New Mexico's security-deposit rules look simple on the surface, one month's rent, return it in 30 days, but the details are where landlords and property managers get tripped up. The one-month deposit rule applies to rental agreements lasting less than one year; annual rental agreements do not have a stated fixed dollar cap under § 47-8-18, but the deposit must still be reasonable, and a deposit exceeding one month's rent triggers an annual interest obligation. And missing the 30-day return deadline can forfeit the owner's right to retain the deposit and expose the owner to fees and other liability. Getting the mechanics right is what separates a clean move-out from a small-claims loss.

All of it lives in a single statute: Section 47-8-18 of the New Mexico Statutes Annotated, part of the Uniform Owner-Resident Relations Act (UORRA). This guide walks through what that statute actually requires, the deposit rule and when it applies, the interest requirement for annual leases, the 30-day itemized-return deadline, what can and can't be deducted, and the specific penalties for noncompliance, so a property manager can build a deposit process that holds up.

Quick answer: Under NMSA Section 47-8-18, a New Mexico security deposit must be reasonable. For a rental agreement with a duration of less than one year, the deposit may not exceed one month's rent. For an annual rental agreement, Section 47-8-18 does not state a fixed dollar cap, but the deposit must still be reasonable, and if it exceeds one month's rent, the owner must pay the resident annual interest using the statute's passbook-rate language (see the interest section below, that language refers to a now-defunct federal agency and may need current legal interpretation). When the tenancy ends, if the owner intends to retain any part of the deposit, the owner must give the resident an itemized written statement of deductions and any balance within 30 days of termination or the resident's departure, whichever is later. Normal wear and tear can't be deducted. Miss the 30-day deadline and the owner can forfeit the right to withhold any part of the deposit and become liable for court costs and attorney's fees; a bad-faith retention adds a $250 civil penalty.

Key takeaways

• New Mexico's security-deposit rules are set by NMSA Section 47-8-18, part of the Uniform Owner-Resident Relations Act.

• For a rental agreement with a duration of less than one year, the deposit is capped at one month's rent.

• For an annual rental agreement, § 47-8-18 does not state a fixed dollar cap, but the deposit must still be reasonable, and a deposit above one month's rent triggers the statute's annual interest provision.

• The statute's interest provision uses historical Federal Home Loan Bank Board passbook-rate language; because that agency was abolished, the applicable rate may need current legal or regulatory interpretation.

• The deposit must be reasonable, and normal wear and tear can never be deducted.

• If the owner retains any deposit, the owner must send an itemized written statement of deductions and any balance within 30 days of termination or the tenant's departure, whichever is later.

• Missing the 30-day deadline can forfeit the right to keep any of the deposit and expose the owner to court costs and attorney's fees; a bad-faith retention adds a $250 civil penalty.

The deposit rule: one month's rent (on leases under a year)

Short answer: for a rental agreement of less than one year, the deposit can't exceed one month's rent; annual rental agreements follow a different rule.

This is the part most people simplify incorrectly. New Mexico's one-month rule is not universal, it's tied to the length of the rental agreement.

• Rental agreements of less than one year. Under Section 47-8-18(A)(2), for a rental agreement with a duration of less than one year, the owner may not demand or receive a deposit greater than one month's rent. This is the flat cap most tenants are thinking of.

• Annual rental agreements. For an annual rental agreement, Section 47-8-18 does not state a fixed dollar cap, but the deposit must still be reasonable, and a deposit above one month's rent triggers the statute's interest provision. Under Section 47-8-18(A)(1), if the owner demands or receives a deposit greater than one month's rent, the owner must pay the resident annual interest on the deposit under the statute's passbook-rate language (discussed below).

In every case, the deposit must be reasonable, even where the statute does not state a fixed dollar cap. An unusually large deposit creates litigation and compliance risk, so managers should obtain legal advice before charging substantially more than one month's rent.

The practical read: on an annual rental agreement, an owner who wants to hold more than a month's rent as a deposit takes on an ongoing obligation to calculate and pay the tenant interest every year, which is why many keep the deposit at one month even where a higher amount would be permitted.

The interest rule on annual leases

Short answer: on an annual rental agreement, a deposit above one month's rent triggers a statutory interest obligation, but the rate reference is historical and may need legal interpretation.

