Section 21 Is Dead. Here's What HMO Landlords Got Wrong.

What Actually Changed on 1 May 2026

The Renters' Rights Act 2025 received Royal Assent on 27 October 2025, according to The Independent Landlord and thehmoagent.com. The headline provision — abolition of Section 21 'no-fault' evictions — came into force on 1 May 2026. That's the date most landlords know. What far fewer understood is what replaced the old tenancy structure underneath it.

From 1 May 2026, all assured shorthold tenancies (ASTs) were abolished. Every tenancy in your HMO is now a rolling assured periodic tenancy — by default, month-to-month. There are no more fixed terms. You cannot write a 12-month AST and rely on the end date as your exit route. That mechanism is gone.

For single-let landlords this is significant. For HMO operators, it's a different level of complexity entirely — because each individual room in your HMO now carries its own rolling periodic tenancy. RealYield and the NRLA both flagged this: the new regime applies to individual tenancies within HMOs, not to the property as a whole. That means if you have six rooms, you have six separate rolling periodic tenancies, each requiring its own possession route if things go wrong.

The 31 July 2026 Deadline Most Landlords Missed

Here's where it gets painful for anyone who served a Section 21 notice before 1 May 2026 and thought they were safe.

According to The Independent Landlord, transitional provisions allowed old Section 21 notices served before the commencement date to remain valid — but only if possession proceedings were issued by the earlier of: six months from the date of the notice, or three months from 1 May 2026. Three months from 1 May 2026 is 31 July 2026.

That date has passed.

If you served a Section 21 notice before 1 May 2026 and hadn't issued court proceedings by 31 July 2026, that notice is now worthless. You cannot rely on it. You cannot re-serve it. Section 21 no longer exists. You must start again using Section 8 — and that means building a case on one of the statutory grounds. If you don't have grounds, you wait until you do.

I've spoken to landlords who genuinely believed their pre-May notice gave them a clean runway. It didn't. The transitional window closed. This is the single biggest operational mistake I'm seeing across HMO operators right now, and it's entirely avoidable with the right information.

Section 8: Your Only Tool Now — And How It Actually Works

Section 8 has always existed, but most landlords treated it as a last resort — messy, contested, slow. That attitude has to change, because it's the only route you have.

Under the new regime, the grounds that matter most for HMO operators are:

Ground 8 — Rent Arrears. This is the mandatory ground. But the threshold has moved. Under the Renters' Rights Act, Ground 8 now requires three months' arrears at both the point of serving the notice AND at the point of the court hearing. Previously, two months was sufficient. The notice period is four weeks. The critical trap here is the 'at hearing' requirement: if a tenant pays down enough arrears between your notice and the hearing date to drop below the three-month threshold, the court cannot grant possession on Ground 8. The arrears must be sustained. This is not theoretical — it happens regularly in practice.

Ground 1 — Landlord or Family Occupation. You intend to move into the property, or a close family member does. The notice period is four months. This ground is mandatory once the conditions are met, but 'close family member' has a defined legal meaning — consider consulting a qualified solicitor before relying on it.

Ground 1A — Intent to Sell. You intend to sell the property with vacant possession. Again, four months' notice, and the intention must be genuine and demonstrable. Courts have discretion to scrutinise this.

Ground 7A — Anti-Social Behaviour. This is the one ground that can move fast. For serious ASB, the notice period can be immediate. But the evidential bar is high — documented incidents, police involvement, formal warnings. You need a paper trail from day one.

Student HMO Ground — This is new and specifically relevant to HMO operators. Where all occupants are full-time students and you intend to re-let to students, there is a new mandatory ground available. If you run a student HMO and weren't aware of this, it changes your end-of-year planning significantly. RealYield flagged this as one of the most underreported provisions in the Act.

The Tenant's New Exit Power — And Why It Shifts Your Risk Profile

One provision that's received almost no coverage in the HMO-specific press: tenants can now leave with two months' notice, regardless of when they moved in, according to Citywide Housing's analysis of the Act.

In a single let, this is manageable. In an HMO with six rooms on rolling periodic tenancies, this creates a void-stacking risk that didn't exist before. A tenant who moves in during October can serve notice in December and be gone by February — right in the middle of your void season. You have no fixed-term buffer. No break clause to negotiate around. Two months and they're out.

The practical implication: your HMO's income model needs to account for higher turnover probability, and your void-cost assumptions from 2024 may be materially wrong. If you're stress-testing your HMO deals on old tenancy assumptions, you're underpricing the risk.

This is also why possession strategy and deal evaluation are now the same conversation. You can't assess whether an HMO stacks up financially without understanding the possession and tenancy exposure underneath it.

What HMO Operators Should Do Right Now

Audit your current tenancies. For every room in every property, establish: when the tenancy started, whether any Section 21 notice was ever served (and if so, whether proceedings were issued before 31 July 2026), and whether you have any documented grounds for Section 8 if needed.

If you served a Section 21 notice before 1 May 2026 and didn't issue proceedings by 31 July 2026 — stop. That notice is dead. Take legal advice before doing anything else. The worst thing you can do is serve a notice that has no legal basis and create a paper trail that complicates your actual Section 8 case later.

For ongoing management, build your evidence base now. Ground 8 requires sustained arrears. Ground 7A requires documented ASB. Neither of those cases builds itself — you need rent ledgers, correspondence records, incident logs, and formal written warnings in place before you ever need them in court. Most HMO operators I speak to don't have this infrastructure. They relied on Section 21 as a pressure valve. That valve is gone.

For student HMO operators specifically: identify whether all your occupants qualify as full-time students and whether you intend to re-let to students. If yes, the new student ground may be your most reliable possession route at year-end — but you need to serve the notice correctly and within the right window. Again, qualified legal advice is not optional here.

Finally — and this is the point I keep coming back to — the economics of HMO investment have shifted. Higher turnover risk, longer possession timelines, and more complex compliance requirements all affect yield. If you're evaluating new HMO deals or stress-testing existing ones, the possession exposure is now a first-order variable, not a footnote.

The landlords who will do well in the post-Section 21 world aren't the ones who fight the change. They're the ones who've already rebuilt their operating model around it. Ground 8 with sustained arrears, documented ASB trails, student ground planning — this is the new toolkit. The 31 July 2026 deadline was a one-time cliff edge. Everything from here is the new normal. The question isn't whether the rules changed. It's whether your strategy has.