Most landlords treat unpaid rent as a simple debt. The tenant owes the money, so the court will order them to pay it. In practice, a surprising number of arrears claims collapse not on the facts but on technicalities the landlord never realised applied to them. The rent is plainly owed, the tenant has plainly not paid, and yet the claim still fails.

Since the Renters' Rights Act 2025 took full effect on 1 May 2026, those technicalities carry more weight than ever. Section 21 is gone, and every possession claim now rests on Section 8 grounds. Courts examine compliance closely, and a single missed step can leave rent legally unrecoverable no matter how clear the underlying debt is. The good news is that all of these requirements are within any landlord's control, provided they are dealt with early rather than discovered halfway through a claim.

Rent is not always legally due, even when it is owed

This is the requirement that catches the most landlords out. Under Section 48 of the Landlord and Tenant Act 1987, a landlord must give the tenant, in writing, an address in England or Wales at which notices can be served. Until that address is provided, any rent otherwise due is treated as not legally payable.

The debt does not disappear. It remains owed in principle, but it cannot be enforced through the courts until a valid address for service is in place. A landlord who has never satisfied this requirement can find an entire arrears claim stalled at the first hurdle, with the rent only becoming recoverable once the position is corrected.

Many landlords assume their tenancy agreement already covers this, and a well drafted agreement often does. The problem arises when the agreement omits an address, gives only an email address or a PO box, or names an address that has since changed because the landlord moved or switched agents. The address must be a genuine physical location in England or Wales, which is why serving a valid Section 48 notice properly, with the right form of words and proof that it reached the tenant, is worth getting right at the start of every tenancy.

Rent demands carry their own rules

Section 47 of the same Act sits alongside Section 48 and is just as easy to overlook. Any written demand for rent or service charges must include the landlord's name and address. Where the landlord's address is outside England or Wales, the demand must also give an address within England or Wales for the service of notices. A demand that fails to meet this requirement does not make the charge payable until the position is corrected.

In practice, a landlord who states their name and a valid address on the tenancy agreement usually satisfies both Section 47 and Section 48 at once. The risk lies in informal arrangements, where rent is requested by text message or email with no proper paperwork behind it, and the landlord later struggles to show that the sums were ever lawfully demanded.

Deposit handling can hand the tenant a counterclaim

A landlord who has not protected the deposit in an authorised scheme, or who failed to serve the prescribed information within the statutory window, exposes themselves to a penalty of between one and three times the deposit. A tenant facing an arrears claim will often raise this as a counterclaim, and the resulting award can wipe out a meaningful part of the rent the landlord is trying to recover.

Protecting the deposit promptly and keeping the scheme certificate and prescribed information on file removes this line of defence entirely. It is a straightforward step that closes off a common and costly counterclaim before it can be made.

Your records decide the case

An arrears claim succeeds or fails on the evidence the landlord can produce. A clear rent account showing what was due, what was paid, and what remains outstanding is the foundation. Alongside it, a landlord needs the signed tenancy agreement, proof that compliance documents were served, and a record of any correspondence about the arrears.

Where this paperwork is incomplete, the landlord ends up reconstructing it under pressure, often from memory, and a tenant who disputes the figures can introduce just enough doubt to slow or derail the claim. Keeping organised records throughout the tenancy, rather than assembling them once a problem arises, is the single most reliable way to protect a claim. Sound record keeping also makes it far easier to show the court that every statutory step was taken at the right time.

The notice and the ground must match the new regime

With Section 21 abolished, possession on the basis of rent arrears now depends on Section 8 and the correct ground. The serious rent arrears grounds remain available, but the thresholds and notice periods must be applied as they now stand, and the notice itself must be accurate. A notice that cites the wrong ground, states the arrears incorrectly, or gives the wrong notice period invites a challenge that can send the landlord back to the start.

Because every possession claim now runs through Section 8, the margin for error has narrowed. A landlord who would once have relied on the no-fault route now has to get the fault-based process exactly right, which makes the earlier compliance points all the more important. A claim built on a clean rent account, valid notices, and a properly served address for service is far harder to resist.

Getting compliance in order before you need it

None of these requirements is difficult on its own. The difficulty comes from discovering them at the point of crisis, when the tenant is already in arrears and the time to put things right has largely passed. A landlord who confirms the address for service at the start of every tenancy, protects deposits promptly, demands rent correctly, and keeps a tidy account is rarely caught out by a technicality.

The cost of getting this wrong is not the loss of the debt, which usually still exists in principle, but the loss of the practical ability to enforce it. Treating compliance as routine groundwork rather than emergency repair is what keeps a winnable claim winnable.