Grease Trap Cleaning FAQs

A grease trap is a plumbing device designed to intercept fats, oils and grease (commonly known as FOG) before they enter the drainage system. It works by slowing down the flow of wastewater from kitchen sinks, floor traps and food preparation areas, allowing grease to float to the surface while heavier food particles settle at the bottom. The relatively cleaner water then flows into the sewer system.

Grease traps play an important role in preventing grease from accumulating inside drainage pipelines, where it can harden over time and cause recurring blockages, unpleasant odours and overflowing drains. They are commonly installed in restaurants, cafés, food courts, hotels, commercial kitchens and food manufacturing facilities.

Like any piece of equipment, grease traps require regular cleaning and maintenance. If grease and sludge are allowed to build up beyond the grease trap's capacity, its effectiveness is significantly reduced, increasing the risk of drainage problems.

Regular grease trap cleaning is essential for maintaining an efficient drainage system and reducing the risk of costly plumbing problems. As grease, fats, oils and food waste accumulate inside the trap, its ability to separate grease from wastewater gradually decreases.

Without regular cleaning, excessive grease can escape into the drainage system where it hardens inside pipes, contributing to recurring blockages and expensive emergency repairs. An overloaded grease trap may also produce unpleasant odours, attract pests and create hygiene concerns within food preparation areas.

For commercial kitchens, routine grease trap maintenance helps support smooth operations by reducing the likelihood of unexpected drainage disruptions. It also allows the grease trap to continue performing its intended function effectively.

The appropriate grease trap cleaning frequency depends on the amount of fats, oils and grease (FOG) generated by your food preparation activities. While every food establishment is different, PUB recommends that grease traps be cleaned at least once every two weeks by an NEA Licensed General Waste Collector (Class C). Establishments with higher grease loading, such as restaurants with heavy frying or high-volume cooking, may require more frequent cleaning.

Cleaning frequency should not be based solely on a fixed schedule. Factors such as the type of cuisine, customer volume, operating hours, menu changes and the amount of grease discharged into the drainage system all influence how quickly a grease trap fills. If oil and grease accumulate faster than the maintenance interval, the cleaning frequency should be increased to maintain effective grease separation and comply with discharge requirements.

Regular grease trap cleaning helps:

• Prevent grease from entering the private sewerage system.
• Reduce the risk of drain blockages and grease trap overflows.
• Minimise foul odours and hygiene issues.
• Improve the performance and lifespan of the grease trap.
• Support compliance with PUB's recommended maintenance practices.

Businesses should also remember that grease trap cleaning is only one part of an effective maintenance programme. PUB recommends periodic cleaning of the private sewerage system, routine inspections and, where necessary, oil and grease sampling to ensure the discharged trade effluent complies with regulatory requirements.

If a grease trap is not cleaned regularly, grease and food waste will continue to accumulate until the trap can no longer separate grease effectively. Once this happens, grease begins to enter the drainage system, where it can harden inside pipes and contribute to recurring blockages.

Neglected grease traps may also result in:

• Slow-draining sinks and floor traps.
• Overflowing grease traps.
• Foul odours in kitchen areas.
• Increased pest activity.
• Reduced drainage efficiency.
• More frequent emergency plumbing call-outs.
• Shorter service life of the grease trap.

For commercial kitchens, ignoring grease trap maintenance can also disrupt daily operations, particularly during peak business hours when drainage demand is highest.

For food establishments in Singapore, grease trap cleaning should be carried out by an NEA Licensed General Waste Collector (Class C), as greasy waste must be collected, transported and disposed of in accordance with the applicable regulatory requirements. PUB also recommends engaging licensed contractors to clean grease traps following its recommended cleaning procedures.

Professional grease trap cleaning involves more than simply removing the layer of grease from the surface. A proper service includes the complete removal of accumulated fats, oils, grease, sludge and food waste, followed by cleaning the grease trap to restore its effective operating capacity. The collected greasy waste must then be transported and disposed of through the appropriate licensed channels.

