Data Cleaning for Charities: A Complete Guide to Supporter & Donor Data

A charity's supporter database is one of its most valuable fundraising assets.

It can also become one of its biggest data-quality problems.

People move house. Email addresses stop working. Mobile numbers are disconnected. Supporters change their communication preferences. Duplicate records appear. People ask not to be contacted again. And, sadly, long-standing supporter databases will inevitably contain records for people who have died.

If those changes are not reflected in your CRM, fundraising activity becomes less effective and potentially more intrusive.

Letters are sent to the wrong addresses. Emails bounce. Fundraisers call dead numbers. Supporters receive duplicate appeals. People who have opted out are contacted again. And money is spent communicating with records that are no longer usable.

Charity data cleaning is the process of identifying and dealing with those problems before they affect your fundraising.

For charities that want to improve the quality of their supporter data, Data Soap provides data cleaning and validation services designed for charity and fundraising databases, including email, mobile, landline and address validation alongside TPS, CTPS and MPS screening.

This guide explains what charities should consider cleaning, which checks apply to different fundraising channels, how data cleaning relates to UK GDPR and PECR, and where specialist suppression services such as the Fundraising Preference Service fit into the process.

What is charity data cleaning?

Charity data cleaning is the process of reviewing, validating, standardising and suppressing information held about supporters, donors and prospects.

A typical supporter CRM might contain:

• names

• postal addresses

• email addresses

• mobile numbers

• landline numbers

• donation history

• communication preferences

• fundraising consent records

• event participation

• Gift Aid information

• volunteer information

• suppression records

Cleaning does not mean simply deleting anything that looks old.

The aim is to understand the status and quality of each record so the charity can make appropriate decisions about how it should be used.

For example, an incorrectly formatted address might be corrected. An invalid email might be flagged. A dead mobile might be suppressed from an SMS campaign. A TPS-registered number might be excluded from an unsolicited telephone fundraising campaign. A supporter who has asked not to hear from the charity again should be recorded appropriately so that preference is respected in future.

Good data cleaning is therefore a mixture of validation, correction, suppression and preference management.

Does GDPR apply to charities?

Yes.

UK GDPR applies to charities when they process personal data, just as it applies to commercial organisations, public bodies and other organisations.

The Fundraising Regulator's current guidance is explicit that every organisation, regardless of size, must comply with UK GDPR when it processes personal data. For charitable fundraising, relevant legislation can include UK GDPR, the Data Protection Act 2018 and the Privacy and Electronic Communications Regulations 2003 (PECR).

That means charity status does not provide a general exemption from data-protection law.

Personal data can include obvious information such as:

• a supporter's name

• home address

• email address

• telephone number

• donation records

• communication preferences

It can also include information that identifies a person indirectly.

Depending on the work a charity carries out, it may also hold special category data relating to matters such as health, religion, racial or ethnic origin or sexual orientation. UK GDPR gives these categories additional protection, and charities processing them may need both an Article 6 lawful basis and a separate Article 9 condition.

So the answer to "does GDPR apply to charities?" is straightforward:

Yes. If a charity processes personal data, UK GDPR applies, alongside any other relevant legislation and fundraising rules.

Does GDPR require charities to clean their data?

UK GDPR does not prescribe a particular commercial "data cleaning service" or tell organisations to clean their CRM every three or six months.

What it does contain is an accuracy principle.

The ICO says organisations should take reasonable steps to ensure personal information is not incorrect or misleading and should keep it updated where that is necessary for the purpose for which it is being used. If information is found to be inaccurate, reasonable steps should be taken to correct or erase it.

Whether information needs updating depends on what you are using it for.

For a historic record of a donation, an old address could remain accurate as a record of where the donor lived when the donation was made.

But if you intend to use that same address to send a fundraising appeal today, whether it remains current becomes much more important.

That distinction is useful when thinking about charity data cleaning.

The purpose is not to continually rewrite historical information. It is to make sure data being relied upon for current activities is sufficiently accurate for those activities.

Why charity databases become inaccurate

Supporter databases are rarely static.

Even if the information was perfect when it entered the CRM, its accuracy can deteriorate over time.

