Do All Restaurants Need a Grease Trap? Legal Requirements Explained

There’s a lot to think about when you own or manage a restaurant and its busy kitchen. Aside from the day-to-day need to ensure your customers are served great food, there are supply considerations, the need to keep your menu fresh, staffing issues and a whole deluge of other concerns.

Something that may not be so obvious if you’re new to the industry is that your kitchen likely needs a grease trap installed to be in line with legal requirements regarding how you deal with waste created during the hot food cooking process. In this article, we’ll explain your responsibilities surrounding grease traps for restaurants.

What is a Grease Trap In a Restaurant?

How Does a Grease Trap Work?

Why Are Grease Traps in Commercial Kitchens Important?

Are Grease Traps a Legal Requirement for Restaurants?

What Happens If a Restaurant Doesn’t Have a Grease Trap?

Grease Trap Cleaning

Grease Trap Pumping

Grease Trap Maintenance

How to Install a Grease Trap

How to Size a Grease Trap

Restaurants Grease Trap FAQs

A restaurant grease trap intercepts fats, oils and grease (FOGs) to prevent them from entering the sewer system. 

They exist in a number of configurations and form factors to suit a range of different kitchen sizes and business types, from smaller units that fit under sinks, such as the Big Dipper range, to larger, underground tanks that can cope with a much greater flow of wastewater, including the Trapzilla series of units.

They can also vary between manual and automatic operation, meaning the range of suitable grease trap types for restaurants is quite large.

Restaurants deal with a large quantity of food particles that pose a threat to their drainage systems. While some of it can be easily discarded, small food particles can begin to accumulate. 

What a restaurant grease trap does is keep the water flowing through the drainage systems. The design enables food particles to sink to the bottom, while grease floats to the top and water flows through the outlet pipe into the sewage system. For additional information, check out our guide on ‘How Does a grease trap work’.

Restaurant kitchens produce many waste products, among them the remnants of the fats, oils and grease (FOG) used in the cooking process. This FOG, if not intercepted, can make its way into the sewer system where it congeals and combines with other waste to create serious blockages and even so-called ‘fatbergs’ that can cause significant disruption.

Grease traps are important because they capture FOG and remove it from wastewater before it gets to the sewer. This is essential to keep sewers flowing freely, and it’s also a legal requirement. Now that we’ve covered why grease traps are vital, let’s clarify which restaurants must have them to meet legal requirements.

Yes, grease traps are a legal requirement for restaurants and commercial businesses that serve hot food. This is a direct result of the damage FOGs can create in a sewer system. Without a grease trap, drainage systems are susceptible to blockages, fatbergs and severe damage to pipes. Not only is it costly to repair these issues, but it can also be a nightmare from a hygienic standpoint. 

The legislation surrounding grease management is largely governed by the Water Industry Act 1991, specifically Section 111. Under this law, businesses that serve hot food have a legal obligation to prevent FOGs from entering the sewer system. 

Local authorities and water companies are responsible for enforcing these regulations. If a business is found to be discharging FOGs into the sewer network, it can face enforcement action, fines or even prosecution.

The crux of the question is whether you cook hot food or not. Hot food cookery generates a lot of fats, oils and grease that must be filtered from your wastewater before it enters the sewer. Even if you serve your food cold, if it’s been cooked as part of the creation process, a grease trap is required.

Do all restaurants need a grease trap? Yes, in most cases, if your kitchen involves any form of hot food cooking, you require a grease trap. 

There are some very rare exceptions. For example, premises that do not cook food on site, such as those only serving pre-packaged cold food or drinks, may not produce enough FOG to require a grease trap. However, these cases are rare, and even minimal food preparation produces enough particles that can generate grease.

Not having a grease trap in a restaurant leaves you and your business susceptible to a wide range of problems. 

Blocked pipes can pose a hygiene issue, emit unpleasant odours, and compromise your sink’s performance. Commercial kitchens impacted by blockages can experience expensive downtime. Grease traps are the ultimate safeguard against FOGs and prevent costly damage to your pipes.

One of the last things any restaurant wants is a sink that emits unpleasant odours. It’s not a pleasant condition for staff to be exposed to and can lead to several health and safety violations. 

Not having a grease trap isn’t just an isolated issue, it’s absence results in several different issues, including pests being attracted by the odours. Not only do pests create an unpleasant working condition, but they also pose serious hygiene risks, increase the likelihood of contamination, and can lead to enforcement action or even closure by environmental health authorities.

