Key Takeaways
- Fats, oils and grease (FOG) in drains pose serious legal, financial and operational risks for any UK commercial kitchen.
- UK law, including the Water Industry Act 1991, Environmental Protection Act 1990 and Food Safety Act 1990, can result in significant fines and business closures for restaurants causing sewer blockages
- Simple kitchen practices combined with effective grease management systems, including grease traps, grease removal units and regular maintenance, prevent most FOG problems
- Water companies and environmental health officers are increasingly targeting food businesses that contribute to sewer blockages
- Fastfix Drainage & Plumbing offers 24/7 drain unblocking, CCTV surveys and repairs for restaurants across Bristol and the South West with fixed-price quotes. Request a free quote here.
Introduction: Why Fats, Oils and Grease Are a Big Problem for UK Restaurants
Fats, oils and grease enter your drainage system from cooking oils, animal fats from meats, dairy products like butter and cheese, sauces, gravies and food scraps. When this FOG cools in pipes, it solidifies and combines with food waste to form blockages and fatbergs in both private drains and public sewers.
The scale of the problem is significant. Thames Water discovered a 143-tonne fatberg in London’s Whitechapel in 2017, while Exeter dealt with a 10-tonne mass in 2023. Water companies and local authorities are now actively targeting food businesses that contribute to these issues.
This guide provides practical FOG management advice from Fastfix Drainage & Plumbing’s perspective, specifically for restaurants, takeaways, cafes and pubs across Bristol, Somerset, Gloucestershire, Dorset, Wiltshire and South Wales.
How Fats, Oils and Grease Damage Your Drains and Business
FOG enters your drainage system as warm liquid but cools rapidly in pipework. It then congeals, adhering to pipe walls and trapping food particles to form a thick, adhesive layer that progressively restricts flow.
Common symptoms restaurant owners notice include:
- Slow-draining sinks during busy service
- Gurgling sounds from drains
- Bad smells from floor drains
- Repeated blockages during peak periods
Unmanaged FOG can back up into kitchens, causing sewage overflows that contaminate food preparation areas and create immediate food safety concerns. The business impacts include emergency call-outs costing £200 to £500, forced closures losing over £1,000 in daily revenue, and lasting reputation damage from negative reviews.
Repeated blockages can also crack or collapse pipes, leading to excavation and drain repairs costing thousands.
UK Legal Duties Around Fat, Oil and Grease in Restaurant Drains
There is no single “Grease Trap Act” in the UK. Instead, several pieces of legislation work together to enforce good FOG management in commercial kitchens. Breaching these legal requirements can lead to fixed penalties and prosecution, unlimited fines in Crown Court, recovery of clean-up costs, and poor food hygiene ratings.
Landlords, water companies, local councils, environmental health officers, the Environment Agency and building insurers can all become involved when drains fail due to FOG.
Water Industry Act 1991 – Section 111
Section 111 makes it a criminal offence to discharge substances, including fats, oils and grease, that can cause injury, damage or blockages in the public sewer. Water companies across England and Wales actively use this against food businesses with repeated FOG problems.
Consequences typically escalate from formal warnings and action plans to prosecution, with fines reaching £50,000 in Magistrates’ Courts or an unlimited fine in Crown Court. The water company can also recharge costs for clearing fatbergs and jetting sewers back to offending businesses.
Proper grease management equipment, maintenance records and staff training demonstrate compliance during inspections.
Environmental Protection Act 1990 – Duty of Care for Waste
Under the Environmental Protection Act 1990, grease waste and waste cooking oil are classed as controlled waste. Restaurants must use a licensed waste carrier for collection and keep waste transfer notes for at least two years.
Improper storage of grease waste, such as open containers outside, can lead to pest problems, odours and enforcement by your local authority or the Environment Agency. Serious breaches risk substantial fines and potential prison sentences for environmental harm. Check that your contractor’s registration is current and that collection intervals match your waste oil production.
Food Safety Act 1990 and Food Hygiene Regulations
Poor grease management leads directly to dirty, slippery and odorous kitchen environments that attract pests. Environmental health officers can inspect premises under food hygiene regulations and mark down your food hygiene rating when drains and grease traps are not properly maintained.
Outcomes range from hygiene improvement notices to prohibition notices, fines and closure for serious breaches. Showing EHOs evidence of a FOG management plan, service records and training logs supports a higher rating. Good FOG control is due diligence, just as important as temperature monitoring and cleaning schedules for any business that serves hot food.
Best Practice Grease Management in Commercial Kitchens
The most effective strategy combines good kitchen habits, suitable equipment and regular maintenance tailored to your specific site. Start with a survey covering menu type and cooking methods, number of covers per day, equipment generating FOG, and your current plumbing and drainage layout.
BS EN 1825 and Water UK guidance help designers and installers size grease management solutions correctly. Staff behaviour is equally important as equipment, so written procedures should be part of induction and refresher training.
Grease Traps, Grease Removal Units and Dosing Systems
A traditional passive grease trap slows flow through baffles, allowing grease to float and solids to sink while water exits. These retain 90 to 95 per cent of FOG when properly maintained. Automatic grease removal units skim grease into external containers on programmed cycles, reducing manual labour by around 80 per cent. Biological dosing systems inject bacteria and enzymes to break down FOG in pipework but must complement, not replace, physical separation.
| Equipment Type | Install Cost | Best For | Maintenance Level |
|---|---|---|---|
| Passive grease trap | £500-£2,000 | Pot-wash sinks, prep areas | Higher (manual emptying) |
| Grease removal unit | £3,000-£10,000 | Space-limited sites, high volume | Lower (automated) |
| Biological dosing | £200/year | Supplementing traps | Minimal |
The right combination depends on space, budget and maintenance capability. Professional design input is recommended for any business that serves hot food.