Attempting to clean a commercial grease trap without the appropriate equipment and licensed waste collection arrangements may result in incomplete cleaning, improper disposal of greasy waste and recurring drainage problems. Regular servicing by a licensed contractor helps maintain the grease trap's performance and supports compliance with Singapore's regulatory requirements.

Yes. A grease trap can reach or exceed its effective capacity even when your kitchen sinks and floor traps continue to drain normally. This is because grease traps are designed to separate fats, oils and grease (FOG) from wastewater—not to indicate when maintenance is due through visible drainage problems.

As grease accumulates, the trap has less capacity to separate new grease from wastewater. Eventually, grease begins to pass through the trap and enter the drainage system, where it can solidify inside pipes and contribute to recurring blockages, unpleasant odours and reduced drainage performance.

Waiting until drainage problems appear often means the grease trap has already been operating inefficiently for some time. Regular preventive cleaning helps maintain its performance and reduces the likelihood of grease entering the sewerage system.

A foul-smelling grease trap is usually caused by the decomposition of accumulated grease, food particles and organic waste inside the trap. As these materials remain in the grease trap, they begin to break down, producing gases that create unpleasant odours.

Common causes include:

• Overdue grease trap cleaning.
• Excessive grease accumulation.
• Large amounts of food waste entering the trap.
• Inadequate cleaning of settled sludge.
• Poor housekeeping practices within the kitchen.

While occasional odours may occur during normal operation, persistent or unusually strong smells often indicate that the grease trap requires immediate maintenance.

Regular cleaning removes accumulated waste before it decomposes, helping to improve hygiene and reduce unpleasant odours within the kitchen.

A grease trap may overflow when it can no longer effectively separate and retain grease, fats, oils and food waste. This usually occurs because the trap has exceeded its holding capacity or because wastewater is unable to flow through the system efficiently.

Common causes include:

• Grease trap overdue for cleaning.
• Excessive grease accumulation.
• Heavy sludge build-up.
• Blocked inlet or outlet pipes.
• Blocked downstream drainage pipelines.
• Grease trap undersized for the kitchen's current operations.

An overflowing grease trap should be addressed promptly, as it may affect kitchen operations, create hygiene concerns and increase the likelihood of grease entering the drainage system.

Simply emptying the visible grease may not resolve the underlying issue if sludge remains at the bottom of the trap or if downstream drainage pipes are partially blocked.

Yes. A poorly maintained grease trap is one of the most common contributors to blocked kitchen drainage systems.

When the grease trap reaches capacity, grease is no longer effectively separated from wastewater. Instead, fats, oils and grease pass into the connected drainage pipelines where they cool, harden and gradually adhere to the inside of the pipes.

Over time, this build-up narrows the pipe's internal diameter and traps food particles and other debris, increasing the likelihood of recurring blockages.

Regular grease trap cleaning significantly reduces the amount of grease entering the drainage system. However, if grease has already accumulated within the pipes, additional services such as high-pressure water jetting may be required to restore the drainage system's full flow capacity.

Professional grease trap cleaning should include the removal, transportation and proper disposal of the collected greasy waste in accordance with Singapore's regulatory requirements.

During the cleaning process, accumulated grease, sludge and food waste are removed from the grease trap using suitable equipment. The waste should then be transported and disposed of by an NEA Licensed General Waste Collector (Class C), ensuring it is handled responsibly and in compliance with the applicable requirements.

When engaging a grease trap cleaning contractor, it is advisable to confirm that waste disposal forms part of the service and that the collected waste is managed through the appropriate licensed channels.

Cleaning the grease trap restores its ability to separate grease from wastewater, but it does not remove grease that has already accumulated inside the connected drainage pipelines.

Over time, grease, fats and food residue can build up along the internal walls of the drainage system. Even after the grease trap has been cleaned, these deposits remain and may continue to restrict water flow, leading to recurring blockages.

In many cases, grease trap cleaning should be complemented by high-pressure water jetting to remove accumulated grease within the drainage pipes. If the problem persists, a CCTV drain inspection may be recommended to identify structural issues such as displaced joints or root intrusion.