Any restaurant owner focused on their bottom line needs a grease trap for several reasons, including the risk of costly fines. Failure to properly manage FOGs can result in penalties from local authorities or water companies.

Compliance with FOG regulations is mandatory – having a grease trap or other form of grease management device is essential. Investing in proper grease management shows due diligence and protects your business from legal fines and potential prosecution.

By not having a grease trap installed, your commercial restaurant puts itself at severe risk of closure. This is due to the various safety hazards, environmental damage and hygienic issues it can cause. Failure to meet these standards can result in temporary or even permanent shutdown. 

It’s not enough to just have a grease trap installed. They require cleaning and maintenance to maintain hygienic standards. 

Grease traps quickly lose their efficiency when they are not looked after, which is why we offer a pre-planned maintenance service to maintain their performance. 

Hygiene should always be of the utmost importance in your kitchen. Without regular cleanings, drainage systems can be a breeding ground of bacterial growth. 

Failure to meet BS EN 1825-1:2004 requirements can result in fines, enforcement action, or operational restrictions. Businesses must ensure grease traps are correctly specified, installed and maintained to remain compliant with industry standards.

The frequency of cleaning will very much depend on the nature of your business and the volume of FOG you generate on a daily basis. We’ve provided this helpful chart to give you a general sense of the grease trap requirements for restaurants.

Essentially, grease traps should be cleaned when the combined layer of fats, oils, grease and settled solids reaches 25% of the total capacity of the unit. This proactive approach helps ensure traps continue to operate efficiently and meet regulatory standards. 

Some common signs may indicate your restaurant is due for a grease trap cleaning. Once you start to notice strong odours emanating from the sink, slow drainage or gurgling pipes, then grease may potentially start overflowing with your regular wastewater into the sewer system. 

Once you start to notice any of these signs, it’s best to schedule a grease trap cleaning as soon as possible. 

Grease trap cleaning is a straightforward process. It involves accessing the unit, scooping accumulated grease and solid waste, and cleaning internal components such as baffles and walls. However, this differs from grease trap pumping.

Grease pumping uses specialised vacuum equipment to completely empty a grease trap or interceptor. As grease can harden over time, engineers may use additional tools to break it down before extraction, ensuring effective removal. 
Once fully cleared, the collected waste is transported to an approved disposal or recycling facility, helping businesses remain compliant and maintain system performance.

Maintenance is fairly simple, it just requires a proactive approach and consistent routines. For starters, regular inspections to ensure grease levels have not built up to the point where they can enter the drainage system. This type of preventative maintenance plays a key role in keeping the unit clean, efficient and fully operational.

It is also important to maintain accurate records of inspections and cleaning schedules, helping businesses stay organised and proactive. These records support regulatory compliance and provide clear evidence of due diligence during inspections or any enforcement action.

There are several clear signs that your restaurant may need a grease trap installing. Strong odours coming from sinks, slow drainage or gurgling pipes can all indicate a build-up of FOG within the system. If left unaddressed, this grease can begin to overflow with wastewater into the sewer network.

At the first sign of these issues in a kitchen without a grease trap, it is important to arrange a professional installation as soon as possible to prevent further complications. Ensuring your grease trap is properly installed and maintained by professionals is one of the most proactive measures a business can take to avoid problems altogether. 

There are a few simple steps you can take to ensure you have the right grease trap size for your commercial establishment. Starting with the number of covers served per day, the flow rate of sinks and whether commercial dishwashers are in use. 

Higher volumes of food service and faster water flow increase the amount of FOGs produced, meaning a larger capacity unit may be required. It’s important to consult with an expert regarding your grease trap installation so you choose a size that’s suitable for your restaurant. 

Use our FREE grease trap size calculator for more detailed information.

Need help choosing the right grease trap for your restaurant? Visit our dedicated Grease Traps for Restaurants page to compare systems, calculate the correct size and arrange a free site survey.

From popular under-sink grease trap models like the Big Dipper range and its myriad automatic features to super capacity underground solutions for the busiest kitchens, Aqua Mundus can recommend the ideal solution for your business based on efficiency and budget, and it all starts with a free grease trap site survey.

With Aqua Mundus, staying compliant and efficient has never been easier, so contact us today to keep your kitchen running smoothly and sustainably.