own limits on security deposits)
Georgia No limit under state law (note that cities and counties may impose their own limits on security deposits)
Hawaii One month's rent (excluding pet deposit which may also be less than or equal to one month's rent) (HRS S.521-44)
Idaho No limit under state law (note that cities and counties may impose their own limits on security deposits)
Illinois No limit under state law (note that cities and counties may impose their own limits on security deposits)
Indiana No limit under state law (note that cities and counties may impose their own limits on security deposits)
Iowa Two months' rent (Iowa Code 562A.12(1)). The deposit must be held in a federally insured bank account with no commingling, OR the deposit may be placed into a trust account, which may be interest bearing. If interest bearing, interest earned during the first five years of the tenancy goes to the landlord, and interest earned thereafter to the tenant (Iowa Code 562A.12(2)).
Kansas One month's rent for unfurnished dwellings; one and a half month's rent for furnished dwellings; and up to an additional half month's rent may be charged for a pet deposit. (Kan Stat Ann 58-2550(a))
Kentucky No limit under state law (note that cities and counties may impose their own limits on security deposits)
Louisiana No limit under state law (note that cities and counties may impose their own limits on security deposits)
Maine Two months' rent. This limitation does not apply in buildings with no more than five units with one of which being occupied by the landlord (14 MRSA 6032 & 6037(2)).
Maryland Two months' rent (Md Code Ann 8-203(b))
Massachusetts Deposit is capped at an amount equal to the first month's rent (Mass. Gen. Laws Ann. Cha. 186, Section 15B(1)(b)(iii)). The landlord must give the tenant a receipt for the security deposit (including the amount, name of receiver, name of lessor if different, date received, and description of premises, with signature) (Mass. Gen. Laws Ann. Ch 186, Section 15B(2)(b)). The landlord must maintain a record of the security deposit amount, date, period, and deductions/withholding details for tenant inspection for up to two years after the termination of the lease (Mass. Gen. Laws Ann. Ch 186, Section 15B(2)(d)). 
Michigan One and a half months' rent (Mich. Comp. Laws 554.602). Notice to tenant must be provided within 14 days of tenant taking possession. Notice must include landlord's name, address for communication, financial institute/surety where deposit is held, and tenant's obligation to provide a forwarding address in writing to the landlord within four days after termination of the tenancy in order to have deposit returned. Exact wording in 12-POINT BOLDFACE TYPE THAT IS AT LEAST 4 PTS LARGER THAN THE BODY OF THE NOTICE/LEASE AGREEMENT: "You must notify your landlord in writing within four days after you move of a forwarding address where you can be reached and where you will receive mail; otherwise your landlord shall be relieved of sending you an itemized list of damages and the penalties adherent to that failure" (Mich. Comp. Laws 554.602). Nonrefundable fees permitted (Stutelberg v Practical Management Co. 245 N.W. 2d 737 (1976)).
Minnesota No limit under state law (note that cities and counties may impose their own limits on security deposits)
Mississippi No limit under state law (note that cities and counties may impose their own limits on security deposits)
Missouri Two months' rent (Mo. Rev. Stat. 535.300.1)
Montana No limit under state law (note that cities and counties may impose their own limits on security deposits)
Nebraska One month's rent (excluding pet deposit). Pet deposits are capped at one quarter month's rent (Neb. Rev. Stat 76-1416(1)). 
Nevada Three months' rent. Landlord may use surety bond for all or part of the deposit (Nev Rv. Stat. 118A.242(1)).
New Hampshire May not exceed one month's rent or $100, whichever is greater (RSA 540-A:6). Landlord MUST provide a receipt stating the security deposit amount and the place where the deposit will be held (RSA 540-A:6(I)(b)).
New Jersey One and a half month's rent (NJSA 46:8-21.2). Any additional security deposit collected annually (to make up for rent increase) may be no greater than 10% of current security deposit (NJSA 46:8-21.2).
New Mexico One month's rent maximum for rental agreements of less than one year. No deposit limit if lease is one year or longer in duration (N.M. Stat Ann 47-8-18(A)(2)). If security deposit is greater than one month's rent, landlord must pay interest on an annual basis equal to passbook interest (N.M. Stat Ann 47-8-18(A)(1)).
New York No limit under state law (note that cities and counties may impose their own limits on security deposits)
North Carolina Two months' rent for terms greater than month-to-month rentals; two weeks' rent for week-to-week rentals; one and a half months' rent for month-to-month rentals (NC Gen Stat 42-51(b)). Pet deposits must be reasonable and nonrefundable (NC Gen Stat 42-53).
North Dakota One month's rent (ND Century Code 47-16-07.1(1)). Additional pet deposit capped at $2,500 or two months' rent, whichever is greater. The landlord cannot charge pet deposit for service animals or companion animals in ADA accommodation (ND Century Code 47-16-07.1(2)).
Ohio No limit under state law (note that cities and counties may impose their own limits on security deposits)
Oklahoma No limit under state law (note that cities and counties may impose their own limits on security deposits)
Oregon No limit under state law (note that cities and counties may impose their own limits on security deposits). No pet deposit may be charged for service or companion animals required for tenants with a disability (reasonable accommodation under fair housing laws).
Pennsylvania Two months' rent during the first year of the lease (68 PS 250.511a(a)); one month's rent during the second year and any subsequent years of lease/renewal (68 PS 250.511a(b) and (c)).
Rhode Island One month's rent (RI Gen laws 34-18-19(a))
South Carolina No limit under state law (note that cities and counties may impose their own limits on security deposits)
South Dakota One month's rent, except where special conditions pose a danger to maintenance of the premises (SD Codified Laws 43.32-6.1)
Tennessee No limit under state law (note that cities and counties may impose their own limits on security deposits)
Texas No limit under state law (note that cities and counties may impose their own limits on security deposits)
Utah No limit under state law (note that cities and counties may impose their own limits on security deposits)
Vermont No limit under state law (note that cities and counties may impose their own limits on security deposits)
Virginia Two months' rent (VA code 55-248.15:1(A))
Washington No limit under state law (note that cities and counties may impose their own limits on security deposits)
West Virginia No limit under state law (note that cities and counties may impose their own limits on security deposits)
Wisconsin No maximum limit is set by state law. However, note that a "security deposit" is defined as anything in excess of one month's prepaid rent (ATCP 134.02(11)), so anything collected outside of rent must be treated as a security deposit.
Wyoming No maximum limit is set by state law. However, the landlord must disclose in writing any portion of any deposit that is nonrefundable (Wyo Stat 1-21-1207).