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How Canadian GST, HST and PST apply to mold remediation invoices
GST HST PST mold remediation invoices depend on your CRA business number, the place of supply rules and provincial rates. Here is how to bill each job correctly.
What to take away
- GST HST PST mold remediation invoices are driven by three things: your CRA business number, the place of supply rules, and the province where the work happens.
- You must register for GST/HST once you exceed the small supplier threshold, and you charge tax from the date you register, not from the date you get around to it.
- Quebec adds QST on top of GST, so a Quebec invoice shows two tax lines and two registration numbers.
- BC PST applies to parts, materials and some services, but not to most labour on real property. Saskatchewan PST works differently again.
- Drying, disposal, equipment and travel each need their own wording so the customer and the CRA can both see what was taxed and why.
- Keep every invoice, receipt and tax remittance record for at least six years.
Registering a CRA business number before you invoice remediation work
Every remediation operator in Canada starts here. The CRA business number is a nine-digit account identifier. You add program accounts to it: RT for GST/HST, RP for payroll, RC for corporate income tax.
You can register before you make a dollar. Most new operators should, because a general contractor or insurer will ask for the number before they release a purchase order. A missing business number stalls payment.
Registration is free and done through CRA My Business Account or by phone. You get the number immediately in most cases. The RT account is the one that appears on your invoices.
When registration becomes mandatory
You must register once your taxable supplies exceed the small supplier threshold over four consecutive calendar quarters. Below that, registration is optional.
Optional registration still makes sense for most remediation firms. You reclaim GST/HST you paid on drying equipment, vehicles, consumables and subcontractors. Without registration, that tax is a permanent cost.
Once you register, you charge tax on every taxable supply from that point forward. You cannot pick and choose jobs.
What to do before your first invoice
Work through this in order:
- Get the CRA business number and the RT account.
- Decide whether you file annually, quarterly or monthly.
- Set up a separate bank account for tax collected.
- Build an invoice template with fields for tax type, rate and registration number.
- Confirm the place of supply for each job before you send anything.
The tax you collect is not your money. It sits in your account until you remit it. Operators who spend it get caught at year end. A simple routine helps: see our mold remediation services packages for the account structure that keeps tax funds separate from operating cash.
GST/HST rates by province and how to pick the right one
The GST/HST rate depends on where the supply is made, not where your office sits. That is the core of the place of supply rules.
Here is the rate table you should keep taped inside your estimating binder.
| Province or territory | Tax applied | Rate |
|---|---|---|
| Alberta | GST | 5% |
| British Columbia | GST + PST | 5% + 7% |
| Manitoba | GST + RST | 5% + 7% |
| New Brunswick | HST | 15% |
| Newfoundland and Labrador | HST | 15% |
| Northwest Territories | GST | 5% |
| Nova Scotia | HST | 14% |
| Nunavut | GST | 5% |
| Ontario | HST | 13% |
| Prince Edward Island | HST | 15% |
| Quebec | GST + QST | 5% + 9.975% |
| Saskatchewan | GST + PST | 5% + 6% |
| Yukon | GST | 5% |
Rates change. Nova Scotia has moved more than once in the last two decades. Check the current rate before you send a large invoice, and never assume last year's number still holds.
Reading the rate off the job address
A mould job in Ontario is HST at 13%. The same scope in Alberta is GST at 5%. Your invoice must reflect the tax that applies where the work is performed.
If you bill a property manager in Toronto for a building in Winnipeg, you charge Manitoba tax, not Ontario tax. The customer's address is not the deciding factor.
Mixed supplies on one invoice
A single invoice can carry more than one treatment. Remediation labour, a disposal charge and a piece of equipment rental may not all fall under the same rule in a PST province.
Split the invoice into labelled lines. Put the tax type beside each line. A lump sum invites a reassessment.
Quebec QST and the GST/QST registration stack
Quebec does not use HST. It runs GST and Quebec QST side by side, and you register for both through Revenu Québec.
If you are based outside Quebec but perform work there, you generally need to register for QST once you exceed the province's threshold. The Quebec government publishes the current registration and filing obligations on its finance and tax portal.
A Quebec invoice shows two tax lines and two registration numbers. GST and QST are calculated separately, and QST is applied to the price before GST, not on top of it.
What the invoice must show
Your Quebec invoices need the GST registration number, the QST registration number, the rate for each, and the amount of each. Customers claim both as input tax credits, so a missing number means a phone call.
Many Quebec customers, including large property managers and insurers, will reject an invoice that combines the two into one line. Keep them separate.
Working for a Quebec customer from Ontario
An Ontario remediation firm drying a basement in Gatineau charges GST and QST because the work happens in Quebec. The Ontario HST registration does not cover it.
Register for QST before you take the job. Retroactive registration is possible but messy, and it delays payment.
BC PST and Saskatchewan PST treatment of drying and remediation services
British Columbia and Saskatchewan both run a provincial sales tax alongside GST, but they treat services differently.
BC PST on remediation work
In BC, PST generally applies to goods, software and some services. Labour on real property improvement is usually exempt from PST. Remediation of a building is treated as work on real property.
The catch is materials. If you supply and install drywall, insulation or lumber, PST may apply to the materials portion. If you buy those materials with a valid PST exemption for resale or installation, you do not pay PST on the purchase.
Equipment rental is its own question. Short-term rentals of tangible goods can attract PST. Check the current rules on the province's taxes and tax credits page before you bill a rental line.
Saskatchewan PST on the same job
Saskatchewan PST applies to tangible personal property and to a defined list of services. Remediation and drying labour is not on that list in the ordinary case, so most labour is PST exempt.
Materials you supply and install are a different matter. Saskatchewan treats contractors as the final consumer of materials they install, which means you pay PST when you buy, and you do not charge it separately on the invoice.