The interest requirement is New Mexico's distinctive wrinkle, and it comes with a catch. For an annual rental agreement, if the deposit exceeds one month's rent, Section 47-8-18 requires the owner to pay annual interest using the statutory passbook-rate language. That language refers to a historical Federal Home Loan Bank Board rate, and that agency was abolished, so the reference may require current legal or regulatory interpretation. The deposit itself doesn't have to sit in a separate interest-bearing account, but the interest obligation still attaches to a deposit above one month's rent on an annual agreement.

Because the rate reference is outdated, property managers should not assume there's a simple, readily calculable current figure. Verify the applicable rate and payment method with New Mexico counsel before collecting more than one month's rent on an annual rental agreement. Practically, that uncertainty is one more reason many owners keep the deposit at one month, where the interest provision never comes into play.

The 30-day return deadline and itemization

Short answer: if the owner intends to retain any deposit, the owner must send an itemized statement and any balance within 30 days of termination or the tenant's departure, whichever is later.

When the tenancy ends, the owner may apply the deposit to unpaid rent and to damages the owner suffered because of the resident's noncompliance. But the return process is governed by a firm deadline in Section 47-8-18(C):

If the owner intends to retain any portion of the deposit, the owner must provide the resident with an itemized written statement of the deductions and any balance within 30 days after the later of termination of the rental agreement or the resident's departure. The owner is treated as complying by mailing the statement and any payment due to the resident's last-known address.

Two points matter here. First, the clock runs from the later of lease termination or actual departure, not automatically from the lease-end date. Second, the itemization requirement is triggered when the owner retains part of the deposit; the safest practice is always to send a written accounting, because the consequence for skipping it is severe.

What can and can't be deducted

Short answer: deposits cover unpaid rent and damages from the resident's noncompliance, but never normal wear and tear.

The statute is explicit that no deposit may be retained to cover normal wear and tear. An owner may apply the deposit to unpaid rent and damages the owner suffered because of the resident's noncompliance with the rental agreement or Section 47-8-22. Normal wear and tear may not be charged against the deposit. Ordinary aging of the unit, such as carpet wear from normal use, minor scuffs, or faded paint, is the owner's cost, not the resident's.

This is one of the most common sources of deposit disputes, because the line between "damage" and "wear and tear" is a judgment call. The owner's protection is documentation: dated move-in and move-out condition records that show a specific problem was tenant-caused, not the ordinary passage of time. Without that, a contested deduction is hard to defend.

The penalty for getting it wrong

Short answer: missing the 30-day deadline can forfeit the deposit and add attorney's fees; a bad-faith retention adds a $250 penalty.

New Mexico backs the return deadline with real teeth, and the consequences come in two distinct layers that are easy to confuse.

First, under Section 47-8-18(D), if the owner fails to provide the written statement of deductions and the balance due within 30 days of termination, the owner:

• Forfeits the right to withhold any portion of the deposit;

• Forfeits the right to assert any counterclaim in an action brought to recover the deposit;

• Becomes liable to the resident for court costs and reasonable attorneys' fees; and

• Forfeits the right to bring an independent action against the resident for damages to the property.

That is a severe statutory consequence when the deadline violation is established: the owner can lose the entire deposit and end up paying the tenant's legal costs, even if there was genuine damage, because the right to pursue it is forfeited.

Second, and separately, under Section 47-8-18(E), an owner who in bad faith retains a deposit in violation of the section is liable for a $250 civil penalty payable to the resident. This penalty is tied to bad-faith retention specifically, it's an additional consequence, separate from the forfeiture that flows from missing the deadline.

For a property manager, the lesson is unforgiving but simple: the 30-day itemized return isn't a best practice, it's a hard deadline whose miss can wipe out the deposit and add fees.

The operational read for property managers

For a property manager, New Mexico deposits are a documentation-and-deadline exercise. Almost every risk in Section 47-8-18 comes down to two things: collecting a defensible amount at move-in, and returning the deposit correctly and on time at move-out.

Build the process around the statute. At lease signing, set the deposit with the lease term in mind: one month's rent keeps a short lease cleanly within the rule and avoids the interest provision entirely, and a good tenant screening and lease-setup workflow is where that decision belongs. During the tenancy, if you've collected more than a month on an annual rental agreement, remember the statute's interest obligation attaches (and verify the applicable rate with counsel, given the outdated rate reference). At move-out, treat the 30-day clock as the priority: document the unit's condition, separate genuine damage from normal wear and tear, prepare the itemized statement, and mail the statement and any balance to the tenant's last-known address inside the window.

