Date Published 14 August 2026
This is one of the questions Poole landlords ask us most often:
'How much am I legally allowed to increase the rent by?'
The short answer is that there is no fixed percentage cap on rent increases in England.
There isn't a rule saying that a landlord can only increase the rent by 5%, 10% or the rate of inflation.
However, that doesn't mean a landlord can simply choose any figure they like.
Since the main Renters' Rights Act changes came into force on 1 May 2026, rent increases have become more structured. Landlords must now follow the statutory Section 13 process, use the correct form, provide sufficient notice and ensure that the proposed rent does not exceed the open-market value of the property.
So, while there may not be a percentage cap, there is a market-rent limit and a very definite legal process.
What changed on 1 May 2026?
Private assured tenancies in England are now periodic rather than being granted for a fixed term.
That means landlords can no longer wait until the end of a six or twelve-month fixed term and offer a 'renewal' at a higher rent.
Existing rent-review clauses also cannot be used for new rent increases after 1 May 2026.
Instead, a landlord who wants to increase the rent must use Section 13 of the Housing Act 1988 and serve the tenant with the new Form 4A.
This applies even if the landlord and tenant have already discussed the increase and agreed the amount.
Is there a maximum rent increase?
There is no fixed legal percentage.
The maximum is effectively the open-market rent—the amount the property could reasonably be expected to achieve if it were being offered to a new tenant on the same terms.
For example, imagine a tenant is currently paying £950 per month, but genuinely comparable properties are letting for approximately £1,100.
There isn't a rule restricting the landlord to a £25 or £50 increase. The landlord could propose a larger adjustment towards the market rent, provided the evidence supports it and the correct procedure is followed.
However, if similar homes are letting for around £1,000, increasing the rent to £1,200 simply because the landlord's mortgage has become more expensive would be difficult to justify.
The market value is based on the property—not the landlord's personal costs.
What determines the market rent in Poole?
Online listings can be useful, but landlords need to compare like with like.
A three-bedroom house in Upton isn't automatically comparable with every other three-bedroom house advertised in the BH16 postcode.
The market rent can be affected by:
The precise location.
The type and size of the property.
The number and size of the bedrooms.
Its condition and presentation.
Whether it has parking.
The size and usability of the garden.
Energy efficiency.
Whether it is furnished or unfurnished.
Local transport and school access.
The property's overall standard.
The terms on which it is being let.
Rental values can vary considerably between Upton, Hamworthy, Creekmoor, Canford Heath and other parts of Poole.
Even two houses on the same road may not have the same rental value if one has off-road parking, a modern kitchen and a good-sized garden while the other requires updating.
A sensible rent review should use genuinely comparable evidence, not simply the most expensive property a landlord can find online.
How often can a landlord increase the rent?
A landlord cannot increase the rent during the first year of a new tenancy.
The first increase cannot take effect until at least 52 weeks have passed since the tenancy began.
After that, the rent can normally only be increased once every 52 weeks.
This rule applies even if the last increase happened under an old rent-review clause before the new legislation took effect.
Landlords should therefore keep an accurate record of:
The tenancy start date.
The date of the last rent increase.
The previous rent.
The current rent.
How the last increase was implemented.
When the next increase could legally take effect.
Serving a notice early doesn't allow the new rent to begin early. The proposed start date must still comply with the annual restriction.
How much notice must the tenant receive?
Landlords must give at least two months' notice using Form 4A.
The notice should clearly state:
The tenant's name.
The rental property address.
The landlord's details.
The agent's details, where applicable.
The current rent.
The proposed rent.
The date the new rent will begin.
The increase must start at the beginning of a tenancy period.
For example, if a monthly tenancy period starts on the 20th, the new rent would usually also need to begin on the 20th.
Selecting an arbitrary date in the middle of that period could make the notice invalid.
Landlords should also retain evidence showing when and how the notice was served. The notice may be delivered personally, sent by post or emailed where the tenancy agreement permits service by email.
Can the rent still be increased by mutual agreement?
It is always sensible to discuss a proposed rent increase with the tenant first.
A straightforward conversation can explain why the review is taking place and give the tenant an opportunity to raise any concerns.
However, an informal agreement does not replace the statutory process.
The Government's current landlord guidance says Form 4A and the Section 13 procedure must be used every time the rent is increased—even where the tenant has already agreed to the new amount.
Therefore, the safest process is:
Review the current market evidence.
Discuss the proposed increase with the tenant.