A grease trap should be cleaned before it becomes overloaded. Waiting until it overflows or causes a blockage can result in unnecessary disruption to your business.

Common signs include:

• Strong or persistent foul odours.
• Slow-draining sinks or floor traps.
• Grease trap overflowing.
• Grease visible inside inspection chambers.
• Frequent drain blockages.
• Increased pest activity around the grease trap.
• Grease escaping into downstream drains.

In some cases, there may be no obvious warning signs, which is why following a planned maintenance schedule is generally more effective than waiting for symptoms to appear.

Yes. Regular grease trap cleaning is one of the most effective ways to reduce unpleasant odours associated with commercial kitchen drainage systems.

As grease, food waste and organic sludge accumulate, they begin to decompose and produce gases that create unpleasant smells. Removing these materials during routine maintenance helps eliminate the source of the odour rather than simply masking it.

If unpleasant smells continue after the grease trap has been cleaned, the cause may lie elsewhere within the drainage system. Grease build-up inside connected pipes, blocked floor traps or stagnant wastewater may require further investigation and maintenance.

Yes. Routine grease trap maintenance significantly reduces the risk of emergency drainage issues by preventing excessive grease from entering the drainage system.

When grease is intercepted and removed before it accumulates inside the pipes, the likelihood of blockages, overflows and emergency call-outs is greatly reduced. Preventive maintenance also allows potential issues to be identified early, before they disrupt kitchen operations.

For many restaurants, cafés and commercial kitchens, scheduled grease trap cleaning forms an important part of an overall preventive maintenance programme that may also include high-pressure water jetting and periodic CCTV drain inspections.

• Regular grease trap cleaning.
• High-pressure water jetting of connected drainage lines.
• Periodic CCTV drain inspections where recurring issues are experienced.
• Oil & Grease (Non-Hydrocarbon) sampling where required.

Together, these services help maintain efficient drainage, reduce emergency disruptions and support long-term system performance.

A professional grease trap cleaning service involves more than simply removing the layer of grease floating on the surface. The objective is to restore the grease trap's full operating capacity by removing all accumulated waste and ensuring it functions as designed.

A comprehensive grease trap cleaning service typically includes:

• Removal of accumulated fats, oils and grease (FOG).
• Removal of settled sludge and food waste.
• Cleaning of the internal surfaces of the grease trap.
• Inspection of the inlet and outlet for visible obstructions.
• Proper collection and disposal of greasy waste by an NEA Licensed General Waste Collector (Class C).
• Recommendations for future maintenance if any issues are observed.

Depending on the condition of the drainage system, additional services such as high-pressure water jetting or CCTV drain inspection may be recommended if grease has already accumulated in the downstream pipelines.

A grease trap may fill up faster than expected for several reasons, many of which are related to changes in kitchen operations rather than the grease trap itself.

Common reasons include:

• Increased customer volume.
• A menu with more fried or oily food.
• Poor kitchen practices allowing excessive grease and food waste into sinks.
• An undersized grease trap.
• Extended operating hours.
• Delayed maintenance or missed cleaning schedules.

If the grease trap begins filling more quickly than before, it may indicate that the existing maintenance schedule should be reviewed or that the grease trap capacity is no longer adequate for the business.

Yes. An inadequately maintained grease trap can contribute to pest activity by providing a food source for insects and rodents.

As grease, food particles and organic waste accumulate, they begin to decompose, creating conditions that may attract pests if maintenance is neglected. Overflowing grease traps and food residues around access covers can further increase the likelihood of pest activity.

Regular grease trap cleaning, good housekeeping practices and proper waste management help reduce these risks and support a cleaner kitchen environment.

If a grease trap continues to overflow shortly after cleaning, the problem may extend beyond the grease trap itself.

Possible causes include:

• A blocked downstream drainage pipeline.
• Heavy grease accumulation within connected pipes.
• An undersized grease trap.
• Damaged or obstructed inlet or outlet pipework.
• Structural defects within the drainage system.
• Excessive wastewater flow beyond the grease trap's design capacity.

