Letting to a family member (UK buy-to-let landlords)

Letting to a family member can feel straightforward, but it brings many of the same responsibilities as renting to anyone else—plus extra considerations around mortgages, tenancy law and lender risk. If you get the details wrong, the consequences can be costly.

This guide explains the main points landlords typically need to consider when renting to a family member.

Is renting to a family member legal?

Yes. In the UK, it is generally legal to rent to a family member.

However, the legality of the arrangement is only one part of the picture. If you have a residential mortgage, your mortgage contract may restrict you from letting the property out. In many cases, you may need to switch to a buy-to-let mortgage before you can rent the property.

Why lenders treat it as higher risk

Some lenders view family lets as higher risk because rent collection can be more informal and landlords may be less likely to act quickly if payments are late. That can affect how lenders assess affordability and risk.

As a result, you may find that:

• some buy-to-let products may not allow letting to family members
• lenders may apply stricter checks than they would for a standard tenant

Do you need a tenancy agreement?

Yes. Even if the tenant is a family member, you should use a proper tenancy agreement.

A tenancy agreement should:

• set out the rent, term and responsibilities clearly
• reflect the rights and obligations that apply to tenants under UK landlord law
• be consistent with the type of tenancy you are granting

Landlord compliance still applies

Letting to a family member does not remove your duties as a landlord. You will still need to ensure your property meets relevant requirements, including (where applicable) energy efficiency and fire safety obligations.

Do you need a rental deposit?

You are not always required to take a deposit in every situation, but taking one can provide practical protection.

A deposit can act as security for issues such as damage beyond normal wear and tear or unpaid rent—helping you avoid disputes later.

If you do take a deposit, you should follow the deposit protection rules that apply to the tenancy type and timing.

Deposit protection: key principles

In practice, deposit protection usually involves:

• placing the deposit into a government-approved scheme
• giving the tenant the required prescribed information
• following the correct process if you later return the deposit

Can a deposit be used for all damage?

No. Deposit deductions are typically limited to what the law allows.

Commonly, you cannot deduct for wear and tear. Deductions usually need to be supported by evidence and fall within the scope of what the rules permit.

Can you charge a discounted rent?

You can offer a discount in principle, but it may create problems with mortgage affordability.

For buy-to-let lending, lenders often assess whether the rental income is sufficient to cover mortgage costs. If the rent is reduced, it may be harder to meet the lender’s rental income requirements.

In addition, lenders may expect rent to be market-related rather than heavily discounted, especially where the tenant is a family member.

Do you still pay tax on rental income?

Yes. Rental income is generally taxable.

In most cases, you calculate tax based on rental income minus allowable expenses. Typical expenses can include certain costs related to letting and maintaining the property.

Tax rules for landlords can be detailed, and what you can claim may depend on your circumstances. Many landlords use an accountant to ensure their records and claims are correct.

Mortgages and letting to family members

Residential mortgage restrictions

If you currently have a residential mortgage, it may restrict letting the property out. Some mortgages allow limited arrangements (for example, certain forms of occupancy), but renting the property to a family member as a tenant is often not permitted.

Switching to buy-to-let

If your intention is to let the property, you will typically need to switch from a residential mortgage to a buy-to-let mortgage.

Even then, you may find that:

• not all buy-to-let lenders accept family lets
• the lender may require additional information or impose specific conditions

Equity and deposit considerations

Buy-to-let lending commonly requires you to have sufficient equity in the property and/or additional funds to contribute towards the mortgage deposit.

Early repayment charges (ERCs)

If you are moving from a residential mortgage to buy-to-let (or remortgaging within buy-to-let), you may face early repayment charges depending on your existing mortgage terms.

What to consider before you proceed

Letting to a family member can work well, but it helps to be prepared for the practical and financial realities:

• confirm your current mortgage allows letting (and whether it requires a switch)
• check whether the buy-to-let product you’re considering allows family lets
• plan for lender affordability calculations based on the rent you intend to charge
• ensure you have a proper tenancy agreement and meet landlord compliance duties
• consider whether a deposit is appropriate and, if so, protect it correctly
• keep clear records for tax purposes

Using a specialist mortgage broker

Because family lets can be restricted by mortgage terms and assessed differently by lenders, it’s often beneficial to discuss your plan with a specialist mortgage broker.

A broker can help you understand which buy-to-let options may be available for your circumstances and what information lenders typically expect when the tenant is a family member.