Grease Trap Frequently Asked Questions

Grease traps play an important role in kitchens everywhere. If you’ve owned or worked in a restaurant, you probably know what a grease trap is and what it does. If not, you might be wondering, “What is a grease trap?” You’ll find the answer to that question, as well as the answers to 10 other common grease trap frequently asked questions, in the article below.

And if you have any questions about grease traps that are not covered in this article, please contact us. We’ll be happy to help you get the answers you need.

What is a grease trap?

A grease trap is a container that collects the fats, oils, and grease, a.k.a. FOG, that finds their way down the drain during everyday kitchen operations. It’s a critical choke point of a building’s outbound sewage system.

Depending on the size and efficiency of the device, a grease trap can be located either outside and underground or inside near a grease-producing area, such as a sink. Grease traps can be made from a variety of materials, including plastic, concrete, cast iron, and stainless steel.

Why do I need a grease trap?

Grease trap installation is required for food service establishments and the like. Other businesses that are required to have grease traps include hospitals, movie theaters, and cafeterias. This is to limit the amount of FOG that gets passed through water treatment facilities.

Even if your restaurant doesn’t have a deep fryer, you still need a grease trap. It’s a common misconception to think otherwise. All food service establishments, even those without deep fryers, produce FOG to some degree.

Why is grease a problem?

A little grease can cause a whole lot of problems. For starters, when grease ends up going down the drain, it can cool and harden, causing clogs.

Grease can also cause blockages in sewer collection lines. If a blockage occurs, it can result in an overflow of wastewater from the collection system. Overflows such as these can result in damage to property, as well as the contamination of nearby bodies of water.

How does a grease trap work?

Grease traps are holding tanks that separate FOG present in the wastewater produced by kitchen appliances such as sinks and dishwashers, as well as floor drains.

Grease traps work by slowing down the flow of wastewater, giving it time to cool. As the wastewater cools, FOG floats to the top of the grease trap, allowing for easy removal.

Meanwhile, the separated water sinks to the bottom of the trap and out into the municipal water supply. The direct connection between grease traps and water supplies is the primary reason why grease traps are closely monitored by city and environmental regulations.

How do you clean a grease trap?

There are two methods of cleaning, or pumping, a grease trap. The preferred method is known as pump and return. This two-part method involves removing FOG for disposal and returning the leftover gray water back into the grease trap.

Though pump and return is the more optimal way to clean a grease trap, not all service providers offer it. This is because it requires specialized vehicles.

The second method is known as dry pumping, which is less optimal but does not require specialized vehicles. Dry pumping entails removing the entire contents of the grease trap, both FOG and gray water.

The reason why dry pumping is less optimal is because it temporarily leaves the grease trap dry. A dry grease trap can emit strong odors until water is introduced again.

Some cities mandate one method of grease trap pumping over another. If this is the case, it’s important to find a service provider capable of performing the type of service mandated in your area. Otherwise, it’s a matter of preference.

Can I clean my own grease trap?

In some cases, yes, you can clean your own grease trap. However, it’s recommended that you leave grease trap cleaning to the professionals.

Employees often do not clean grease traps properly, which can result in damage to the device or even hefty fines. You’re also required to properly dispose of the material that’s been cleaned out of the grease trap, as well as keep records of each cleaning.

A major upside to a professional grease trap cleaning is that the service technician will be able to notify you of any visible damage to your grease trap. This can reduce the likelihood of having to make costly repairs.

How often does my grease trap need to be cleaned?

There’s no easy answer to this question, as it varies based on multiple factors. For instance, some establishments, such as busy restaurants, need to have their grease traps cleaned as often as every three weeks. Other places can go longer between grease trap cleanings. The size and efficiency of your grease trap matters too, of course.

No matter what, though, a grease trap must be pumped once it is 25% full of FOG. This is often referred to as either the one-fourths or one-quarter cleaning rule. If FOG makes up more than 25% of the contents of a grease trap, the grease trap will no longer work as intended.

What are some ways to keep my grease trap clean?

There are a variety of ways you can keep your grease trap clean. First and foremost is preventative maintenance. By having your grease trap regularly serviced by a knowledgeable service provider, such as ARP Environmental Solutions, you’ll prevent harmful buildup that can reduce the lifespan of your grease trap.

Another way to keep your grease trap clean is to train your employees on the proper handling of grease and food waste. This includes planning for potential spills where a deep fryer is located and scraping leftover food of off plates into the trash before rinsing.

Just like grease should never be poured down the drain, neither should food. Even if a sink has a garbage disposal, you should not assume that it will be powerful enough to effectively break up solid materials.

How much will I be fined if my grease trap overflows?

There is no clear-cut answer to this question, as the fine generally varies by municipality. However, several factors are taken into consideration when determining the cost of the fine. These factors include if grease trap services have been regularly performed, if the grease trap samples exceed FOG limits, and the number of previous overflows.

Why does my grease trap smell after being cleaned?

If your grease trap is emitting an odor after being cleaned, it could be due to a number of factors.

Did the smell occur right after a grease trap cleaning was performed? If so, it’s likely that your grease trap was dry pumped, and the smell will soon dissipate once water is reintroduced into the grease trap.

On the other hand, if time has passed since your grease trap was cleaned, the smell could instead be the result of a larger issue. Possible causes include a worn or corroded gasket around the manhole cover, or a backup in the line to the grease trap caused by FOG and solid materials.

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

The terms “grease trap” and “grease interceptor” are often used interchangeably, with “grease trap” being the more common of the two. However, the actual difference between grease traps and grease interceptors has to do with the flow rate of wastewater the device can handle.

According to the Uniform Plumbing Code, or UPC, grease traps have a flow rate of less than 50 gallons per minute, while grease interceptors have a flow rate of more than 50 gallons per minute.

Hopefully this article helped to answer some grease trap frequently asked questions. If you think it’s time to have your grease trap professionally cleaned, please contact us here or by phone at 773-563-4543.