Two habits carry most of the weight. First, condition documentation: dated move-in and move-out records, backed by a consistent property inspection and maintenance process, are what let you defend a deduction as actual damage rather than wear and tear. Second, clean deposit accounting: tracking each deposit, any interest owed, and the deductions through a reliable rent and payments record is what lets you produce an accurate itemized statement inside the 30-day window and show you met the deadline if the return is ever challenged.

Common mistakes checklist

• Charging more than one month's rent as a deposit on a rental agreement of less than one year

• Collecting more than one month's rent on an annual lease without verifying and paying the interest required by § 47-8-18

• Assuming the one-month rule applies to every lease (it's specific to agreements under a year)

• Assuming there's a simple, readily calculable current interest rate (the statute's rate reference is outdated and may need legal interpretation)

• Deducting for normal wear and tear, which the statute prohibits

• Missing the 30-day deadline to send the itemized statement and balance (measured from termination or departure, whichever is later)

• Sending the balance without an itemized written statement of deductions

• Assuming a genuine-damage claim survives a missed deadline (the right to pursue it is forfeited)

• Confusing the forfeiture (missed deadline) with the separate $250 bad-faith penalty

• Failing to keep dated move-in and move-out condition records to support deductions

Frequently asked questions

1. How much can a landlord charge for a security deposit in New Mexico?
It depends on the lease length. Under NMSA Section 47-8-18, for a rental agreement with a duration of less than one year, the deposit can't exceed one month's rent. For an annual rental agreement, § 47-8-18 does not state a fixed dollar cap, but the deposit must still be reasonable, and a deposit above one month's rent triggers the statute's interest provision (the owner must pay the tenant annual interest under the passbook-rate language).

2. Does a New Mexico landlord have to pay interest on a security deposit?
Sometimes. On an annual rental agreement, if the deposit is greater than one month's rent, Section 47-8-18 requires the owner to pay the resident annual interest using the statute's passbook-rate language. That language refers to a historical Federal Home Loan Bank Board rate, and because that agency was abolished, the applicable rate may require current legal or regulatory interpretation, so verify it with New Mexico counsel. If the deposit is one month's rent or less, no interest is required.

3. How long does a landlord have to return a security deposit in New Mexico?
If the owner intends to retain any part of the deposit, the owner must provide an itemized written statement of deductions and any balance within 30 days after the later of termination of the rental agreement or the resident's departure. Mailing the statement and any payment to the tenant's last-known address satisfies the requirement.

4. What happens if a New Mexico landlord doesn't return the deposit on time?
Under Section 47-8-18(D), an owner who fails to provide the written statement and balance within 30 days forfeits the right to withhold any portion of the deposit, forfeits the right to assert a counterclaim in an action to recover it, forfeits the right to bring an independent action for property damage, and becomes liable to the tenant for court costs and reasonable attorneys' fees. Separately, an owner who retains a deposit in bad faith is liable for a $250 civil penalty.

5. Can a landlord deduct for normal wear and tear in New Mexico?
No. The statute expressly prohibits retaining any part of the deposit to cover normal wear and tear. Deposits may be applied to unpaid rent and damages the owner suffered because of the resident's noncompliance with the rental agreement or Section 47-8-22, but ordinary aging of the unit is the owner's cost. Dated move-in and move-out records are the best way to show a specific problem was damage rather than wear and tear.

6. Is the $250 penalty automatic if the landlord is late?
Not exactly. The $250 civil penalty under Section 47-8-18(E) applies to an owner who retains a deposit in bad faith. The consequences of missing the 30-day deadline, forfeiting the deposit and becoming liable for court costs and attorney's fees, come from Section 47-8-18(D) and are separate from the bad-faith penalty.

7. Does the deposit have to be kept in a separate account in New Mexico?
Section 47-8-18 does not itself state a general separate-account or escrow requirement. For an annual rental agreement with a deposit above one month's rent, the statute separately requires annual interest under its historical passbook-rate language, so tracking that obligation (and confirming the applicable rate) is important.

This article is for general informational purposes and is not legal advice. Security-deposit rules can be affected by the specific lease, local ordinances, and case law, and statutes change; confirm current requirements with a New Mexico attorney or the applicable court before acting. The requirements above come from the New Mexico Uniform Owner-Resident Relations Act, principally the deposit statute at NMSA Section 47-8-18.