A supporter might:

• move house

• change their email provider

• abandon an old email address

• change mobile number

• disconnect a landline

• change their name

• change their marketing preferences

• request that fundraising communications stop

• create multiple records through different donation channels

• die

The charity itself can introduce errors too.

Manual entry can create typing mistakes. Different fundraising platforms can format addresses differently. Event registration systems can create duplicate contacts. Imported spreadsheets may use inconsistent field structures. Third-party integrations can introduce incomplete records.

The longer a supporter database has existed, the more likely it is that these different issues have accumulated.

Why clean data matters for fundraising

Poor-quality data costs charities money.

A printed fundraising pack sent to an unusable address still incurs print, fulfilment and postage costs.

An email sent to an invalid inbox consumes sending capacity and contributes nothing to a campaign.

A fundraiser repeatedly calling disconnected numbers spends time that could have been used speaking to supporters.

There is also a less measurable but potentially more important cost: supporter trust.

Sending multiple copies of the same appeal to one household, contacting someone who has repeatedly opted out, or continuing to send communications addressed to someone known to have died can damage the relationship between a charity and its supporters.

The current Code of Fundraising Practice expects charities to have appropriate systems and procedures for respecting fundraising preferences and keeping relevant data accurate and up to date.

Clean data therefore supports both fundraising efficiency and respectful supporter management.

What data should charities clean?

There is no single "charity data clean".

Different parts of the supporter record require different checks.

1. Validate supporter email addresses

Email remains one of the most important fundraising and supporter-engagement channels.

But email databases accumulate problems.

Addresses can contain:

• spelling mistakes

• invalid domains

• missing characters

• dead mailboxes

• disposable addresses

• formatting errors

Sending large campaigns to invalid addresses can also affect deliverability and sender reputation.

Email validation can identify addresses that appear invalid or undeliverable before a fundraising campaign is sent.

Data Soap's email validation service can be used for bulk database cleaning or real-time validation when a supporter first submits an email address.

For charities, this can be particularly useful before:

• major fundraising appeals

• event campaigns

• regular-giving communications

• newsletters

• supporter reactivation campaigns

Validation does not establish whether you have permission to send marketing to an email address. It answers a data-quality question rather than a marketing-permission question.

That distinction matters.

2. Check whether supporter mobile numbers are still active

Mobile numbers often remain inside fundraising CRMs long after they stop being useful.

A correctly formatted mobile number does not necessarily mean the number is still active.

For older supporter databases, charities can use an HLR lookup to obtain current mobile-network information without calling or texting the supporter.

This can help identify numbers that may no longer be useful before they are included in telephone or SMS activity.

HLR validation is especially relevant when preparing:

• telephone fundraising campaigns

• SMS appeals

• event reminders

• supporter-service campaigns

• older donor files

Again, HLR validation only addresses the technical status of the mobile.

It does not provide consent, establish someone's identity or give permission to contact them.

3. Validate landline numbers

Landlines remain relevant for many charities, particularly those with long-standing or older supporter bases.

A fundraising CRM may contain landline numbers that were added many years ago.

Over time, some will have been disconnected or entered incorrectly.

Data Soap's enhanced landline validation can help charities distinguish stronger records from landlines that appear dead or unreliable before those numbers are sent to a fundraising team.

For telephone fundraising operations, combining number validation with preference screening can prevent agents wasting time on records that either cannot connect or should not be called.

4. Validate and standardise postal addresses

Direct mail remains an important fundraising channel.

But it is also an expensive channel in which poor data creates a very visible cost.

Incorrect postcodes, incomplete addresses and inconsistent formatting can create avoidable problems before a mailing even reaches the print stage.

PAF stands for Postcode Address File. It is Royal Mail's database of UK postal delivery addresses.

Using PAF address validation can help standardise addresses, fill address elements and check records against recognised UK delivery addresses.

Royal Mail describes PAF-based cleansing as the process of verifying, correcting and standardising address records against its address data.

It is important not to confuse PAF validation with gone-away or deceased suppression.

PAF validates the address itself.

It does not tell you whether a particular donor still lives there or whether they have died.

Those questions require different data sources.

5. Screen postal fundraising against MPS where appropriate

Address validity is only one part of preparing a direct-mail campaign.

Charities also need to consider postal marketing preferences.