In these situations, cleaning the grease trap alone may temporarily improve conditions without resolving the underlying issue. Additional investigations, such as high-pressure water jetting or CCTV drain inspection, may be required to identify the root cause.

Choosing the right contractor involves more than comparing prices. A reliable contractor should provide a complete service that includes thorough cleaning, proper waste disposal and practical maintenance advice.

When evaluating a contractor, consider whether they:

• Arrange for greasy waste to be collected and disposed of by an NEA Licensed General Waste Collector (Class C).
• Follow PUB's recommended grease trap cleaning procedures.
• Remove both grease and settled sludge during servicing.
• Can identify drainage issues beyond the grease trap itself.
• Offer complementary services such as high-pressure water jetting and CCTV drain inspection when required.
• Provide clear service reports or maintenance recommendations where appropriate.
• Have experience servicing commercial kitchens similar to yours.

A contractor who understands the entire drainage system—not just the grease trap—can often provide more effective long-term solutions.

Yes. Regular grease trap cleaning helps reduce the amount of fats, oils and grease (FOG) entering the connected drainage system. By preventing grease from accumulating inside pipes, it reduces the likelihood of recurring blockages, excessive wear on the drainage network and costly emergency maintenance.

When grease enters drainage pipelines, it cools and adheres to the pipe walls. Over time, this build-up restricts water flow and traps food particles and other debris, increasing the frequency of blockages and the need for corrective maintenance.

While grease trap cleaning alone cannot eliminate all drainage issues, it forms an important part of a preventive maintenance programme that protects both the grease trap and the downstream drainage system.

In many commercial kitchens, yes. While grease trap cleaning removes accumulated grease and sludge from the grease trap itself, it does not remove grease that has already built up inside the connected drainage pipelines.

Where grease has accumulated downstream, high-pressure water jetting can thoroughly clean the internal walls of the pipes, removing hardened grease and restoring proper flow. Combining both services helps maintain the entire kitchen drainage system rather than focusing on only one component.

The need for jetting depends on the condition of the drainage system, the history of blockages and the amount of grease entering the pipes.

A CCTV drain inspection is recommended when recurring drainage problems continue despite regular grease trap cleaning and high-pressure water jetting. It allows technicians to inspect the internal condition of the drainage system and identify hidden defects that cannot be seen from the surface.

A CCTV inspection may be appropriate when:

• The same drain blocks repeatedly.
• The grease trap overflows despite regular servicing.
• High-pressure water jetting provides only temporary improvement.
• Structural pipe defects are suspected.
• Drainage problems occur without an obvious cause.

The inspection provides visual evidence that helps determine whether the issue is caused by grease accumulation, pipe damage, root intrusion, displaced joints or another underlying condition.

Yes. One of the main advantages of scheduled grease trap maintenance is that it helps reduce unexpected drainage problems that can interrupt kitchen operations.

Blocked drains, overflowing grease traps and emergency plumbing issues often occur during peak operating hours, when they have the greatest impact on staff, customers and business continuity. By maintaining the grease trap on a planned schedule, many of these issues can be prevented before they develop into emergencies.

Planned maintenance also allows servicing to be scheduled during quieter operating periods, reducing inconvenience to daily operations.

Choosing a grease trap cleaning contractor involves more than arranging routine waste removal. An experienced contractor should understand how the grease trap interacts with the entire drainage system and be able to recommend practical solutions when additional issues are identified.

At SPS Jetting, we provide comprehensive grease trap maintenance supported by our expertise in commercial drainage systems. Where required, we can also assist with complementary services such as high-pressure water jetting, CCTV drain inspection, vacuum suction and oil & grease (non-hydrocarbon) sampling and testing, allowing clients to manage their drainage system through a single, experienced service provider.

Our focus is not simply on cleaning the grease trap, but on helping clients reduce recurring drainage problems through preventive maintenance and informed recommendations.