How often should a commercial grease trap be emptied?

It depends on your kitchen volume and trap size. Busy restaurants typically need weekly or fortnightly emptying. Smaller cafes or pubs might manage with monthly service. The general rule is to empty when the trap is 25% full of grease - if you're seeing grease in places it shouldn't be, or noticing bad smells, you probably need more frequent emptying.

How much does grease trap cleaning cost?

Pricing depends on your trap size and location. Most commercial grease trap cleans cost between £150 and £350 per visit. We'll give you a fixed quote based on your specific setup - the price we quote is the price you pay.

Is a grease trap a legal requirement in the UK?

If your business serves hot food, UK Building Regulations require your drainage to have a grease separator or other effective means of grease removal. While there's no single law saying 'you must have a grease trap,' you can face significant fines if grease from your premises causes sewer blockages. The Water Industry Act 1991 makes it a criminal offence to allow matter into drains that impedes flow.

What happens if I don't clean my grease trap?

An unmaintained grease trap stops working. Grease passes straight through into your drains, causing blockages in your pipework and potentially in the public sewer. You could face drainage emergencies, bad smells in your kitchen, visits from environmental health, fines from your water company, and even prosecution under the Food Safety Act if it affects hygiene.

What are the signs my grease trap needs emptying?

The main signs are slow-draining sinks, bad smells from drains or the trap itself, grease appearing around sinks or in areas it shouldn't be, and it being more than a month since your last clean. If you're noticing any of these, your trap likely needs attention.

Do I need waste transfer notes for grease trap waste?

Yes. Grease trap waste is classified as controlled waste under UK law. You must use a licensed waste carrier, and they must provide waste transfer documentation. Environmental health officers can request to see these records, and failure to produce them can result in a £300 fixed penalty or prosecution.

Can you clean grease traps outside normal hours?

Yes. We understand that grease trap cleaning during service hours isn't ideal - the smell and disruption can affect customers. We regularly clean traps early morning before kitchens open, late evening after closing, or on quieter trading days. No premium for out-of-hours visits.

What's the difference between a grease trap and a grease interceptor?

They do the same job - separating fats, oils, and grease from wastewater before it enters the drainage system. 'Grease trap' usually refers to smaller units fitted under sinks or in the kitchen. 'Grease interceptor' typically means larger units installed outside or underground. Both need regular emptying and cleaning.

How do I know what size grease trap I need?

Trap size depends on your kitchen's flow rate - essentially, how much wastewater you produce. Factors include the number of sinks, dishwashers, and other equipment, plus your meal volume. If you're not sure whether your current trap is adequate, we can assess it and advise.

Can you install a new grease trap?

Yes. If you need a grease trap installed, replaced, or upgraded, we can handle the full job - from sizing and specification through to installation and first service. We'll make sure it meets EN 1825 standards and is properly connected to your drainage.

Can you set up a regular grease trap cleaning schedule?

Yes - that's what most of our restaurant and food business clients do. We'll agree a schedule based on your trap size and kitchen volume, then contact you before each visit to arrange access. You'll get consistent service, proper documentation, and one less thing to manage.

Commercial grease trap management

Keep your kitchen compliant and your drains clear.

Regular emptying and cleaning to prevent blockages

Full compliance with UK regulations and waste disposal laws

Scheduled services that work around your trading hours

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Why choose OneFlow?

based on 180+ Google reviews

No callout fees

You only pay for the grease trap service itself. No charge for site visits, inspections, or quotes. Simple pricing that helps you budget accurately.

Fixed pricing

We quote a fixed price based on your trap size and service frequency. No surprises, no extras. The price we agree is the price you pay, every visit.

Flexible scheduling

We work around your kitchen hours. Early mornings before service, late evenings after closing, or quieter days mid-week. Minimal disruption to your trading.

Full compliance

Every service comes with waste transfer documentation as required by law. Ready for environmental health inspections, insurance, or your own records.

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Grease traps cleaned in under an hour

On site, emptied, cleaned, and documented - with minimal disruption.

98%

Of customers would recommend us.

6000+

Jobs completed last year alone.

Reliable service for busy kitchens

Running a commercial kitchen means managing dozens of competing priorities. Grease trap maintenance shouldn't be something you have to think about - until it goes wrong and you're facing blocked drains, bad smells, or an environmental health visit.

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Scheduled maintenance you can forget about

We'll set up a regular cleaning schedule based on your trap size and kitchen volume. We track when you're due and contact you to arrange access. One less thing on your list.

Same engineer, at every visit

You'll see the same familiar face each time. Someone who knows your kitchen, your trap, and your schedule. No explaining everything from scratch every visit.

Why choose a local team?

See how we compare to the big brands.

The big names

What you often get with the big names.

Rigid schedules that don't suit your kitchen hours

Different contractor every time who doesn't know your setup

Chase them for weeks to get waste transfer notes

Premium charges for anything outside standard hours

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OneFlow

What you get when you call us.

Flexible scheduling around your trading hours

Same local engineer who knows your kitchen

Waste documentation provided on the day, every time

No premium for early morning or evening visits

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Drainer of the
year 2025

The Drainage Awards

What our customers say

Real reviews from real customers.

“Called at 6am with sewage coming up through the shower. Engineer arrived before 8, fixed it within the hour. Can't thank them enough.”

— James T, Southampton

“Third company I'd tried that week. The other two never showed. OneFlow answered, turned up same day, and actually fixed it. Should have called them first.”

— Michelle R, Brighton

“No messing about. Showed me the camera footage, explained what was wrong, gave me a price, and got on with it. Exactly how it should be.”

— David H, Portsmouth

“Blocked drain on Christmas Eve. Thought we'd be stuck for days. They came out that evening and sorted it. Absolute lifesavers.”
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— Sarah K, Guildford

“We've used them for three rental properties now. Always answer the phone, always turn up, always fair on price. Hard to find.”
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— Mark L, Bournemouth

“Engineer was honest and said we didn't need half the work another company had quoted for. Saved us hundreds. We'll use them every time now.”

— Karen W, Winchester

“Toilet blocked on the morning of our daughter's birthday party. They had someone here within the hour and sorted it before the guests arrived.”

— Rachel M, Crawley

“Other companies quoted over the phone then doubled it on arrival. OneFlow quoted £180, charged £180.”
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— Tom S, Bournemouth

“Drainage issue had been misdiagnosed twice by other firms. OneFlow found the real problem in ten minutes with their camera. Fixed the same day.”

— Angela D, Eastbourne

“Rang at 11pm expecting to leave a voicemail. Actual person answered. Engineer here by midnight. Didn't think companies like this still existed.”

— Chris B, Woking

FAQs

Still have questions?

Get in touch with our friendly support team.

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★★★★★ based on 180+ Google reviews