Kitchen Practices That Dramatically Cut FOG in Drains
Simple actions prevent FOG entering your drains:
- Dry-wipe plates and pans before washing (captures around 80 per cent of fats)
- Scrape food into bins, never sinks
- Use sink strainers to catch solids
- Never pour cooking oil directly into sinks or floor drains
- Decant oils into labelled containers stored in secure, bunded areas
Clear signage above sinks and checklists near wash-up areas reduce staff errors by up to 60 per cent. These practices slow trap fill-up and lower disposal costs over time.
Maintenance, Cleaning Schedules and Record Keeping
Even the best grease management system fails without planned cleaning. Many UK food businesses clean internal traps every four to six weeks, with more frequent intervals for high-volume fry operations.
Daily or weekly visual checks by kitchen staff help spot high grease levels, odours, slow drainage, and leaks around equipment.
Keep a simple log of inspections, cleaning dates, contractor visits and waste transfer notes. These records prove compliance during water company inspections, EHO visits and insurance claims. Our commercial CCTV drain surveys provide detailed reports with images that satisfy both water company and Environmental Health Officer requirements.
When to Call a Professional Drainage Company
Contact specialists when you experience repeated blockages despite routine cleaning, sewage backing up inside the premises, or unexplained smells from below-ground pipework.
Professional engineers use high-pressure water jetting and CCTV drain surveys to locate and remove hardened FOG deposits. Survey reports with images identify collapsed or misaligned pipes causing grease to build up.
Where FOG has caused structural damage over time, our drain lining service can repair affected pipework without the need for disruptive excavation, restoring full flow capacity quickly.
Fastfix Drainage & Plumbing operates 24/7 across Bristol and the wider South West with fixed-price quotes and no call-out charge for emergency unblocking. Schedule preventive maintenance during quieter trading periods to avoid disruption at Christmas or summer peaks.
Financial Impact: Costs of Ignoring FOG vs Investing in Prevention
Prevention costs a fraction of emergency failures. Consider the comparison:
Prevention costs (annual)
- Grease trap cleaning: £600 to £1,800
- Waste oil collection: £200 to £500
- Periodic drain inspection: £150 to £300
Emergency costs (per incident)
- Emergency call-out: £200 to £500
- Drain jetting: £300 to £600
- Tanker attendance: £500 to £1,000
- Pipe replacement: £2,000 to £10,000 or more
- Forced closure: £1,000 or more per day in lost revenue
Insurers may decline claims if non-compliance with maintenance contributed to the incident. Budget for regular maintenance as a routine operating cost rather than emergency spending. Any restaurant owner who invests in prevention avoids the risk of legal action from their water company or local authority.
How Fastfix Drainage & Plumbing Supports Restaurants with FOG Problems
Fastfix Drainage & Plumbing is a family-run specialist serving restaurants, takeaways, pubs, hotels and catering businesses across Bristol, Somerset, Gloucestershire, Dorset, Wiltshire and South Wales.
Our services for commercial kitchens include:
- 24/7 emergency drain unblocking
- High-pressure water jetting
CCTV drain surveys to identify where grease is building up and provide compliance-ready reports
- Drain repairs and replacement
- General plumbing support
We offer fixed-price quotes with no call-out charges, so you know costs upfront before work begins. Our engineers can recommend practical improvements to ensure free flow through your drainage system and help prevent blockages before they disrupt service.
Call our 24/7 emergency line or request a free fixed-price quote via our website to protect your kitchen from FOG problems.
Frequently Asked Questions about Fat, Oil and Grease in Restaurant Drains
Do UK restaurants have to install grease traps by law?
There is no single UK law requiring grease trap installation by name. However, water companies and local authorities expect effective FOG control. If lack of equipment causes sewer network blockages, you face prosecution under the Water Industry Act 1991. Consult your water company, landlord and a licensed contractor to determine appropriate solutions. New-build or refurbished sites should factor grease management into design under building act requirements to avoid expensive retrofits.
How often should my restaurant’s grease trap be emptied and cleaned?
Most UK commercial kitchens find a four to six week interval works well. The “25 per cent rule” applies: once grease and solids occupy roughly a quarter of the trap’s volume, efficiency drops and cleaning is due. Very busy fry-led operations may need fortnightly service. Monitor levels in your first few months to establish the ideal schedule and dispose of waste through a licensed waste carrier.
What should I do if sewage is backing up into my kitchen during service?
Stop using affected sinks immediately and keep staff and customers away from contaminated areas. Protect food from exposure and call an emergency drainage company rather than using domestic plungers or chemicals. Record the incident with photos, times and affected areas for insurance purposes. After resolution, review your FOG management, staff training and cleaning records to prevent a repeat incident and satisfy any subsequent inspection.
Can chemical drain cleaners solve grease problems in a commercial kitchen?
Over-the-counter chemicals rarely solve persistent FOG issues and can damage pipework or grease removal equipment. Some products interfere with biological dosing systems or void manufacturer warranties. Physical grease removal through jetting and proper separation is the preferred solution. Consult a professional before using any chemical treatments. Chemicals may also create a statutory nuisance through fumes.
How can I prove to inspectors that I am managing FOG responsibly?
Maintain a folder with grease trap service records, invoices, waste transfer notes, staff training records and written FOG procedures. Simple cleaning schedules signed and dated by staff demonstrate due diligence. A recent CCTV survey showing clear drains provides strong evidence of proactive maintenance. Walk inspectors through your controls during visits to support a higher food hygiene rating. This documentation also protects against queries from the Environment Agency regarding waste streams.