Complete the correct Form 4A.
Give at least two months' notice.
Ensure the start date complies with the annual restriction.
Keep evidence that the notice was served.
If a landlord serves Form 4A and subsequently agrees to reduce or delay the proposed increase, that further agreement should be recorded clearly in writing.
Can the tenant challenge the increase?
Yes.
If the tenant believes the proposed rent is above the open-market value, they can apply to the First-tier Tribunal for a rent determination.
Their application must be received before the date on which the proposed new rent is due to begin.
The tribunal will consider what rent the property could reasonably achieve on the open market under the same tenancy terms.
It may look at:
Comparable local rental properties.
The condition of the home.
Its size and facilities.
The tenancy terms.
Relevant local market evidence.
The tenant cannot be required to pay more than the amount originally proposed by the landlord, even if the tribunal believes the market rent is higher.
This is another reason landlords should avoid serving speculative increases in the hope that the tenant won't question them.
A well-researched increase supported by genuine local evidence is much easier to explain and defend.
Should landlords always increase to the maximum market rent?
Not necessarily.
The legally available rent and the best commercial decision are not always the same thing.
A reliable tenant who pays on time, looks after the property and wants to remain for several years has considerable value.
Increasing the rent too aggressively could cause that tenant to leave. The landlord may then face:
An empty period without rent.
Reletting and referencing costs.
Cleaning or decoration.
Maintenance between tenancies.
The uncertainty of selecting a new tenant.
Additional time and administration.
Suppose a landlord could potentially achieve an extra £50 per month by reletting.
That is £600 over a year.
If the existing tenant leaves and the property sits empty for just one month, much of that additional income could disappear immediately.
That doesn't mean landlords should leave rents untouched forever. Allowing the rent to fall substantially below the market can lead to a much larger and more difficult adjustment later.
Smaller, properly researched reviews at sensible intervals are often easier for everybody than leaving the rent unchanged for six years and suddenly trying to increase it by several hundred pounds.
What if the property is currently well below market rent?
This is where the absence of a percentage cap becomes important.
A landlord may legally propose an increase to the open-market level, even if that represents a significant percentage change from the existing rent.
However, the landlord should consider both the evidence and the likely effect on the tenant.
In some cases, a landlord may decide to increase the rent in stages rather than moving to the full market figure immediately.
Any later increase would still need to wait until the next permitted annual date and follow the Form 4A process again.
The landlord cannot agree today that the rent will automatically rise every six months until it reaches the desired amount.
Common rent-increase mistakes
The most common problems are usually procedural rather than deliberate.
These can include:
Using an old version of the form.
Trying to rely on a rent-review clause.
Increasing the rent less than 52 weeks after the previous increase.
Giving less than two months' notice.
Selecting the wrong start date.
Failing to include every joint tenant.
Entering the wrong property address.
Serving the notice incorrectly.
Relying solely on an informal agreement.
Proposing a figure that cannot be supported by market evidence.
Failing to keep proof that the notice was served.
A landlord may have a perfectly reasonable case for increasing the rent, but that doesn't rescue an invalid notice.
If the procedure is wrong, the landlord may need to begin again.
What should Poole landlords do before increasing rent?
Before proposing an increase, we recommend that landlords:
Confirm the tenancy start date.
Check the date of the last rent increase.
Review the rent currently being paid.
Gather recent evidence from genuinely comparable local properties.
Take account of the property's condition and facilities.
Decide on a fair and supportable market rent.
Discuss the proposal with the tenant.
Use the current Form 4A.
Give at least two months' notice.
Keep proof that the notice was served.
Update all accounting and management records once the new rent begins.
The aim shouldn't be to pick the highest possible figure.
It should be to arrive at a fair market rent that protects the landlord's investment while giving a good tenant a reason to stay.
Local knowledge matters
Automated online valuations can provide a rough guide, but they don't always understand the difference between one end of a road and the other—or why two apparently similar properties achieve very different rents.
At Lewis Dean, we look at the property itself, its condition, the tenancy history and genuine local evidence before recommending a rent.
If you own a rental property in Poole, Upton, Hamworthy, Creekmoor or Canford Heath and you are wondering whether the current rent is still reasonable, please speak to us before serving notice.
We can give you a straightforward view of the likely market rent and help ensure the increase is handled properly.
No unrealistic promises and no picking a figure out of thin air—just sensible local advice based on what comparable properties are actually achieving.
