Grease Traps vs Grease Interceptors

If you run a restaurant or food service business in Portland, you know that keeping your kitchen clear of fats, oils, and grease (FOG) is crucial, especially to keep your doors open. Grease traps and grease interceptors are designed to do exactly that.

But here’s the thing: many business owners don’t realize there’s a big difference between grease traps and grease interceptors. We’ve seen firsthand how choosing the wrong one can lead to messy (and expensive) problems.

What is the difference between a grease trap and a grease interceptor?

The main difference between the two comes down to size and location. Grease traps are installed indoors and handle smaller amounts of grease. Grease interceptors are installed outdoors and can handle much larger volumes.

A grease trap is smaller and sits under your sink or near your dishwasher. It’s compact, usually holding between 10 to 30 gallons, and works great for smaller operations.

Grease interceptors are larger and are installed underground outside your building. They can hold anywhere from 250 to several thousand gallons, depending on site needs and local regulations, and are built for heavy-duty operations that produce a lot of grease daily.

How They Work

Both systems work on the same basic principle. They slow down wastewater FOGs, which separate and float to the top. 

When hot, greasy water from your kitchen enters the trap or interceptor, it cools down. As it cools, the grease naturally rises while food solids sink to the bottom. The relatively clean water in the middle then flows out to your septic system or city sewer.

Grease traps use a series of baffles (like walls inside the trap) to slow water flow and give grease time to separate. Since they’re smaller, they need cleaning more often (usually every few weeks or monthly). Grease interceptors work the same way, but on a larger scale. Their bigger size means wastewater has more time to cool and separate. This makes them more efficient at removing grease, but they still need regular pumping (typically every three months).

Do I need a grease trap or a grease interceptor?

The answer depends on your business size and local regulations. Here in Portland, most cities have specific requirements based on how much grease your business produces. Small cafes or delis might get by with a grease trap, while full-service restaurants almost always need an interceptor.

Your local health department will tell you exactly what you need. They look at factors like how many meals you serve, what type of food you prepare, and your kitchen equipment. Professionals like Speedy Septic can also help you determine which system will work best for your business.

Does a commercial dishwasher need a grease trap?

It depends on where your business is. Many jurisdictions require dishwashers to have their own small grease trap or to connect to your main grease removal system. The hot water from dishwashers can actually cause problems by melting grease that’s already trapped, allowing it to flow downstream where it can cause clogs.

Commercial dishwashers themselves don’t produce much grease, they’re mainly dealing with leftover food particles.

However, if your dishwasher connects to the same drain line as your prep sinks or other grease-producing equipment, then yes, you’ll need some grease management.

Does a 3-compartment sink need a grease trap?

Absolutely. Three-compartment sinks are grease magnets. They’re where you wash pots, pans, and dishes that are covered in cooking oils and food waste. Without proper grease management, all that FOG goes straight into your plumbing.

Most health codes require three-compartment sinks to connect to either a grease trap or interceptor. The size depends on your overall kitchen operations, but don’t skip this requirement.

We’ve seen too many restaurants face hefty fines and emergency plumbing bills because they thought they could get away without proper grease control.

Does a grease trap need to be vented?

Yes, proper venting is essential for any grease trap. Without venting, you’ll face slow drainage, gurgling sounds, and potentially dangerous sewer gases backing up into your kitchen. The vent allows air to enter the system, which helps water flow smoothly and prevents vacuum formation.

Venting also helps control odors, something your staff and customers will definitely appreciate. A properly vented grease trap should have a vent pipe that extends through your roof, just like your other plumbing fixtures.

Our Proven Process

At Speedy Septic, we’ve developed a systematic approach to grease management that keeps Portland restaurants running smoothly: 

1. Our process starts with a thorough inspection of your current system. We check trap capacity, measure grease levels, and look for any signs of wear or damage.
2. Next, we pump out all accumulated grease and solids using our specialized equipment. But we don’t stop there!
3. We also pressure wash the interior walls and baffles to remove stubborn buildup. This thorough cleaning extends the life of your equipment and improves its efficiency.
4. Finally, we perform a detailed inspection to make sure everything’s working properly. We check inlet and outlet pipes, test the baffles, and make sure your system meets all local codes. If we spot any issues, we’ll let you know right away and provide recommendations for repairs.

Keep Your Business Clean and Compliant

Managing grease doesn’t have to be a headache. With regular maintenance from Speedy Septic, you can focus on running your restaurant while we handle the dirty work. Our team understands the unique challenges Portland businesses face, from busy tourist seasons to strict environmental regulations.

Speedy Septic is your partner in keeping your kitchen compliant and your plumbing flowing freely. Our technicians arrive on time, work efficiently, and always clean up after themselves. Plus, we keep detailed records of every service, making health inspections a breeze.

So don’t wait until you have a grease emergency! Let Speedy Septic create a customized maintenance schedule that fits your business needs and budget. Get started today by reaching out to our team.

Back to Grease Trap Pumping