That is the opposite of the BC treatment in some cases. If you operate in both provinces, keep the two sets of rules separate in your template.
Why this matters for your margin
If you absorb PST on materials in Saskatchewan and forgot to price it in, you lose it. Build the tax into your material markup. Our pricing and profit guide walks through how to load tax costs into the estimate without pricing yourself out of the job.
Invoice wording examples for labour, equipment, disposal and travel
Wording is where audits are won and lost. Each line should say what was done, where, and what tax applies.
Labour
Use a line like this on an Ontario job:
Remediation labour, 14 hours, containment setup, HEPA vacuuming and antimicrobial application at 42 Elm Street. HST 13% applied.
On an Alberta job, the same line ends with "GST 5% applied." The wording does not change, only the tax.
Equipment
Equipment lines need a duration and a rate basis:
Negative air machine rental, 6 days at daily rate, delivered and set up on site. GST 5% applied.
If you rent out equipment to another contractor rather than use it on your own job, that is a separate supply and may attract PST in BC. Label it as a rental, not as part of the remediation scope.
Disposal
Debris removal and disposal, 2.4 tonnes of contaminated building material, transported to licensed landfill. Disposal fee included. GST 5% applied.
Disposal is generally part of the remediation service on real property. Keep the landfill receipt in the job file.
Travel
Travel and mobilization, 180 km round trip, crew of three, two vehicles. GST 5% applied.
If you bill travel as a separate disbursement rather than as part of the service, the tax treatment can shift. Most remediation firms bill it as part of the service to keep it simple.
A worked example
A Halifax firm remediates a flooded basement after a storm. The job runs four days.
Show the numbers
| Remediation labour, 96 hours | $9,600 |
|---|---|
| Negative air machines, 4 units, 4 days | $1,280 |
| Debris disposal, 3.1 tonnes | $930 |
| Travel, 240 km | $340 |
| Subtotal | $12,150 |
| HST | $1,701 |
| Total | $13,851 |
The invoice shows the HST registration number, the 14% rate, and the total. Nothing is bundled into a single mystery line. You can build this format once and reuse it. A quote template with pricing examples shows how the same line structure carries from estimate to invoice.
Place of supply rules when a crew crosses a provincial border
Crews cross borders constantly. A Manitoba firm dries a cottage in northwestern Ontario. An Alberta crew works in southeastern BC. The tax follows the work.
The general rule
For services related to real property, the place of supply is where the property sits. That is the rule that governs remediation, drying and restoration.
It does not matter where the contract was signed, where the customer's head office is, or where your truck is registered. The building's address sets the tax.
When you need to register in another province
If you make taxable supplies in a province where you are not registered, you may need to register there. The threshold rules differ between GST/HST provinces and the PST provinces.
For BC PST, registration depends on whether you make taxable sales in the province and whether you meet the small seller threshold. For Quebec QST, the threshold is separate from the federal one.
Track the value of work you do in each province. If border work is occasional, you may stay under the threshold. If it becomes routine, register.
Practical steps before the crew leaves
- Confirm the property address and the province.
- Check whether you are registered in that province.
- Confirm the tax type and rate for that province.
- Update the invoice template before the job closes.
- File the registration paperwork if the threshold is close.
Getting this wrong is expensive. You can end up remitting tax you never collected, out of your own margin. Before you take cross-border work, confirm your registration obligations alongside the other requirements in our guide to licenses does a mold remediation business need.
Filing, remitting and record retention for remediation businesses
Filing is the part new operators underestimate. The money is not yours, and the deadline does not move.
Filing frequency
Your reporting period depends on your revenue. Small operations usually file annually or quarterly. Larger firms file monthly.
You can file online through CRA My Business Account, by NETFILE, or by phone for simple returns. The CRA sets out each option, along with the filing and remitting rules for GST/HST, in its GST/HST for businesses hub.
Most remediation firms with employees and subcontractors should file quarterly. Monthly filing means more paperwork but tighter cash control.
What you remit
The amount you remit is the tax you collected minus the input tax credits you claimed on purchases. Drying equipment, vehicles, fuel, consumables and subcontractor invoices all generate credits.
Keep the receipts. A credit you cannot document is a credit you lose.
Record retention
Keep records for at least six years from the end of the tax year they relate to. That includes invoices you issued, invoices you received, bank statements, and proof of remittance.
For remediation work, add the job file: moisture readings, scope notes, photos, landfill receipts and equipment logs. These support the invoice if the CRA asks why a job was billed the way it was.
Common filing mistakes
- Charging the wrong provincial rate.
- Missing a QST registration number on a Quebec invoice.
- Claiming input tax credits without a valid supplier invoice.
- Failing to register after crossing the small supplier threshold.
- Mixing tax funds with operating cash.
Each of these is fixable before it happens. None is fixable cheaply after. Our how to start mold remediation business guide covers the registration sequence in the order a new operator should tackle it.
Common questions
Do I charge GST/HST on a remediation job if the customer is a homeowner? Yes. Residential customers pay the same tax as commercial ones. The rate depends on the province where the home sits.
What if my revenue is under the small supplier threshold? You can stay unregistered, but you cannot claim input tax credits on your purchases. For equipment-heavy remediation work, voluntary registration usually pays for itself.
Does BC PST apply to my drying labour? Labour on real property improvement is generally PST exempt in BC. Materials and short-term equipment rentals are the lines to check.
Do I need a separate registration number for Quebec? Yes. You register for GST and QST with Revenu Québec, and both numbers appear on the invoice.
How long do I keep remediation job files? At least six years from the end of the tax year. Keep moisture readings, photos and disposal receipts alongside the invoice.
Can I put one tax line on an invoice covering two provinces? No. Split the invoice by property address so each line carries the correct provincial tax.