The Mailing Preference Service, or MPS, allows people to indicate that they do not want unsolicited personally addressed direct mail.

The current fundraising framework specifically identifies MPS as one of the preference sources charities may need to consider when they do not have specific permission to contact somebody.

Data Soap provides an MPS checking service that can be used to identify matching postal suppression records before a fundraising mailing is produced.

That can help charities avoid printing and posting fundraising communications to people who have indicated that they do not want them.

6. Screen telephone fundraising against TPS and CTPS

Telephone fundraising has its own preference registers.

The Telephone Preference Service covers individual subscribers, including consumers, sole traders and certain partnerships.

The Corporate Telephone Preference Service covers corporate subscribers such as limited companies and LLPs.

For many charity supporter databases, TPS will be the more obvious register. But fundraising activity involving businesses, corporate partnerships or mixed contact lists may also require CTPS consideration.

Data Soap can screen telephone numbers against TPS, CTPS and internal Do Not Call data before records are passed to a calling campaign.

If you need more detail, see our guides to how the Telephone Preference Service works and the difference between TPS and CTPS.

A clean telephone number does not automatically mean it is appropriate to call.

Number validity and marketing preference are separate checks.

7. Maintain your charity's own suppression list

External preference registers are not the only source of opt-outs.

A supporter can tell your charity directly that they no longer want fundraising communications.

For example:

"Please stop calling me."

"Please don't send me fundraising letters."

"Unsubscribe me from your emails."

Those preferences need to flow back into the charity's CRM and campaign systems.

Simply deleting a contact can sometimes create another problem: the same supporter may later be re-imported from another system because there is no suppression record indicating that they previously objected.

Good preference management therefore often involves retaining enough information to ensure that the objection continues to be respected.

Your internal suppression data should be treated as part of the data-cleaning process, not as a completely separate activity.

8. What about the Fundraising Preference Service?

Charities also need to understand the Fundraising Preference Service, or FPS.

The FPS is operated by the Fundraising Regulator and allows people to ask named charities to stop sending them direct marketing communications.

For charities registered in England, Wales and Northern Ireland, FPS requests can cover addressed mail, email, text messages and telephone calls.

This is different from TPS, MPS and general data validation.

An FPS request concerns that person's relationship with a specific charity.

When a charity receives an FPS notification, it needs to access the request through the Fundraising Preference Service and update its own records appropriately. The Fundraising Regulator says people can follow up if marketing continues after 21 days, with further failures potentially becoming Code of Fundraising Practice issues.

Data Soap does not provide Fundraising Preference Service screening.

Charities should therefore manage FPS notifications through the Fundraising Regulator's FPS process and ensure those requests are reflected in their own CRM or suppression records.

This distinction is worth making clear:

Data Soap can help with MPS, TPS, CTPS and your own telephone suppression processes, but FPS requests need to be managed separately by the charity.

9. Identify deceased supporters

Deceased suppression deserves special consideration for charities.

Continuing to send fundraising communications addressed to somebody known to have died can cause significant distress to relatives and can damage trust in the charity.

The current fundraising framework specifically expects charities to stop sending fundraising communications to people they know have died.

Specialist deceased-suppression datasets can help organisations identify these records.

Data Soap does not currently provide a deceased-suppression service, so charities requiring this should use an appropriate specialist source and then ensure the resulting suppression is reflected in their supporter CRM.

Do not treat address validation as a substitute for deceased suppression.

They solve completely different problems.

10. Identify gone-away supporters

Another common problem is a donor who has moved while the old address remains in the CRM.

PAF can establish whether an address itself is valid.

It cannot establish that Jane Smith still lives at that address.

Specialist gone-away or change-of-address data is needed where a charity wants to determine whether a named supporter has moved.

As with deceased data, that should form a separate part of the broader database-cleaning strategy where it is relevant.

11. Find duplicate supporter records

Duplicates can appear when the same person enters a fundraising database through different routes.

A supporter might:

• donate online

• register for an event

• make a telephone donation

• sign up for a newsletter

• become a volunteer

• make another donation using a different email address

If those systems do not correctly identify the existing supporter, several CRM records can be created.

