Grease Trap Rules Solihull Restaurants | Stay Legal

If you run a café, takeaway, or restaurant in Solihull town centre, there's a decent chance your grease management setup isn't quite where it needs to be. Not because you're cutting corners. More often it's because nobody sat you down at the start and explained exactly what Severn Trent requires, what a trade effluent consent actually means, and what happens when an inspector comes knocking.

This post covers all of that. No scare tactics, no vague warnings. Just a clear explanation of the rules, what they mean in practice, and what you should do if you're not sure where you stand.

The Common Belief: A Grease Trap Is Just Good Practice

Most food business owners I speak to think of a grease trap in the same way they think of a fire extinguisher. Nice to have, obviously sensible, possibly required by their landlord. They fit one when they fit out the kitchen, they maybe get it cleaned once in a while, and they don't think much more about it.

That's understandable. The language around grease management is confusing, the rules aren't plastered on anyone's wall, and nobody from the council or Severn Trent showed up at opening and handed you a checklist.

But here's the thing. The grease trap sitting under your three-compartment sink isn't the whole story. For many commercial food premises in Solihull, there's a legal framework behind it that most owners have never been told about, and not knowing doesn't protect you if you end up in breach.

What Trade Effluent Consent Actually Means

In the UK, domestic sewers are designed to handle household wastewater. When a business discharges anything beyond what a household would produce, that legally becomes trade effluent. And trade effluent requires Severn Trent's written consent before it enters the public sewer.

Severn Trent is the sewerage undertaker for Solihull and the broader West Midlands, covering everything from the town centre out to the B postcodes running from B37 through to B94. So whether your kitchen is in the Mell Square area, out in Shirley, or you're running a small café in Knowle or Dickens Heath, the same regime applies.

Fats, oils, and grease, known collectively as FOG, are the main concern for food businesses. When you fry, roast, grill, or wash up after any of those, FOG goes into your drainage. Left unmanaged, it cools, solidifies, and coats the inside of the sewer. Over time you get a fatberg. Severn Trent clears hundreds of tonnes of that material from West Midlands sewers every year, and they've been getting progressively less patient about who's causing it.

A trade effluent consent sets out exactly what you're allowed to discharge, in what volumes, and under what conditions. For a food business, that almost always includes a requirement for grease interception before anything reaches the sewer.

Does Every Food Business Need One?

Not automatically. Severn Trent uses a threshold-based approach.

If your business produces trade effluent but in very small quantities and of a type that's similar in nature to domestic sewage, you may fall below the threshold where a full consent is needed. Some very small takeaways or low-throughput café kitchens sit in this zone.

But if you're:

• Cooking with oil or fat on a commercial scale
• Running a dishwasher rated for commercial throughput
• Producing wastewater from a commercial pot wash
• Operating a fish and chip shop, a curry house, a pizza kitchen, a burger bar, or any high-fat, high-volume operation

then the probability is high that you need consent, or at the very minimum you need to have had a conversation with Severn Trent and had them confirm in writing that you don't.

That last point matters. 'I didn't think I needed one' is not a defence. 'Severn Trent confirmed in writing that my discharge fell below the threshold' is.

What Severn Trent's Consent Regime Looks Like in Practice

Applying for trade effluent consent is a formal process. You submit an application to Severn Trent's Trade Effluent team, describing the nature of your discharge, the daily volume, the times of discharge, and what treatment or interception you have in place.

Severn Trent will assess it and issue a consent notice, which is a legal document setting out the conditions you must meet. Those conditions typically include:

• A grease trap or grease interceptor of a specified size (measured in litres of retained volume)
• A minimum cleaning frequency for that unit
• A requirement to keep records of cleaning, usually a service log signed by whoever does the work
• Fat, oil, and grease concentrations in the discharge that must stay below a set level (often 100mg/litre for FOG content)
• Sometimes, a requirement for a grease trap of a particular type, passive gravity interceptors for lower-volume sites, hydromechanical units for higher throughput

The consent is attached to the premises, not to you personally. If you buy or take on a lease of a food business, you're inheriting any existing consent and its conditions. Worth checking before you sign anything.

The Size Question: Why So Many Grease Traps Are Too Small

One of the most common problems I find when I'm called out to a commercial kitchen with a drainage complaint is a grease trap that's simply undersized for the operation it's meant to serve.

Passive grease traps work by allowing the wastewater to slow down and cool. FOG floats to the top, solids settle to the bottom, and cleaner water passes through the outlet in the middle. The trap needs to be big enough to give the water sufficient retention time, usually measured in minutes, to allow that separation to happen properly.

A 50-litre unit might be acceptable for a small sandwich bar doing light washing-up. It's hopelessly inadequate for a restaurant turning over 60 covers at lunch and 80 in the evening. The numbers on the side of the trap don't lie, but the salesperson who sold it to the previous tenant might not have done the calculation properly.

Severn Trent's guidance uses a formula based on the number of meals served per day, the type of cooking, and the volume of wastewater generated. If you haven't sized your trap against that formula, there's a reasonable chance it's not right.

