Common Problems with Grease Traps and How to Fix Them

From fast food franchises to Michelin-starred restaurants, all commercial hot food kitchens are legally required to install a grease trap. However, blocked grease traps can be a real nightmare, posing a health and safety risk and causing whole kitchens to come to a standstill. Without prompt response, blocked grease traps or leaking grease traps can spiral into costly issues.

Understanding what’s going wrong is the first step to fixing it. In this guide, the grease management experts at Aqua Mundus break down the most common grease trap problems and explain how to avoid downtime while keeping your kitchen legally compliant, efficient and odour-free at all times.

A grease trap is an interceptor device fitted to your wastewater line that separates fats, oils and grease (FOG) from your kitchen effluent before they reach the sewer, where they can potentially cause serious blockages known as ‘fatbergs’.

Legally required in commercial kitchens that cook hot food, they’re essential for preventing blockages, foul smells and environmental damage.

Learn more about what a grease trap is and how it works in our blog post.

Grease trap blockages are normally related to one of a few issues, including: 

One of the most common grease trap problems is slow-draining sinks, which are usually caused by excessive fats, oils and grease or food sediment clogging up your pipes and trap. If solid waste bypasses your sink strainer or builds up too quickly, it can restrict flow through the trap entirely.

The easiest fix is prevention – regular cleaning, routine checks and basic staff training go a long way to avoiding blockages. Adding simple strainers to your pot-wash sinks and pre-rinsing dishwasher-bound items also reduces the risk of food waste entering the system in the first place.

There are a few key signs that your grease trap is likely blocked, including: 

If your grease trap is overflowing or has become blocked, there are some easy steps you can take: 

One of the most noticeable grease trap problems is foul odours. If your grease trap smells awful, it’s often down to a mix of trapped food particles, rotting FOG and bacterial buildup. The rotting materials produce hydrogen sulphide gas, which is toxic in large amounts. It might mean that seals are broken, the trap is overdue for a clean, or that the unit has reached the end of its life.

Deep cleaning is the first step, but installing a biological dosing system can help reduce long-term smells too. Also, make sure the unit is fully sealed and vented to prevent gases from escaping into your kitchen. If the unit is corroded or damaged, it may be time to replace the whole unit too.

If your grease trap keeps overflowing, chances are it’s either full, too small for your kitchen output or is not being cleaned and emptied often enough. An undersized unit will reach capacity much faster than expected. If your unit is old, it may be time to consider a bigger, more modern unit.

It’s essential to plan and stick to a regular cleaning schedule. If your grease trap keeps overflowing after implementing this, your cleaning and emptying schedule either needs to be more frequent, or the unit may no longer be suitable for the amount of FOG your kitchen generates.

There are a few reasons that a grease trap might overflow, such as: 

If your grease trap is repeatedly overflowing, try these simple steps: 

Leaking grease traps are usually related to one of five causes: 

How to fix a leaking grease trap (temporary fixes): 

For a permanent fix, you’ll need to contact a professional grease trap repair provider.  

To find the source of the leak in your grease trap, look for: 

When water enters the trap too quickly, it can prevent grease from separating out correctly. This can result in grease bypass. Broken baffles (the walls that slow down the flow of water inside the trap), incorrect installation or poor flow control can all result in poor FOG capture. Again, the trap may be too small for your needs. If your grease trap is not capturing grease as it should, you could be flushing grease into the public sewer network, which is a major compliance issue. 

Check the baffles and the flow control valve during regular cleaning and maintenance. In some cases, you may need to reduce the water flow or even reposition the unit entirely. A professional inspection will pinpoint installation issues – get in touch with us, and we’ll be happy to help.

If grease trap problems are ignored and the unit isn’t cleaned, maintained and serviced regularly, blockages may occur further down the line, which can quickly lead to serious fines and even prosecution from the water company. Failure to keep waste transfer notes risks enforcement action.

Familiarise yourself with your local grease regulations, waste transfer and disposal facilities and keep detailed maintenance records. Partnering with a professional service provider for pre-planned maintenance services ensures you stay compliant and avoid costly penalties at all times.

The Water Industry Act governs drainage, wastewater and water pollution, and includes specific directions and requirements for commercial sites in Section 111. Any breach of these terms can result in a Section 111 Notice being issued to the owner or operator of the commercial site. Section 111 states that it’s illegal to discharge anything into the public sewer that can: 

Improper FOG disposal can cause a range of environmental risks, from sewer blockages and water pollution to soil contamination and even air pollution. Capturing and disposing of FOG appropriately is critical for environmental protection as well as legal compliance. 

In many cases, the best solution to grease trap problems is to call a professional. Given the risk for compliance issues, hygiene concerns and environmental damage, professional grease trap support is the safest, most cost-effective solution. 

If you’re experiencing leaky, damaged or blocked grease traps, contact the expert team at Aqua Mundus today by calling 01386 832205, emailing emailus@aquamundus.co.uk or filling out our contact form. 

There are a few signs that your grease trap needs more urgent attention, and you should keep a close eye out for them:

In some cases, you may need emergency grease trap cleaning to address the issue. A clogged, leaking or damaged grease trap can be a risk to your business’ continuity and compliance. 

If you notice any signs of leaking, unpleasant smells, blockages or slow draining, and none of the simple fixes in this guide have helped, contact Aqua Mundus for emergency grease trap cleaning now. Our 24-hour service team is always on-hand to provide the support you need. Just call us on 08456 440 630.  

Regular cleaning and maintenance is the only way to avoid most common grease trap problems. Make sure your cleaning schedule is appropriate to the amount of FOG your kitchen produces, and clean and empty your trap at least every one to three months. 

Whether you need emergency response or repairs, leak investigation or long-term maintenance contracts, Aqua Mundus can help. 

Our expert team of grease trap technicians works nationwide to support businesses like yours, keeping them operational and compliant. Whatever your grease trap needs, contact us today by calling 08456 440 630, emailing emailus@aquamundus.co.uk or filling out our contact form.