Duplicates can cause:

• multiple copies of the same appeal

• conflicting communication preferences

• inaccurate supporter counts

• fragmented donation histories

• difficulty understanding lifetime value

• unnecessary postage

• confusing supporter experiences

Deduplication therefore belongs in a complete data-quality programme.

The difficult part is deciding what counts as the same person.

Two people can share a surname and address. One supporter can have several emails. Household members can share a telephone number.

For that reason, sophisticated deduplication should use appropriate matching rules rather than simply deleting records that look similar.

Data cleaning and charity marketing preferences

One of the biggest mistakes in fundraising data management is treating technical validation and permission as the same thing.

They are not.

An email can be perfectly valid while belonging to somebody who has unsubscribed.

A mobile can be live while the subscriber is registered with TPS.

A postal address can be perfectly formatted while the person has asked not to receive fundraising mail.

A useful way to think about the different checks is:

Question	Appropriate process
Is this email technically deliverable?	Email validation
Does this mobile appear active?	HLR/mobile validation
Does this UK landline appear live?	Landline validation
Is this a recognised postal address?	PAF validation
Has this person opted out of unsolicited postal marketing through MPS?	MPS screening
Is this telephone number registered with TPS/CTPS?	TPS/CTPS screening
Has this person asked our charity not to contact them?	Internal suppression/preferences
Has the person used FPS to stop fundraising communications from us?	Charity manages the FPS request
Has this supporter died?	Specialist deceased suppression
Has this supporter moved?	Specialist gone-away/change-of-address data

A genuinely clean supporter database needs to understand both data quality and communication preference.

What changed for charity email and text marketing in 2026?

There has been a significant change to charity fundraising marketing.

On 5 February 2026, a new charitable purposes soft opt-in came into force.

This can allow qualifying charities to send certain electronic direct marketing without obtaining prior consent, but only where all of the requirements are met.

The ICO says the charity must have obtained the person's contact details directly, through the person expressing an interest in or offering/providing support for the charity's purposes. The marketing must solely further the charity's charitable purposes, and the person must have been given a clear opportunity to opt out both when their details were collected and in every subsequent communication.

There is another crucial limitation.

The charitable purposes soft opt-in can only be used for contact details obtained on or after 5 February 2026.

It cannot simply be applied retrospectively to an old supporter database collected before the new rule came into force.

For charities, this makes accurate CRM fields particularly important.

Your database may now need to distinguish between:

• supporters who have explicitly consented

• supporters who qualify for the charitable purposes soft opt-in

• supporters contacted under another appropriate basis

• people who have opted out

• historic records where the soft opt-in does not apply

The ICO recommends keeping clear records showing which method applies to each person.

Data quality is therefore about more than having a working email address.

The charity also needs reliable information about why that address is being used.

Does the new charity soft opt-in mean you can email everyone?

No.

It is not permission to email an entire historical donor database.

The requirements still need to be met.

For example, the charitable purposes soft opt-in does not apply simply because a charity happens to possess an email address.

The charity must have obtained the details directly from the person in the required circumstances and must have provided the required opt-out opportunities.

The ICO also specifically says there is no such thing as a third-party marketing list that is "soft opt-in compliant".

So charities should be cautious about treating the 2026 change as a blanket expansion of every existing fundraising list.

What about bought or third-party charity data?

Third-party data introduces additional considerations.

A clean record is not necessarily a usable marketing record.

For electronic marketing, the ICO says that if a bought-in list is being used, people on that list must have provided valid consent covering the organisation and the relevant communication method where consent is required. The charitable purposes soft opt-in cannot be transferred to a charity via a third-party list.

For telephone and postal activity, charities also need to consider relevant preference registers, direct objections and the lawful basis for processing personal information.

Before using third-party fundraising data, ask:

• Where did the data come from?

• When was it collected?

• How was it collected?

• What was the person told?

• What communication permissions exist?

• When were preference registers last checked?

• Are opt-outs being supplied?

• How current are the contact details?

Data validation can improve the technical quality of a third-party list.

It cannot repair an inadequate lawful basis or create marketing permission that did not exist in the first place.

Charity data cleaning and Gift Aid

Gift Aid is another reason accurate supporter records matter, but it should not be confused with a general contact-data clean.

Charities have separate requirements around Gift Aid declarations and the information they retain to support claims.

Accurate names and addresses can make supporter administration easier and reduce inconsistencies between systems.

