Connecticut landlord compliance guide: deposits, interest, late fees

Connecticut regulates the deposit, its interest, the late fee, and the return clock — and enforces mistakes with statutory damages. Here is what the law expects and what Stonerow does about it, question by question.

How much can a landlord charge for a security deposit in Connecticut?

Two months' rent — one month if the tenant is 62 or older (Conn. Gen. Stat. §47a-21). Stonerow enforces the cap when the lease is saved; an over-cap deposit cannot be entered.

Do Connecticut landlords have to pay interest on security deposits?

Yes. Connecticut sets a deposit-interest rate annually through a published index (for example, 0.49% for 2026). Stonerow calculates per lease using the state index — on demand on Core, accrued automatically on Standard.

What is the late-fee limit in Connecticut?

Residential late fees are limited by statute — commonly summarized as the lesser of $50 or 5% of the overdue rent, after a statutory grace period (§47a-15a). Every Stonerow assessment is clamped to the limit before it posts, manual or automated.

How long does a Connecticut landlord have to return a deposit?

Generally the later of 21 days after the tenancy ends or 15 days after receiving the tenant's forwarding address, with an itemized statement (§47a-21). Wrongful withholding can cost twice the amount withheld. Stonerow generates the statute-cited itemization PDF — see the guide.

How much notice for a rent increase in Connecticut?

Recent Connecticut law requires advance written notice of rent increases — 45 days or more in covered situations (Public Act 24-143).

General information, not legal advice. Statutes change — verify current law with counsel. Product view: Stonerow for Connecticut landlords.

Why Connecticut's deposit rules carry real financial risk

Connecticut pairs a hard deposit ceiling with an interest obligation and a return clock, and it attaches statutory damages when a landlord gets them wrong. The exposure is not the deposit itself but the multiplier: wrongful withholding can cost twice the amount withheld, which turns a disputed $1,500 deposit into a $3,000 judgment plus the time spent defending it. That asymmetry is why the cap is enforced when the lease is saved rather than flagged in a report afterwards — a deposit that never got collected over the limit cannot become that case.

The interest index changes every year

Connecticut publishes a deposit-interest rate annually, so a rate memorised in one year is wrong the next. Stonerow calculates per lease using the state's index, which removes the most common quiet failure: an owner who correctly paid interest for three years using a rate that stopped being current in year two. On Core you run the accrual on demand; on Standard it accrues on schedule. Either way the calculation is the same and it is never gated behind a paid plan.

What to do when a tenancy ends

Generate the itemization statement rather than writing a letter from scratch. It prints with the statutory citation on the page, lists deductions against the deposit, and includes the accrued interest the system has been tracking. Send it inside the statutory window with the refund. The append-only ledger behind it means the arrears you are deducting for are evidenced by dated entries rather than reconstructed from memory, which is the difference between a defensible deduction and a contested one.