How to Clean Your Grease Trap

Step-by-step grease trap cleaning instructions, maintenance schedules, and compliance tips for commercial kitchens

A properly maintained grease trap prevents drain clogs, eliminates odors, and keeps your kitchen compliant with local FOG (fats, oils, grease) regulations. Most commercial kitchens should clean their grease trap every 1-3 months, or when grease fills 25% of the trap's capacity. This guide covers the complete cleaning process, maintenance schedules, and when to call a professional.

Grease traps are essential plumbing devices that capture fats, oils, and grease (FOG) before they enter your drain lines. When FOG cools, it solidifies and coats the inside of pipes, leading to clogs, sewage backups, foul odors, and expensive plumbing repairs.

Regular grease trap cleaning protects your plumbing, keeps your kitchen smelling fresh, and ensures compliance with local health and environmental regulations. Most municipalities require commercial kitchens to maintain grease traps and keep cleaning records for inspection.

This guide walks you through the complete grease trap cleaning process, from safety preparation to reassembly.

Safety First

Grease trap cleaning involves exposure to bacteria, gases, and slippery surfaces. Take these precautions before starting:

Required Personal Protective Equipment (PPE):

• Rubber gloves (heavy-duty, elbow-length recommended)
• Safety goggles or face shield
• Waterproof apron or coveralls
• Rubber boots or waterproof shoe covers
• Face mask or respirator (hydrogen sulfide gas can accumulate)

Safety Precautions:

• Work in a well-ventilated area or ensure exhaust fans are running
• Never smoke or use open flames near an open grease trap
• Keep a first aid kit nearby
• Have another person aware you're performing the cleaning
• If you smell strong sulfur (rotten egg) odor, ventilate the area before proceeding

Tools and Supplies Needed

Gather these items before you begin:

Tools:

• Pry bar or crowbar (for lid removal)
• Measuring stick or dowel rod
• Heavy-duty scraper or putty knife
• Shop vacuum (wet/dry) or pump
• Buckets (5-gallon recommended)
• Stiff-bristle scrub brush
• Garden hose or pressure washer

Supplies:

• Commercial drain cleaner or degreaser
• Dish soap
• Absorbent pads or cat litter (for spills)
• Heavy-duty trash bags
• FOG disposal container (check local regulations)

How to Clean a Grease Trap: 7 Steps

Step 1: Remove the Lid Carefully

Slowly pry off the grease trap lid using a crowbar or pry bar. Work around the edges evenly to avoid bending the lid or damaging the gaskets.

Important: Gaskets create an airtight seal that prevents odors from escaping. Inspect gaskets for cracks or wear and replace if damaged.

Set the lid aside on a stable surface where it won't get damaged or create a tripping hazard.

Step 2: Measure and Record Grease Levels

Before removing any contents, insert a measuring stick or wooden dowel straight down into the trap. Measure the depth of the grease layer floating on top.

Why this matters: Many municipalities require FOG reports documenting grease levels at each cleaning. This record demonstrates compliance during health inspections and helps you determine optimal cleaning frequency.

Record the measurement with the date in your maintenance log.

Step 3: Remove Standing Water

Using a shop vacuum or small pump, remove the water from the grease trap. Transfer it to buckets or a holding tank.

Save this water. You'll return it to the trap after cleaning. The water creates a seal that prevents sewer gases from entering your kitchen.

Step 4: Scoop Out the Grease

Using a heavy-duty scoop, bucket, or shop vacuum, remove all accumulated grease and solid waste from the trap. Work systematically:

1. Start with the floating grease layer on top
2. Remove solid food particles from the bottom
3. Scrape grease from the sides, baffles, and lid interior
4. Check inlet and outlet pipes for buildup

Place all waste in a sealed container for proper disposal. Never pour grease down any drain or into regular trash.