However, validating an address through PAF does not establish whether a donation qualifies for Gift Aid or whether a declaration is valid.

Those are separate questions.

Think of address validation as improving the quality and consistency of the underlying supporter record rather than as a Gift Aid eligibility check.

When should a charity clean its database?

There is no universal legal rule saying every charity must perform a complete database clean every three months, six months or once a year.

The appropriate frequency depends on the data and how it is used.

A better approach is to clean data at meaningful points in its lifecycle.

When data first enters the charity

Validation at the point of capture can prevent obvious errors from entering the CRM.

Examples include:

• validating an email entered on a donation form

• checking and standardising a postal address

• validating a telephone number

• recording communication preferences accurately

Preventing poor data is usually easier than fixing it later.

Before a major fundraising campaign

A large postal, telephone, email or SMS campaign creates an obvious point at which data quality matters.

Before launch, check the relevant fields and suppression sources for that channel.

When importing data

CRM migrations, event-platform imports and third-party files can introduce large numbers of records at once.

Validation before or during import can prevent a poor-quality dataset from contaminating the main supporter database.

After repeated failures

Repeated email bounces, returned mail or failed telephone contacts should feed back into the CRM.

A database should learn from campaign results rather than repeatedly attempting the same failed contact.

As an ongoing process

Larger charities may benefit from validation being built directly into forms, APIs, CRM workflows and campaign preparation.

This moves data cleaning away from occasional emergency projects and towards continuous data-quality management.

A practical charity data-cleaning workflow

A complete supporter-data clean might follow this sequence.

Step 1: Understand what is in the database

Identify the fields, systems and sources involved.

Look at where supporter records originated and how current they are.

Step 2: Deduplicate carefully

Identify likely duplicate supporter records before spending money validating and communicating with them.

Retain preference and donation information when records are merged.

Step 3: Standardise addresses

Use PAF validation to correct and standardise UK address data where appropriate.

Step 4: Validate email addresses

Identify invalid, incorrectly formatted or undeliverable email records.

Step 5: Validate telephone numbers

Use HLR for relevant mobile-number validation and appropriate landline validation for UK fixed-line numbers.

Step 6: Apply external preference registers

Depending on the campaign, consider MPS for postal fundraising and TPS/CTPS for telephone activity.

Step 7: Apply internal preferences

Check your CRM for direct opt-outs, unsubscribe records and Do Not Call instructions.

Step 8: Apply FPS requests

Maintain the suppression information provided to your charity through the Fundraising Preference Service.

This is managed through the charity's FPS process rather than through Data Soap.

Step 9: Apply specialist deceased and gone-away suppression

Where appropriate, use specialist data sources for these checks.

Step 10: Preserve the results

Do not just export a "clean file", run a campaign and forget about it.

Feed useful results back into the CRM.

Record information such as:

• what was checked

• the result

• when it was checked

• where the result came from

• relevant communication preferences

• appropriate suppression status

That creates a much more useful long-term data-quality process.

What can Data Soap clean for a charity?

Data Soap brings several of the contact-data checks charities commonly need into one platform.

Depending on the campaign, a charity can use Data Soap to help with:

Data	Data Soap check
Mobile numbers	HLR/mobile validation
UK landlines	Enhanced landline validation
Email addresses	Email validation
UK postal addresses	PAF address validation
Telephone marketing preferences	TPS & CTPS screening
Internal telephone suppressions	DNC management
Postal marketing preferences	MPS screening

You can use these checks for individual records, bulk files or, depending on the validation type, integrate them into your systems through an API.

For an overview specifically designed around fundraising databases, see our data cleaning services for charities and fundraising organisations.

There are also important areas that Data Soap does not currently provide as dedicated screening services, including:

• Fundraising Preference Service requests

• deceased suppression

• gone-away suppression

We think it is better to be clear about those distinctions than to describe every form of charity data hygiene as the same service.

Charity data cleaning is about supporter trust, not just clean spreadsheets

The benefit of cleaner supporter data is easy to measure in wasted postage, bouncing emails and unproductive calls.

But that is only part of the value.

Fundraising depends on relationships.

A supporter who has donated to a charity for ten years should not receive three copies of the same appeal because their CRM records were duplicated.

