Storage unit rental contract: what it must contain (and what gets forgotten)

You have found a storage unit to rent, the owner sends you a ready contract to sign, and it looks solid, because it has all the standard points: the parties, the rent, the deposit.

The problem is that even lawyers writing on the subject admit such contracts regularly lack the clauses that actually protect you when something goes wrong: flooding, theft, a dispute over what may be kept inside.

Below you will find everything that has to be in there. The article describes Polish practice, because that is where the listings on Maszbox.pl are located.

Mandatory elements of a storage unit rental contract

Whether the landlord drafts the contract or you download a ready template, it should contain:

• the date and place it was drawn up, and the full details of both parties,
• a precise description of the space: address, unit number and floor area, not just a storage unit in the basement,
• the term, meaning fixed period or indefinite,
• the amount of rent, the payment date and the payment method,
• the rules for using the space,
• the deposit clauses: the amount and the conditions for returning it,
• the signatures of both parties.

Missing any of these points does not automatically invalidate the contract, but it does make pursuing a claim considerably harder if a dispute arises.

Prohibited items - what most contracts stay silent about

This is a point missing from most ready templates available online, and it is worth adding, because it bears directly on the safety of the whole building, not just your unit. House rules and rental contracts for this type of space typically prohibit storing:

• flammable and explosive materials - fuels, gas cylinders, large quantities of solvents,
• toxic substances and chemicals in containers that are not sealed,
• perishable food - it attracts pests, which affects the neighbouring units as well.

The exact list depends on the house rules of the specific building and the fire safety regulations that apply to it. If the contract you received says nothing about this, ask the landlord directly before you put anything inside.

Who is liable for damage, flooding and theft?

This is the second thing lawyers writing about storage unit contracts point to as commonly skipped. The general rule: the landlord is liable for the technical condition of the space itself, meaning it being watertight, secured and free of structural faults, while the tenant is liable for their own belongings inside. This has to be stated explicitly in the contract, otherwise each side will fall back on a different interpretation in a dispute.

Check as well whether your home insurance policy actually covers items kept in a rented unit rather than one you own. That is not always obvious, so verify it with your insurer before signing rather than after a loss.

Notice period and deposit - what to watch out for

The contract should clearly set out the notice period, typically one to three months for indefinite contracts, and the conditions under which the deposit is returned: how soon after the tenancy ends and what can reduce it, for example unpaid rent or damage to the space.

The absence of a specific deadline for returning the deposit is one of the most common causes of disputes in this kind of tenancy. If you want to know whether the proposed rent and deposit are in line with the market, check how much renting a storage unit costs in 2026.

Technical condition - what to check before signing

Before you sign anything, view the unit in person: no damp, water stains or traces of mould on the walls, a working lock and door, access to light if there is an electrical installation, and the general cleanliness of the corridor leading to the space. It is worth photographing the initial condition - that is your protection when the deposit is returned.

Does Maszbox act as an intermediary? What you handle yourself

Maszbox.pl is a listings service - it connects the parties, but it is not a party to the rental contract and does not draft it. Everything to do with the rent, the deposit, the term and the scope of liability you negotiate directly with the landlord, using the contact details from the listing.

That is exactly why it is worth going through the points in this article yourself before signing - no platform will do it for you. Current offers are on the list of storage units for rent, and if you are the one with a free unit, the publishing rules are described on the how to add a listing page.