Restaurants in Ireland should schedule professional grease trap cleaning every 4–6 weeks. High-volume kitchens may need cleaning every 2–4 weeks, while lower-volume kitchens can stretch to 6–8 weeks, but only if the trap never fills beyond the 25% level.
Anything beyond this risks slow drainage, foul odours, plumbing issues and non-compliance with local regulations.
What is a Grease Trap and Why Do Restaurants Need It?
A grease trap (also called a commercial grease trap or grease interceptor) is a small tank installed within your wastewater line. Its job is simple: separate fats, oils and grease (FOG) from water before it reaches the main sewer.
In a commercial kitchen, food waste, grease, and solids travel into sinks during everyday cleaning. Without a proper grease trap, these materials cool, harden and block your pipes.
Why restaurants need a grease trap:
- Prevents blockages in your drainage system
- Stops slow drains and backflow
- Keeps the kitchen running smoothly
- Controls foul odours coming from pipe build-up
- Ensures compliance with Irish local regulations
- Protects the main sewer from FOG damage
Even the most careful kitchen staff can’t avoid grease-laden wastewater. That’s why a grease trap isn’t just recommended. It’s essential for legal and operational reasons.
Why Does the Cleaning Frequency Matter So Much?
Cleaning frequency directly affects your kitchen’s performance and safety. When grease traps are left too long, fats oils and grease slowly create thick layers, trapping food waste and restricting flow.
Here’s why timing is critical:
1. Preventing drainage issues
FOG thickens fast. Once it reaches the 25% level, water cannot move freely. This leads to:
- slow drainage
- sink backup
- unpleasant gurgling sounds
- wastewater pooling in basins
2. Eliminating foul odours
One of the first signs that your grease trap is overwhelmed is smell. Old FOG + warm kitchens = strong, sour odours that spread quickly.
3. Staying compliant with local regulations
Irish councils require that restaurants maintain their grease trap properly. Failure can result in:
- compliance warnings
- fines
- mandatory re-cleaning
- environmental penalties
4. Reducing emergency callouts
A blocked trap doesn’t wait for a convenient time, it stops service instantly. Emergency plumbing repairs cost much more than regular grease trap maintenance.
5. Extending the lifespan of your drainage system
Regular grease trap cleaning prevents corrosion, pipe damage and unnecessary replacement costs.
Typical Grease Trap Cleaning Frequency for Restaurants
While every restaurant is different, these timelines reflect real patterns seen in Irish commercial kitchens:
Kitchen Type |
Recommended Cleaning Frequency |
Reason / Notes |
| Standard Restaurants (Most Kitchens) | Every 4–6 weeks | Typical FOG output in Irish commercial kitchens. |
| High-Volume Kitchens (takeaways, hotels, busy cafés) | Every 2–4 weeks | Higher levels of grease and solids produced daily. |
| Moderate Kitchens | Every 6 weeks | Moderate FOG generation with regular usage. |
| Low-Volume / Less Oily Cuisine | Every 6–8 weeks | Only acceptable if the trap is regularly inspected. |
| The 25% Rule | Clean when FOG reaches 25% of trap capacity | Most critical guideline; going beyond this level causes slow drainage and functional issues. |
How to Know If You Need More Frequent Cleaning
Even if you follow a schedule, your kitchen’s activity may require quicker cleaning. Watch for these common signs:
1. Slow drainage
If sinks or floor drains take longer to empty, the grease trap is filling.
2. Bad smells
A strong sour, sewage-like or fatty smell near sinks usually means FOG is decomposing.
3. Grease overflowing into pipes
FOG escaping through the outlet is a major red flag.
4. More food waste entering the trap
Busy periods increase waste levels dramatically.
5. Kitchen staff complaining about backup
They’re usually the first to notice small changes.
6. Seasonal spikes
Christmas rush, summer tourism or events increase grease production.