What Triggers an Inspection

Severn Trent's Trade Effluent team has the legal power to enter your premises and inspect your drainage setup. They don't need a complaint to trigger a visit, but in practice there are a few things that bring them to your door.

A blockage downstream from your property. If a drain jetting crew clears a sewer and finds a grease accumulation that's traceable back to your stretch of the network, they'll flag it. The connection between your outfall and that blockage doesn't need to be proven beyond doubt for them to come and ask questions.

A complaint from a neighbouring business or resident. FOG in a shared drainage run can back up into someone else's property. That someone will call Severn Trent. Severn Trent will work back through the connected premises.

A routine audit. Severn Trent does carry out programme-led audits of trade effluent consent holders, particularly in areas with known sewer capacity problems. The town centre and denser commercial streets in Solihull fall into this category.

Your consent renewal. Consents are typically granted for three years. Renewal is an opportunity for Severn Trent to revisit your conditions and, if necessary, tighten them.

When an inspector comes, they'll want to see the trap itself, they'll assess its condition and size, they'll ask for your cleaning records, and they may take a sample from your outlet.

The Cost of Getting It Wrong

Let me be straightforward here, because this is where the seriousness of the regime is often undersold.

Discharging trade effluent without consent, or in breach of consent conditions, is an offence under the Water Industry Act 1991. Severn Trent can issue a formal notice requiring you to stop. If you don't comply, they can apply for an injunction. Beyond that, prosecution is possible, and convictions have resulted in fines running to tens of thousands of pounds for commercial operators.

But the financial hit that arrives soonest is usually more immediate than a fine. Severn Trent can levy charges for the cost of clearing any blockage or sewer remediation they attribute to your discharge. Those bills can be substantial, and they don't need a conviction to issue them.

Then there's the operational side. A cease notice, which is Severn Trent's power to require you to stop discharging, can effectively close a kitchen. No drainage means no cooking, and no cooking means no business.

None of this is designed to alarm you. It's designed to give you an accurate picture of what the regime actually is, so you can take sensible steps rather than finding out the hard way.

What a Properly Maintained Grease Trap Programme Looks Like

If you get this right, it doesn't have to be complicated. Here's what good looks like for a typical Solihull town centre food business:

A correctly sized unit, specified against Severn Trent's retention time formula for your volume and type of cooking.

A regular cleaning schedule, the frequency depends on the volume you're putting through, but most medium-sized operations need cleaning every four to eight weeks. Some high-throughput kitchens need it monthly or more often. If your trap smells, it's overdue.

A service log, every clean recorded with a date, the name of whoever did it, and the condition of the trap. Sewage waste removed from the trap is classified as controlled waste, so if you're using a contractor, they should provide you with a waste transfer note. Keep those.

Staff training, the basics. Don't pour cooking oil down the sink. Scrape plates before washing. Use mesh strainers on all outlets. These habits reduce the load on the trap enormously and extend the intervals between cleans.

A written record of your consent, filed somewhere you can find it if Severn Trent asks, along with any correspondence about it.

If You're Not Sure Where You Stand

Start with two things.

First, call Severn Trent's Trade Effluent team and ask whether your premises have a consent on record. The number to call is their business line, not the domestic number, and you'll want to have your business address and premises details to hand. If a consent exists, ask for a copy. If it doesn't, ask whether you need one based on your type of operation.

Second, get your grease trap looked at by someone who understands the commercial regime, not just someone who can empty it. The cleaning frequency, the size relative to your volume, and whether the unit itself is functioning correctly are all things worth having an independent set of eyes on.

If you're a landlord with food business tenants in Solihull town centre or the surrounding areas, Shirley, Olton, Monkspath, Marston Green, the same applies. The consent obligation and any breach of it may well involve you, particularly if the drainage infrastructure is under the landlord's maintenance responsibility. Worth knowing.

A Note on New Fit-Outs and Change of Use

If you're taking on a new unit that hasn't previously been used as a food business, or if you're changing from a low-heat operation to something with a full commercial kitchen, you need a new trade effluent consent before you start discharging. Not after. Before.

Building control and planning may require evidence of your drainage arrangements before they'll sign off anyway. Having your grease management specified and consented early makes that process easier and means you're not scrambling to retrofit something after you've already fitted out the kitchen.

Commercial kitchen drainage design is worth getting right from the start. Retrofitting a correctly sized grease interceptor into a finished kitchen is significantly more disruptive and more expensive than designing it in.

What Drainsco Can Do

Drainsco covers Solihull and the B postcodes with engineers on call around the clock. For commercial food businesses, we do grease trap installation and specification, regular maintenance contracts, high-pressure water jetting for commercial kitchen lines, CCTV drain surveys to show you exactly what's inside your drainage run, and gully and manhole clearance. We can also survey your setup and give you a written report that documents the condition and size of your grease interception, which is useful if you're preparing for a Severn Trent audit or putting a maintenance record together.

There's no call-out fee. Any remedial work, drain repairs, relining, pipe replacement, comes with a 20-year guarantee. You'll have a price before we start.

If you're not sure whether your current setup is compliant, a call to us is a sensible first step. We can tell you what we find and what, if anything, needs to change. No obligation beyond that.