Diesel Fuel Polishing Services in Ontario
When the power goes out, your backup generator is only as reliable as the fuel in its tank. Diesel that sits for months or years collects water, grows microbes and forms sludge. A failed clear and bright test (C282) is the main reason customers call us.
Contaminated fuel is one of the most common reasons a standby generator will shut down when needed. SAO Contracting provides professional fuel polishing for both underground and above-ground diesel tanks across Ontario, from small generator day tanks to storage tanks where our max capacity is 50,000L. Please note that while we polish both types, we only provide repair services for above-ground tanks.
Our technicians hold TSSA OBT-1 and PM3 certifications and work to CSA B139 and C282 requirements. Your fuel comes back clean, and your system stays compliant. Whether you’re dealing with a failed test or planning ahead, we’ll clean the fuel you already have so you don’t have to replace it.
Request A Quote
Fuel polishing is a scheduled service. Contact us early to book a date that works around your operations.
What Is Diesel Fuel Polishing?
Diesel fuel polishing is a process that cleans the fuel stored in your tank. The fuel is pumped out of the tank and passed through a series of filters and water separators to remove water, sludge, particles and microbial growth. The clean fuel is then returned to the same tank.The key benefit is that you keep your fuel. Instead of draining, disposing of and replacing thousands of litres of diesel, polishing restores it to usable condition.
We polish diesel and red (dyed) diesel stored in both underground and above-ground tanks for generators, fire pumps and bulk storage up to where capacity is 50,000L. Tank repair services are exclusively available for above-ground tanks.
Signs Your Diesel Fuel Needs Polishing
Diesel starts to break down from the day it’s delivered. Condensation, temperature changes and time all add up. Watch for these warning signs:
- Failed clear and bright test (C282):Diesel is contaminated, cloudy, & lost its transparency
- Water in diesel tank: Causes corrosion and feeds microbes in tank reservoirs.
- Milky or cloudy diesel fuel: Indicates suspended water in fuel.
- Diesel bug: Microscopic organisms that deteriorate fuel quality and clog fuel lines.
- Sludge and sediment: Degraded fuel leaves bottom debris.
- Dark or discoloured fuel: Signals degradation or fuel contamination.
- Clogged fuel filters: Frequent replacements indicate contaminated fuel.
- Rust and Metal Particles: Indicates internal tank corrosion caused by trapped water.
- Generator running problems: Hard starts, smoking, or shutdowns.
Early diesel fuel contamination is often invisible. Fuel can look fine at the top of the tank while water and microbes build up at the bottom. A fuel sample and lab analysis is the only reliable way to know the condition of your diesel.
Why Fuel Polishing Matters for Backup Generators
Your backup generator may run for only a few minutes a month during testing, but it has to work the moment the grid fails. If its fuel is contaminated, clogged filters or injector damage can cause it to fail partway through an outage, when hospitals, schools, and care homes can least afford it.
Regular fuel polishing gives you:
Reliability in an Emergency:
Clean fuel means your generator starts and keeps running.
Longer Equipment Life:
Less wear on injectors, pumps and filters, and less internal tank corrosion.
Lower Costs:
Polishing costs far less than disposing of and replacing contaminated fuel or repairing a damaged engine.
Compliance
Helps you meet CSA C282 fuel quality requirements and pass inspections.
Our Fuel Oil Polishing Process: Multi-Stage Diesel Fuel Filtration
Our fuel oil polishing system uses three stages of diesel fuel filtration, each finer than the last, down to 2 microns. For scale, a human hair is about 70 microns wide.
Assessment and Planning:
We review your tank size, access, fuel condition and operating schedule, then book a date that works for your site.
Fuel Sampling:
Fuel testing is only on request. We send samples to a lab for full analysis.
Diesel additive from Fuel Right (ProActive) is applied to break down diesel sludge and restore lubricity to the diesel.
A magnetic filter removes metal particles. A 50-micron bag filter captures large particles and varnished fuel. Two 30-micron fuel/water separators remove free water.
Stage 2 Filtration:
A second magnetic filter, a 25-micron bag filter and two 10-micron fuel/water separators remove finer particles and remaining water.
Stage 3 Filtration:
Two 2-micron fuel/water separators complete the final polish.
The clean fuel goes back into your tank. Post-polishing samples can be sent to the lab so you have documented results.
You receive a summary of the work. Lab reports from before and after polishing are available on request.
Our Equipment: We run two large mobile setups for tanks from less than 2,500L up to where capacity is 50,000L, plus a compact unit for generator day tanks under 2,500L. This lets us match the equipment to the job instead of oversizing or undersizing it.