Factors That Determine Your Exact Grease Trap Cleaning Schedule
Your ideal timeline depends on real-world factors inside your kitchen:
- Kitchen Volume: A high-volume kitchen that produces a lot of food, sauces, frying oil or baked goods fills the trap quickly.
- Type of Cuisine: Fried foods, roasts, full breakfasts and high-fat menus generate heavy FOG.
- Trap Size: A small trap needs cleaning more often because it fills faster.
- Staff Habits: If kitchen staff rinse plates without scraping food waste, expect more frequent cleaning.
- Opening Hours: Longer trading hours mean more daily waste.
- Local Regulations: Some councils require additional monitoring.
- Weather & Temperature: FOG hardens faster in cold weather, affecting flow.
What Do Irish Regulations Say About Grease Trap Cleaning?
While exact rules vary by county, most Irish local authorities require:
- proper grease trap installation
- documented regular grease trap maintenance
- cleaning before FOG reaches 25%
- proper disposal of fats, oils and grease
- inspection readiness at any time
Ignoring these rules can lead to:
- fines
- enforcement letters
- temporary closure
- required emergency cleaning
- penalties for environmental contamination
Signs Your Grease Trap Is Overdue for Professional Cleaning
If you notice any of these, your trap needs immediate attention:
- Foul odours around sinks
- Wastewater rising back through drains
- Slow drains across multiple sinks
- Visible grease floating on top of the trap
- Noise or bubbling sounds in pipes
- Kitchen staff reporting repeated blockages
- Interior floors bare ecoming wetter than usual
These are early warning signals that grease and solids have built up significantly.
Professional Cleaning vs In-House Cleaning: What’s the Difference?
Here is a simple comparison so you understand why professional cleaning is required.
In-House Cleaning (Kitchen Staff) |
Professional Grease Trap Cleaning Service |
| Only cleans surface grease | Removes all grease and solids fully |
| Staff lack specialised equipment | Uses suction, jetting & professional tools |
| No disposal capability | Waste is disposed legally & environmentally |
| Temporary relief only | Long-term drainage improvement |
| Risk of non-compliance | Meets local regulations |
| Can damage trap parts | Performs safe, full-system cleaning |
In-house cleaning is not a replacement for professional maintenance, it only helps between scheduled services.
How to Reduce Grease Trap Buildup Between Professional Visits
Small habits make a big difference:
- Train kitchen staff to scrape plates before washing
- Avoid flushing hot oil down sinks
- Use drain strainers
- Wipe pans with paper before washing
- Dispose of food waste properly
- Avoid chemicals that break down grease (they reform further down the pipe)
- Schedule regular grease trap maintenance without skipping appointments
These steps help maintain your grease trap and reduce emergencies.
Which is the Best Grease Trap Cleaning Service in Ireland?
If you’re looking for experienced professionals who understand commercial kitchens and handle grease traps daily, we at Drain Away provide Professional Grease Trap Cleaning Services in Ireland.
We serve counties including Offaly, Dublin, Galway, Kildare, Laois, Limerick, Westmeath, and Kilkenny, offering reliable, compliant and expert grease trap cleaning for restaurant owners across Ireland. Contact us today.
Key Takeaways
- Most restaurants need cleaning every 4–6 weeks.
- High-volume kitchens need cleaning every 2–4 weeks.
- Use the 25% FOG rule as your main guide.
- Slow drains, smells, and backups mean your trap is full.
- Regular cleaning prevents fines, blockages and downtime.
- Professional cleaning is essential; DIY is not enough.
FAQs
1. How long does a professional grease trap cleaning take?
Usually 45–90 minutes, depending on size and buildup.
2. Can a grease trap be cleaned too often?
No, frequent cleaning does not harm the trap.
3. Does weather affect grease trap performance?
Yes. Cold weather solidifies FOG faster.
4. Do I need documentation for inspections?
Yes. Logs help prove regular maintenance.
5. What size grease trap is ideal for a busy restaurant?
It depends on kitchen volume, but larger traps reduce cleaning frequency.