Step 5: Scrub All Surfaces

With the bulk of the grease removed, scrub the entire interior:

• Use a stiff-bristle brush with dish soap or commercial degreaser
• Clean the lid, sides, bottom, and all baffles thoroughly
• Scrub the inlet and outlet screens
• Remove any remaining residue from corners and crevices

Rinse with clean water, collecting the rinse water for proper disposal.

Step 6: Replace the Water

Pour the water you saved in Step 3 back into the grease trap. This water barrier is essential for:

• Preventing sewer gases from entering your kitchen
• Allowing the trap to begin capturing FOG immediately
• Maintaining proper trap function

If you discarded the original water, add fresh water until it reaches the normal operating level (typically indicated by the outlet pipe).

Step 7: Reinstall the Lid and Verify the Seal

Place the lid back on the grease trap, ensuring it sits evenly on all sides. Check that:

• Gaskets are properly seated
• The lid creates an airtight seal
• No gaps allow odors to escape
• Fasteners or locks are secured (if applicable)

Run water from a nearby sink to verify the trap is draining properly.

How Often Should You Clean Your Grease Trap?

Cleaning frequency depends on your kitchen's FOG production, trap size, and local regulations.

The 25% Rule

The industry standard is the "one-quarter rule": clean your grease trap when FOG fills 25% of the trap's capacity. Beyond this level, the trap loses efficiency and may allow grease to pass through to your drain lines.

Recommended Cleaning Schedule by Kitchen Type

Factors That Increase Cleaning Frequency

• Smaller trap size
• Menu heavy in fried foods
• High daily meal volume
• Older or less efficient trap design
• Hot weather (grease accumulates faster)

Grease Trap Maintenance Schedule

Beyond regular cleaning, follow this maintenance schedule to keep your trap functioning properly:

Signs Your Grease Trap Needs Immediate Cleaning

Don't wait for your scheduled cleaning if you notice these warning signs:

• Slow draining sinks in the kitchen area
• Foul odors coming from drains or the trap area
• Grease visible in sink drains or on the floor near the trap
• Gurgling sounds from drains
• Fruit flies or drain flies around sink areas
• Failed inspection or warning from health inspector

When to Call a Professional

While routine cleaning can be done in-house, certain situations require professional grease trap services:

Call a licensed grease trap service when:

• Your trap exceeds 500 gallons capacity
• You're unable to access or remove the lid safely
• The trap is located underground or requires excavation
• You need certified FOG disposal documentation
• Local regulations require licensed pump-out services
• You notice structural damage, cracks, or leaks
• Persistent odors continue after thorough cleaning

Professional services typically cost $150-$500 depending on trap size and location. Many municipalities require professional pump-outs at specified intervals regardless of in-house cleaning.

FOG Compliance and Record Keeping

The EPA and local municipalities regulate grease trap maintenance to protect sewer infrastructure. Non-compliance can result in fines, business closures, and liability for sewer damage.

What to Document

Maintain a grease trap cleaning log that includes:

• Date of each cleaning
• Grease depth measurement before cleaning
• Who performed the cleaning
• Disposal method and location
• Any repairs or issues noted
• Professional service receipts (if applicable)

Common Compliance Requirements

While regulations vary by location, most jurisdictions require:

• Grease traps for all commercial food preparation facilities
• Regular cleaning (typically quarterly minimum)
• Proper FOG disposal through licensed haulers
• Maintenance records available for inspection
• Grease trap sized appropriately for your operation

Contact your local water authority or health department for specific requirements in your area.

Related Guides

• Floor Troughs & Drains - Manage water drainage in commercial kitchens
• Commercial Dishwashers - Dishwashers for commercial kitchens
• Janitorial Supplies - Cleaning supplies for commercial kitchens

Shop Grease Traps and Maintenance Supplies

Keep your kitchen compliant and drains flowing with the right equipment:

• Grease Traps & Interceptors - Code-compliant grease interceptors for every kitchen size
• Drain Cleaners & Openers - Commercial-grade drain maintenance products

Share This!