Illinois and California sit at opposite ends of American security deposit law. One sets no limit on what a landlord may collect and pays interest that rounds to nothing. The other limits the deposit to a single month and, in San Francisco, pays a rate more than four hundred times higher. Anyone who owns property in both states, or who moves between Chicago and the Bay Area, is dealing with two systems that agree on very little.
This article sets out the differences using figures from the Homzora open datasets for Illinois and Chicago, together with California research verified on 18 September 2026. Where we have not verified something to the standard we apply everywhere else, we say so rather than filling the gap.
The cap: nothing against one month
Illinois sets no statutory limit on the size of a residential security deposit. Neither does Chicago. A landlord may ask for whatever the market will support, and in a competitive building that can mean first month, last month and a deposit on top. The only constraint is what a prospective tenant is willing and able to pay.
California limits the deposit to one month of rent. That limit applies whether the unit is furnished or unfurnished, which is itself a recent change. For many years California drew a distinction between the two and allowed more for a furnished unit. That distinction is gone.
The practical consequence for an Illinois owner expanding into California is that a familiar lever simply disappears. You cannot price risk through the deposit. If a tenant presents as marginal on credit or income, the deposit is not where you address it, because the ceiling is fixed by statute and does not move for a weaker applicant.
The small landlord exception, and how narrow it really is
California permits two months rather than one, but only in a tightly drawn set of circumstances, and the wording matters.
The landlord must be a natural person, or a limited liability company in which every member is a natural person. The landlord must own no more than two residential rental properties. Those properties must contain no more than four dwelling units in total.
Read that as a set of conditions that must all hold at once, because that is how it operates. An investor holding three small properties does not qualify, even if the total unit count is low. A corporation does not qualify regardless of size. An LLC with a single corporate member does not qualify, because the members are not all natural persons.
There is a further restriction on top. The higher deposit may not be demanded from a servicemember, whatever the ownership structure looks like. A landlord who otherwise qualifies for the two month deposit still cannot apply it to a tenant covered by that protection.
Illinois has no equivalent structure for the simple reason that it has no cap to make exceptions to.
The return deadline: 45 days against 21
Chicago gives a landlord forty five days from the end of the tenancy to return the deposit, and thirty days to provide an itemized statement of any damages claimed. Illinois state law requires the itemized statement within thirty days and full return within forty five where no statement is given.
California requires the deposit back within twenty one days.
That is a difference of twenty four days, and it changes how the work has to be organised. Forty five days is long enough to get a contractor in, obtain a written quote and base a deduction on a real invoice. Twenty one days often is not. A California landlord who waits for a tradesperson to return a call is at serious risk of missing the deadline, which means the inspection and the costing have to begin on the day the keys come back rather than in the week after.
What Chicago adds on top of Illinois
A Chicago tenancy is subject to both the state statute and the city ordinance, and the two do not say the same thing. Where they differ, the city rules govern inside Chicago, which is why our Chicago datasets publish both sets of figures side by side rather than picking one.
The Residential Landlord and Tenant Ordinance requires a receipt at the point the deposit is taken. It requires a summary of the interest rate to be attached to the lease. It requires the itemized damages statement. These are procedural obligations that attach to documents rather than to money, and they are the ones most often missed by an owner who has read the state statute and stopped there.
Interest: the difference is a factor of four hundred
This is the single largest gap between the two systems and it is the one least likely to appear in a comparison built on rent alone.
Chicago requires a landlord to pay annual interest on the deposit at a rate the City Comptroller publishes each year. For 2026 that rate is 0.01 percent. On a two thousand dollar deposit held for a year, the tenant is owed twenty cents.
Illinois separately requires interest, but only at buildings of twenty five units or more. Below that threshold the state obligation does not apply, though the Chicago obligation still does inside the city.
San Francisco requires interest at a rate the city publishes annually. For the period running from 1 March 2026 to 28 February 2027 that rate is 4.2 percent. On the same two thousand dollar deposit held for a year, the tenant is owed eighty four dollars.
Twenty cents against eighty four dollars, on an identical deposit, for an identical period. The obligation exists in both cities and is described in almost identical language. Only the number differs, and it differs by a factor of more than four hundred.
For a portfolio this stops being trivia and becomes a line in the accounts. Fifty units in San Francisco, each holding a two thousand dollar deposit, generates an annual interest liability of several thousand dollars that has to be tracked, accrued and paid. The same portfolio in Chicago generates ten dollars.
Penalties, and one figure we will not state
Chicago exposes a landlord who gets the deposit wrong to damages of twice the deposit. Illinois applies the same multiple. That exposure attaches to a range of failures rather than to a single one, which is why the procedural obligations above are worth taking seriously even where the sums involved look small.
We are not going to state a California penalty figure here.
California does provide for damages where a landlord retains a deposit in bad faith, and the six city comparison we publish leaves that cell deliberately empty. The sources we checked did not agree closely enough for us to publish a number, and a penalty figure is exactly the sort of thing a reader would rely on. An empty cell means we have not verified it, not that no penalty exists. Treat the exposure as real and check the current provision before relying on any specific multiple.
Rent control sits behind all of this
The deposit rules do not exist in isolation, and the wider posture of each state explains a good deal about them.
Illinois preempts rent control statewide. No Illinois municipality, Chicago included, may impose it. The deposit is uncapped, the rent is uncapped, and the tenant protections that do exist are procedural rather than financial.
California runs the opposite way. San Francisco caps annual increases on covered units at 1.6 percent for the period from 1 March 2026 to 28 February 2027. The deposit is capped, the rent increase is capped on covered stock, and the obligations are financial as well as procedural.
An owner moving between the two is not adjusting to a different rule. They are adjusting to a different philosophy, and the individual rules follow from it.
Late rent moves at a different speed too
Chicago gives a tenant a ten day right to cure before a tenancy can be ended for unpaid rent.
California serves a three day notice, and the counting is not what it appears. The three days exclude Saturdays, Sundays and judicial holidays. A notice served on a Thursday before a holiday weekend does not expire on the Sunday. Counting those as plain calendar days is the most common error in published guidance on California notice periods, and it produces a defective notice rather than a fast eviction.
If you own in both states
Treat them as separate operations rather than one portfolio with two addresses. The deposit ceiling, the return clock, the interest rate and the notice arithmetic all differ, and a process built for one will fail quietly in the other.
The specific traps worth naming: do not carry an Illinois deposit schedule into California, because the ceiling is fixed. Do not carry a California return process into Chicago, because the paperwork obligations are heavier. Do not assume interest is negligible because it is negligible in Chicago. And do not count California notice days on a calendar.
What we are not claiming
This article compares statutory and municipal rules. It does not compare rents between the two states, because our rent data does not meet the same standard in every city we cover and subtracting one average from another would produce a number that looks authoritative and is not.
Nothing here is legal advice, and the California penalty figure is genuinely open rather than merely omitted.
Disclosure: the lease document link below is an affiliate link. If you use it we may earn a commission at no additional cost to you. It does not affect what we publish.
LawDepot lease agreements covers both states. For a specific tenancy or a specific ownership structure, consult an attorney licensed where the property is.
The data behind this article
The Illinois and Chicago figures come from the Chicago edition datasets. The San Francisco figures come from the San Francisco edition and from research verified on 18 September 2026.
The cross city statutory comparison covering all six cities we publish is available as CSV or JSON under CC BY 4.0. Empty cells are documented rather than hidden.
Verified 18 September 2026. Homzora is not a licensed real estate brokerage, property manager or law firm, and nothing here is legal advice.
