How Often Should a Grease Trap Be Emptied? A Must-Know Guide for Businesses

Installing a grease trap and keeping it in full working order is a legal requirement for hot food kitchens in the UK. Across the many makes and models available, it’s essential for kitchen managers and restaurant owners to understand just how often a particular trap should be emptied. This will vary based on how your kitchen operates, the size of your trap, the amount of fats, oils and grease (FOG) you produce and other considerations.

To keep you on the right side of the water company inspectors – and the law – the wastewater experts here at Aqua Mundus have compiled this guide answering the question, “How often should a grease trap be emptied?”

Without regular emptying, cleaning and servicing, the efficiency of a grease trap can diminish until it stops working effectively altogether. This can be bad for several reasons. Firstly, kitchen effluent can block your pipes and back up into sinks, causing significant hygiene issues and possible downtime for your kitchen.

Secondly, an overfull grease trap can allow FOG to pass into the sewer, where it solidifies and causes broader drainage issues. In extreme cases, it may even contribute to fatbergs — massive blockages that can shut down a whole sewer. These can be costly to remove and lead to untold environmental damage. Water companies can seek compensation from any businesses that contribute to their formation.

Finally, because of the legal requirements of fitting a grease trap, not fitting one or failing to keep it in working order can lead to significant fines and even prosecution.

Most commercial grease traps should be emptied every one to three months. High-usage kitchens may require monthly cleaning – something we provide as part of our pre-planned maintenance packages – while smaller sites can leave longer between cleans.

Following this guideline helps prevent overflows, odours and compliance issues – but it’s important to remember that every kitchen is different, and you need to check your grease trap manually to determine the correct frequency of cleaning.

How often your grease trap needs emptying can be influenced by many variables, including trap size, daily meal volume, type of food prepared and whether you use a biological dosing system alongside your grease interceptor. A busy kitchen serving greasy food will fill a trap faster than a smaller site dealing in lighter meals.

Foul smells in your kitchen, slowly draining sinks or overflows from your grease trap are all signs that it’s overdue for an emptying and cleaning. If the device isn’t functioning correctly, you can even notice visible grease buildup in pipes and around sinks. Regular checks and spotting these warning signs help you act before minor issues become costly emergencies.

As we’ve mentioned, an overflowing grease trap can cause foul smells, backflow into sinks and potentially contaminate food preparation areas. This brings a serious hygiene risk for staff and customers, increasing the likelihood of illness, pest infestations and failed health inspections – all of which could result in temporary closure or long-term reputational damage.

Failing to maintain your grease trap is a breach of UK waste legislation. If FOG enters the sewer system, you risk contributing to fatbergs and environmental damage, which can lead to prosecution and hefty fines. These avoidable events cost water companies millions, and they’re cracking down on those who cause them; it’s not difficult for them to trace non-compliance back to the source.

Whether you’re a small café or a large commercial kitchen, our mission here at Aqua Mundus is never to scaremonger, but to explain the facts and offer solutions. If waste management and grease trap cleaning isn’t your forte, we offer a wide range of services that can shoulder the burden for you, including grease trap installation, repair and servicing.

Fancy a conversation? Get in touch with us today on 01386 832205, email sales@aquamundus.co.uk or use our online contact form, and we’ll be in touch to make grease trap emptying simple.