A grease trap intercepts fats, oils, and grease (collectively called FOG) before they enter the public sewer system. PUB requires this for all food production operations in Singapore. Without a functioning, correctly sized grease trap, you face PUB enforcement action, drain blockages that cause flooding or odour, and complications during SFA licensing. The trap is not an optional add-on. It is infrastructure that must be in place before you apply for your food factory licence.
Understanding grease trap basics before viewing a unit helps you avoid committing to a space with expensive hidden problems.
Types of Grease Traps
Under-sink or point-of-use traps. Small units installed directly at wash hand sinks or pre-rinse stations. These handle minimal FOG loads and are only suitable for very light operations: a single prep sink or hand wash station. They are not a replacement for a full production-scale grease trap and will not satisfy PUB requirements for a cooking operation.
In-ground grease interceptors. Larger capacity units installed below floor level, typically with multiple chambers that allow FOG to separate from wastewater as it flows through. These are the standard configuration for food factories with meaningful cooking output. Capacity ranges from small domestic-scale units to commercial units sized for high-volume operations. Installation requires cutting into the floor slab and connecting to the drainage system below.
Above-ground grease traps. Used when in-ground installation is not feasible, typically in upper floor units where cutting into the floor slab is not permitted or structurally impractical. Above-ground traps are typically larger, single-chamber units that require floor space within the unit. They are less common and may require additional pumping infrastructure depending on the drainage configuration.
Sizing is determined by the anticipated FOG output from the operation. PUB publishes sizing guidance based on the number and type of fixtures connected. Undersized traps overflow, sending FOG into the public drainage system and creating PUB compliance risk. Oversized traps are costly to install and maintain unnecessarily.
Common Gotchas
Existing trap undersized for your volume. The most common problem. The previous tenant may have run a lower-volume operation (one or two meal preparations a day, for example) and the trap was sized accordingly. Your production schedule, especially if it involves continuous cooking or high-volume batch preparation, may exceed that capacity. Always verify trap capacity against your planned output, not the previous tenant’s.
Trap in poor condition. Cracked, corroded, or poorly maintained traps require expensive replacement. A crack in the body of an in-ground trap usually means the entire unit must be excavated and replaced. Maintenance records from the previous tenant or building management may indicate the trap’s age and condition. If records do not exist, treat the trap as suspect until a professional inspection confirms otherwise.
Location inconvenient for your layout. Trap location is determined by the building’s drainage configuration and may not align with your planned production layout. A trap located at the far end of the unit from your main wash area requires long drain runs, which can cause FOG to cool and solidify in the pipework before reaching the trap, defeating the purpose of the installation. Factor trap location into your layout planning.
Access for cleaning. Grease traps require regular cleaning, typically weekly to monthly depending on volume. The trap chamber must be accessible for pump-out and inspection. A trap buried under equipment, surrounded by fixed joinery, or behind a locked partition creates a maintenance nightmare and may not meet PUB’s access requirements. Confirm access arrangements during viewing.
Upper floor structural modification. Installing an in-ground grease trap on an upper floor may require cutting into the concrete floor slab, which can affect structural integrity and requires building management and possibly BCA approval. In some buildings, this is explicitly prohibited. If no trap exists and in-ground installation is not possible, above-ground installation or a licensed pumping arrangement may be required, each with its own cost and operational implications.
Maintenance Reality
Grease trap cleaning is not optional and not a one-time event. The trap must be pumped out regularly. The frequency depends on usage volume and trap capacity, but monthly is common for active production kitchens, and some high-volume operations require more frequent service.
PUB can inspect trap condition and cleaning records during routine checks or in response to a drainage complaint. Retained records (service invoices, pump-out logs) demonstrate compliance. Without records, you have no proof the trap has been maintained.
FOG disposal must be handled by a licensed waste collector. The collector provides the waste transfer documentation that accompanies each pump-out. Engage a provider with experience in food service FOG waste, and confirm they are licensed by NEA.
What to Check During Viewing
Before committing to a unit, ask building management the following:
- Is there an existing grease trap? What type and rated capacity?
- When was it last cleaned and serviced?
- Where is the trap located relative to the planned production and wash areas?
- Is there clear access for cleaning and pump-out equipment?
- If no trap exists, is in-ground installation feasible in this unit?
- What has building management approved for grease trap installation in this building?
Summary and Closing
A grease trap is not a box you tick and forget. It must be sized for your output, maintained on schedule, and accessible for service. If the existing trap is wrong for your operation (undersized, poorly located, or past its service life), the cost of replacement or augmentation falls on you after you have signed the lease.
References
- PUB — Drainage Connection Requirements — Grease trap specifications and sizing
- SFA — Food Factory Licensing — Food safety requirements related to drainage
- PUB — Trade Effluent — FOG disposal and licensing requirements
- BCA Building Control — Structural requirements for grease trap installation
- NEA — Environmental Public Health — Waste management standards for food establishments
- SFA — Food Manufacturing — Food factory infrastructure and hygiene standards
- NEA — Vector Control — Pest and waste management standards
- JTC — Space for Rent — Purpose-built food factory listings