Industries We Serve
We provide generator fuel polishing and tank fuel polishing for facilities where backup power is critical:
Hospitals and Healthcare Facilities
Emergency power for patient care and life-safety systems.
Schools
Reliable backup power to keep students safe and essential systems running.
Mining Sites
Remote and northern operations where fuel often sits for long periods
Retirement and Long-Term Care Homes
Residents depend on heat, lighting and medical equipment during outages.
Commercial and Industrial Buildings
Office towers, plants and warehouses with standby generators.
Fire Pumps
Diesel-driven fire pumps that must start without fail.
Why Choose SAO Contracting
- Over 12 years of fuel system experience
- Tank polishing capacity is 50,000L
- Advanced 2-micron diesel fuel filtration
- OBT-1 & PM3 certified technicians
- Fully meets CSA C282 requirements
- Generators run safely during service
- Full fuel system service: Beyond polishing, we handle fuel tank installation, and other services including piping, exhaust systems and dampers, so one contractor understands your whole system.
- Your generator stays in service: Polishing doesn’t require shutting down your backup power.
TESTIMONIALS
Recently hired SAO contracting to polish almost 50,000 liters of Diesel Fuel.
SAO always worked safe and efficient and completed the job on time and on budget An absolute pleasure to work with Scott, I would highly recommend them !
We have used SAO Contracting on several power generation projects to address our fuel systems needs. Scott is very knowledgeable, his prices are very good, components are from reputable manufacturers and of high quality and communication is excellent. Highly recommended!
Having used SAO Contracting for my fuel systems needs for a multitude of years, I can certainly speak to the outstanding and exemplary services that Scott and SAO Contracting provides. I always receive prompt attention to my matters and any services delivered are always accompanied by a vast amount of knowledge that is only cultured by extensive years of experience in the trade. I would highly recommend SAO Contracting for your fuel systems needs.
Whenever we needed professional, reliable, and quality work, Scott was someone I knew I could count on. Scott takes pride in doing things properly. His knowledge, attention to detail, and commitment to quality really stood out to me. Just as importantly, Scott was dependable and easy to work with. When you are responsible for buildings and projects, having a contractor you can trust to do the job right is extremely important. I would highly recommend SAO Contracting to anyone looking for knowledgeable, professional, and trustworthy workmanship. You can feel confident that the job will be done right.
Fuel Oil Polishing Across Ontario
SAO Contracting provides diesel fuel polishing services at facilities across Ontario, including:
Northern Ontario +1-705-481-0341
Sudbury, Timmins, Sault Ste. Marie, Thunder Bay
Eastern Ontario +1-613-253-7824
Central & Southern Ontario +1-905-828-4667
Not on the list?
Keep Your Backup Power Ready
Don’t wait for a failed inspection or an outage to find out what’s in your tank. Book your diesel fuel polishing with SAO Contracting today.
FAQs
What does fuel polishing do?
Fuel polishing removes water, sludge, particles and microbial growth from stored diesel by circulating it through a series of filters and water separators. The fuel is returned to your tank clean and usable. This protects your generator and avoids the cost of replacing the fuel.
How much does fuel polishing cost?
Fuel polishing is priced per litre, and the per-litre rate drops as volume goes up. The total depends on tank size, how contaminated the fuel is, and site access. Request a quote with your tank size and location for an accurate price.
Is fuel polishing worth it?
In most cases, yes. Polishing costs much less than draining, disposing of and replacing contaminated fuel. It also costs far less than a generator that fails during a power outage at a hospital, school, or care home.
How long will a fuel tank last?
Properly installed above-ground tanks typically last 20–25 years or longer with routine maintenance. Annual inspections, fuel polishing, and corrosion monitoring significantly extend service life and reduce failure risk.
What regulations apply to fuel tank installations in Ontario?
Installations must comply with CSA B139 and be inspected under TSSA authority. Additional requirements may apply under fire codes and environmental regulations depending on tank size and application. Only OBT-1 technicians can certify fuel systems for delivery approval.
What is a TSSA Fuel Oil Delivery Certificate?
This certificate confirms your fuel system has passed inspection and is legally approved for fuel delivery. It is valid for 10 years. Without it, fuel suppliers cannot refill your tank. SAO Contracting includes certification as part of installation.
Can you install fuel tanks for generators and fleets?
Yes. We install fuel systems for emergency generators, vehicle fleets, construction equipment, and oil-fired heating systems. Each installation is tailored to runtime requirements, load demand, and regulatory standards.
How are fuel tanks protected from leaks?
Modern installations use double-walled tanks, spill containment, overfill prevention, venting, emergency shutoff valves, and optional leak detection sensors. Combined with regular inspections, these measures significantly reduce leak and fire risk.