Will the CRA or Revenu Québec Find Me If I Don’t Register for Sales Tax?

Many new businesses, freelancers, and online sellers believe they can stay “under the radar” by avoiding GST/QST registration especially if they operate part-time, work from home, or have irregular income. But both the CRA and Revenu Québec actively monitor unregistered businesses, and they have multiple ways to detect when someone should be registered but isn’t.

This guide explains how tax authorities identify unregistered businesses, what happens when you’re caught, and why voluntary registration is always safer.

How Tax Authorities Detect Unregistered Businesses

1. Bank Deposit Analysis

CRA and RQ regularly compare:
• bank deposits
• reported income
• T4A slips
• payments from platforms

If deposits look like business revenue, they investigate.

2. Cross-Matching with T4A, T5018, and RL Slips

If a client issues you:
• a T4A,
• RL-1,
• RL-31, or
• subcontractor slip (T5018),

tax agencies see that you are earning business income even if you haven’t registered.

3. E-Commerce and Payment Platforms

Platforms share data, such as:
• PayPal
• Stripe
• Etsy
• Shopify
• Amazon
• Uber
• DoorDash

These platforms provide transaction totals that tax authorities compare with GST/QST registrations.

4. Digital Footprint Monitoring

Revenu Québec actively scans:
• business websites
• online ads
• social media pages
• Google Maps listings
• Instagram business profiles

If you advertise taxable services, they expect registration.

5. Client Complaints or Auditor Cross-Checks

During an audit of one business, auditors often identify:
• suppliers
• subcontractors
• consultants
• service providers

If you invoiced a taxable service without GST/QST, you may be flagged.

6. Business Number Activity Without GST/QST Registration

If you register for:
• payroll
• incorporation
• import/export numbers
• municipal permits

but not GST/QST, the system alerts Revenu Québec.

7. Cross-Province Data Sharing

CRA and RQ exchange:
• GST data
• income tax data
• sales tax anomalies
• platform reporting information

If CRA detects taxable activity, RQ eventually knows too.

8. Random Compliance Sweeps

Both agencies conduct outreach campaigns targeting:
• freelancers
• contractors
• small retailers
• home-based businesses
• industries with chronic under-registration

If you fall into one of these groups, you may be contacted.

What Happens If They Find You?

1. Forced Registration

Revenu Québec can register you themselves retroactively.

2. Retroactive GST/QST Assessments

If you exceeded $30,000 at any point:
• tax authorities calculate all GST/QST you should have collected
• you must pay it out of pocket
• clients are not required to repay retroactive tax

3. Interest

Daily interest applies from the date the tax should have been remitted.

4. Penalties

Penalties may apply for:
• failure to register
• failure to collect
• failure to remit
• late filing
• negligence (in serious cases)

5. Denial of Input Credits

Until you’re registered:
• ITCs (GST credits)
• ITRs (QST credits)

cannot be claimed.

6. Audit Exposure

Being caught unregistered increases your audit risk for:
• income tax
• GST/QST
• payroll
• past years

7. Collection Action

If you ignore assessments, tax authorities may:
• freeze bank accounts
• seize refunds
• garnish income
• register liens

Common Myths About Avoiding Registration

 “I’m small, they won’t notice.”

They will — especially if you accept electronic payments.

 “I only sell online, so I’m invisible.”

Platforms report your transactions.

“I didn’t hit $30,000 in revenue.”

If you came close, they calculate rolling quarters — not calendar years.

“I can register later without trouble.”

Late registration creates retroactive tax liability.

 “I only have one client.”

A single T4A can trigger an investigation.

When You SHOULD Register Before Being Found

You should register immediately if:
• you are earning taxable income
• you are close to hitting $30,000
• you already passed the threshold
• you advertise publicly
• you receive platform-based payments
• clients ask for your tax numbers
• you want to claim input credits

Voluntary registration avoids penalties and preserves credibility.

Mackisen Strategy

Mackisen CPA helps businesses:
• determine whether they must register
• complete GST/QST registration properly
• monitor the $30,000 threshold
• fix late registration
• calculate retroactive tax exposure
• use voluntary disclosure when required
• build compliant invoicing and tax systems

We ensure you stay ahead of CRA and Revenu Québec instead of reacting to them.

Real Client Experience

A freelance marketer received a letter asking why she wasn’t registered. Mackisen calculated her rolling revenue, registered her immediately, and avoided penalties.

A Shopify seller was contacted by Revenu Québec after Facebook ads triggered a scan. Mackisen cleaned up records and ensured full compliance.

A contractor paid tax out of pocket when forced to register retroactively. Mackisen used voluntary disclosure to reduce interest and penalties.

Common Questions

Will CRA or RQ always find out?
Almost always especially with digital payments.

Can I wait until next year?
Not recommended. Liability grows every month.

What if I already crossed $30,000?
Register immediately and speak to a CPA.

Is cash business safer?
No cash deposits in your bank still show up.

Why Mackisen

With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps businesses stay compliant with GST/QST rules, avoid penalties, and repair issues before CRA or Revenu Québec intervenes.