Section 13 Rent Increase Walkthrough 2026 (Form 4 Step-by-Step)

Section 21 abolished means Section 13 is the only lawful way to raise rent on an assured periodic tenancy in England from 1 May 2026 onwards. Any rent-review clause inside an existing tenancy agreement is unenforceable; any informal "I’m putting the rent up to £1,800 from June" by text is invalid. The increase has to be formal, in writing, on the prescribed Form 4, with at least two months’ notice, no more than once per 12 months, and never in the first 12 months of the tenancy.

The Renters’ Rights Act 2025 also rewired what the First-tier Tribunal can do when a tenant challenges the increase: under the old regime the tribunal could set the rent higher than the landlord proposed; under the new regime the tribunal is capped at the landlord’s proposed figure. This sounds tenant-favourable, but it actually changes the risk calculation for landlords too — the cap removes the upside but also the downside; you cannot lose the increase entirely, only have it reduced toward (or below) the existing rent.

This walkthrough takes you through Section 13 step by step: the rules, the Form 4 content, the date arithmetic, the tribunal route, and the five most common errors that void the notice.

What changed under the Renters’ Rights Act 2025

Section 13 of the Housing Act 1988 was the original statutory rent-increase mechanism for assured tenancies. The Renters’ Rights Act 2025 (in force 1 May 2026) amended Section 13 in three material ways:

The form itself — Form 4 under the Assured Tenancies (Forms) (England) Regulations — was reissued in early 2026 to reflect the new periods. The old Form 4 is invalid for notices served from 1 May 2026 onwards. Always use the current GOV.UK form (linked at the bottom of this guide) rather than a copy stored on your hard drive.

The 12-month gap and the first-12-months freeze

Two date traps catch most landlords:

Gap rule: a Section 13 notice cannot take effect if another Section 13 notice took effect in the previous 12 months. The 12-month clock runs from the effective date (the date the new rent started), not the service date. Worked example: you served Section 13 in September 2025 with an effective date of 1 December 2025. You cannot serve a new Section 13 with an effective date earlier than 1 December 2026. You can serve the notice from 1 October 2026 (two months before the proposed effective date), but the effective date must be on or after 1 December 2026.

First-12-months freeze: from 1 May 2026 onwards, you cannot increase rent at all in the first 12 months of any new tenancy. If a tenant moves in on 1 June 2026, the earliest valid rent increase effective date is 1 June 2027 — served two months earlier on 1 April 2027. This rule is new under the Act and is the most common reason post-RRA Section 13 notices get rejected by tribunals.

Use the Section 13 Rent Increase Calculator to verify both rules against your specific tenancy dates before serving anything.

What goes on Form 4

The prescribed Form 4 has four mandatory blocks:

Block 1 — The parties:

Block 2 — The current rent:

Block 3 — The new rent and effective date:

Block 4 — Tenant’s right of referral:

The full form is published on GOV.UK and must be used as-is — you cannot strip headings, omit blocks, or substitute your own template. A "homebrew" Form 4 is invalid even if it contains all the same information.

Step-by-step: serving a lawful Section 13 notice

Step 1 — Verify eligibility. Confirm the tenancy is an assured periodic tenancy (every new tenancy from 1 May 2026 is, by default). Confirm at least 12 months have passed since the tenancy started and at least 12 months have passed since the last rent increase.

Step 2 — Pick the proposed new rent. The Act does not cap how high you can set the proposed rent, but the tribunal will set the rent at market rate for similar properties in the area if the tenant refers the notice. Pricing more than ~5% above credible market for the area significantly increases the chance the tenant refers — and increases the chance the tribunal sets the rent below your proposed figure. Use a credible local rental data source (Rightmove asking rents, Land Registry / ONS PRS rent index, agent comparable list) to anchor your number.

Step 3 — Pick the effective date. Pick a calendar date at least two months in the future, and confirm it is on or after the rent payment day for that month. Most tenancies use the start-of-month as the rent payment day, so the safe choice is the first of a month at least two clear calendar months ahead.

Step 4 — Download and complete the current Form 4. Always use the live GOV.UK PDF, not a stored copy. Fill in every block in plain English, sign and date.

Step 5 — Serve the notice. Best practice: Royal Mail signed-for to the property address (the tenant’s address by definition), plus a duplicate by hand or email if the tenancy contract permits email service. Save the receipt and proof of delivery for at least two years.

Step 6 — Wait for the effective date. If the tenant does nothing, the new rent applies automatically from the effective date. Do not collect the new rent before the effective date — a premature collection can be argued as estoppel against the increase.

Step 7 — Respond to a tribunal referral if it comes. The tenant has until the day before the effective date to refer the notice to the First-tier Tribunal. If they do, you will be served papers and asked to attend a hearing. The tribunal will set the rent at market rate up to but not exceeding your proposed figure. Bring comparable rent evidence, EPC, condition photos and any improvement bills.

The tribunal route in 2026

A tenant who challenges a Section 13 notice refers it to the First-tier Tribunal (Property Chamber — Residential Property). The tribunal hearing is conducted in writing or in person; the determination is binding on both sides.

What the tribunal looks at:

Outcomes under the new cap:

The tribunal cap means the maximum upside for a landlord is the proposed figure; the maximum downside is the existing rent. This narrows the planning range significantly compared to the old regime, which made it more attractive for tenants to challenge marginal increases (because the tribunal could not set a higher rent than the proposed). In practice we expect referral rates to rise from ~3% (pre-2026) to ~10% (post-2026).

The five errors that most often void a Section 13 notice

1. One-month notice instead of two. Old templates and old advice still cite "at least one month’s notice". Under the RRA 2025 the minimum is two months for any notice served from 1 May 2026 onwards. A 1-month notice served in 2026 is void.

2. First-12-months violation. Trying to increase rent within the first 12 months of a tenancy that started on or after 1 May 2026 is void under the new Act. The earliest valid effective date is exactly 12 months after tenancy start.

3. 12-month gap violation. Two Section 13 notices in 12 months is void; the second notice has no effect and the tenant continues to pay the previous rent.

4. Old form template. A pre-2026 Form 4 (with "at least one month’s notice" language) is invalid for notices served from 1 May 2026. Always use the current GOV.UK PDF.

5. Effective date not on a rent-payment day. If the tenancy is paid monthly, the effective date must be the first day of a rent period, not a mid-month date. A notice with an effective date of 15 May for a tenancy paid on the 1st is void; the tenant continues to pay the previous rent until the next valid notice with a 1-of-the-month effective date.

Use the Section 13 Rent Increase Calculator to verify all five rules in one screen before drafting Form 4. The calculator surfaces the earliest valid effective date, the latest valid service date, and flags both the 12-month gap and the first-12-months freeze.

Worked example: a 2027 rent increase

Tenancy started 1 June 2026, current rent £1,500/month. Landlord wants to increase to £1,650 (10% increase) effective 1 July 2027.

Eligibility checks:

Service plan:

Tenant response window:

If tenant refers:

Next valid increase:

Where to go next

Sources