A bereaved family should not repeatedly receive fundraising mail addressed to a deceased relative after the charity knows that person has died.

Someone who has asked to stop receiving fundraising messages should not be reintroduced into campaigns because one system failed to update another.

Good supporter-data management reduces those risks.

It helps charities communicate with people using information that is more accurate, more current and more reflective of their actual preferences.

That makes data cleaning part of supporter care as much as database administration.

Charity data cleaning FAQs

Does GDPR apply to charities?

Yes. UK GDPR applies to charities that process personal data. Charities must also consider the Data Protection Act 2018, PECR where relevant, and applicable fundraising standards. Charity status does not create a general exemption from data-protection law.

What is charity data cleansing?

Charity data cleansing is the process of improving supporter and donor records by validating, correcting, standardising, deduplicating and suppressing data where appropriate.

It can include email validation, phone validation, address checking and marketing-preference screening.

How often should a charity clean its database?

There is no single frequency suitable for every charity.

Clean data when its accuracy matters: at collection, before major campaigns, during CRM migrations and when records show signs of becoming outdated.

High-volume fundraising organisations may benefit from continuous validation.

Does a charity need consent to contact supporters?

It depends on the channel, the circumstances and the lawful basis or PECR rule being relied upon.

For electronic marketing to individuals, consent is normally required unless an applicable exception such as the charitable purposes soft opt-in applies.

For other channels, different rules can apply.

What is the charitable purposes soft opt-in?

It is a PECR provision that came into force on 5 February 2026 and can allow qualifying charities to send certain electronic marketing that furthers their charitable purposes without prior consent where all requirements are met.

Among other requirements, the charity must obtain the contact details directly from the person on or after 5 February 2026 in connection with their interest in or support for the charity's purposes, and offer an opt-out at collection and in every subsequent message.

Can charities use the soft opt-in on an old donor database?

Not simply because those people previously donated.

The charitable purposes soft opt-in only applies where the relevant requirements are met and the contact details were obtained on or after 5 February 2026.

Historic supporters may still be contactable where another valid basis or permission applies, but the new soft opt-in cannot just be retrospectively applied to the whole database.

What is the Fundraising Preference Service?

The Fundraising Preference Service allows people to ask named charities to stop sending them direct fundraising marketing through selected channels.

Relevant charities receive FPS requests and must update their own suppression records accordingly. Data Soap does not provide FPS screening.

Do charities need to check TPS?

Charities making relevant live marketing calls need to consider TPS and, where corporate subscribers are involved, CTPS.

TPS screening does not replace internal opt-outs or other requirements relating to telephone fundraising.

Do charities need to check MPS?

MPS should form part of the consideration around personally addressed fundraising mail where the charity does not have specific permission to contact the person. The current Code of Fundraising Practice identifies MPS, TPS and FPS as relevant preference sources when appropriate.

Does PAF tell a charity if a supporter has moved?

No.

PAF validates postal addresses. It does not establish that a particular individual still lives at an address.

Specialist gone-away or change-of-address data is required for that purpose.

Does PAF identify deceased supporters?

No.

Deceased suppression requires specialist data and should not be confused with postal-address validation.

Can data cleaning make a charity GDPR compliant?

No single data-cleaning process makes an organisation "GDPR compliant".

Data cleaning can support obligations such as the UK GDPR accuracy principle, but compliance also involves matters such as lawful basis, transparency, security, retention, individual rights and appropriate governance.

Can charities clean data before every fundraising campaign?

Yes, and campaign preparation is a particularly useful point at which to validate the fields and preferences relevant to that campaign.

An email appeal may require a different set of checks from a postal appeal or telephone campaign.

Improve the quality of your charity's supporter data

Fundraising databases inevitably change.

The question is whether those changes are detected before inaccurate or inappropriate records reach the next campaign.

Data Soap's charity and fundraising data cleaning services can help you validate mobile numbers, landlines, emails and UK postal addresses while checking relevant telephone and postal preference registers.

That allows fundraising teams to spend less time and money on contact data that cannot be used effectively and gives CRM teams better information to work with.

Clean supporter data is not just about having a tidier database.

It is about communicating with the right people, using the right details, through the right channels, while respecting the choices supporters have made.